U.S. patent application number 13/076139 was filed with the patent office on 2011-11-03 for remotely powered remotely adjustable gastric band system.
This patent application is currently assigned to ALLERGAN, INC.. Invention is credited to Tiago Bertolote, Joel Bonny, Pierre Fridez, Alain Jordan, Jean-Charles Montavon, Laurent Mosimann, Razack Osseni, Xavier Raemy, Xuan Mai Tu.
Application Number | 20110270025 13/076139 |
Document ID | / |
Family ID | 44351403 |
Filed Date | 2011-11-03 |
United States Patent
Application |
20110270025 |
Kind Code |
A1 |
Fridez; Pierre ; et
al. |
November 3, 2011 |
REMOTELY POWERED REMOTELY ADJUSTABLE GASTRIC BAND SYSTEM
Abstract
A remotely adjustable remotely power gastric band system may
include a control device, an implant electronic device, and an
implantable gastric band. The control device may telemetrically
power and communicate with the implant electronic device, which may
be used for adjusting the diameter of the implantable gastric band.
The implant electronic device may store the gastric band adjustment
history records of a patient and regulate the power received from
the control device. To improve transmission efficiency, the implant
electronic device may adopt a double modulation scheme for
communicating with the control device. Furthermore, the implant
electronic device may detect and resolve motor blockage issues
related to the implantable gastric band.
Inventors: |
Fridez; Pierre;
(Froideville, CH) ; Jordan; Alain; (Denges,
CH) ; Montavon; Jean-Charles; (Lausanne, CH) ;
Bertolote; Tiago; (Geneva, CH) ; Mosimann;
Laurent; (Commugny, CH) ; Raemy; Xavier;
(Belmont-sur-Lausanne, CH) ; Osseni; Razack;
(Lausanne, CH) ; Tu; Xuan Mai; (Ecublens, CH)
; Bonny; Joel; (Morges, CH) |
Assignee: |
ALLERGAN, INC.
Irvine
CA
|
Family ID: |
44351403 |
Appl. No.: |
13/076139 |
Filed: |
March 30, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61343571 |
Apr 30, 2010 |
|
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Current U.S.
Class: |
600/37 |
Current CPC
Class: |
H04B 5/0031 20130101;
H02J 7/00714 20200101; H02J 7/0071 20200101; H02J 50/10 20160201;
H02J 7/0042 20130101; H02J 5/005 20130101; H04B 5/0037 20130101;
H02J 7/007182 20200101; H02J 7/025 20130101; A61F 5/0059
20130101 |
Class at
Publication: |
600/37 |
International
Class: |
A61F 2/00 20060101
A61F002/00 |
Claims
1. A power system for use in conjunction with a gastric band
coupled with an implantable antenna for receiving a telemetric
signal from a remote control device, the power system comprising: a
rectifying device coupled to the implantable antenna, and
configured to rectify the received telemetric signal to form a DC
input voltage at a DC input node; a power sensing device configured
to receive the DC input voltage and generate a regulation signal
when the DC input voltage exceeds a predetermined threshold; a
regulation device coupled to the power sensing device, and
configured to generate a regulation voltage based on the regulation
signal; and a switching device coupled to the regulation device,
and configured to generate a feedback signal having a frequency
based on the regulation voltage.
2. The power system of claim 1, wherein the switching device
includes: a frequency modulation device coupled to the regulation
device, and configured to generate a frequency modulation signal
with a modulated frequency representing the regulation voltage,
wherein the feedback signal includes the frequency modulation
signal.
3. The power system of claim 2, wherein the switching device
includes: a switch coupled to the frequency modulation device, and
configured to generate, at the implement antenna, a modulated
amplitude for the feedback signal based on the modulated frequency
of the frequency modulation signal.
4. The power system of claim 3, wherein: the switching device
includes a pull down device coupled to the switch, and the switch
periodically connects the DC input voltage node to the pull down
device based on the modulated frequency of the frequency modulation
signal.
5. The power system of claim 1, wherein: the regulation voltage is
substantially the same as a local voltage before the regulation
signal is generated, a margin between the local voltage and the
regulation voltage is controlled by a voltage level of the
regulation signal, and the frequency of the feedback signal is
based on a margin between the regulation voltage and a local
voltage.
6. The power system of claim 1, wherein the regulation device
includes: a voltage regulator configured to receive the DC input
voltage and generate a local voltage less than the DC input voltage
and the predefined threshold, and a transistor coupled with the
voltage regulator, and configured to create a potential difference
between the local voltage and the regulation voltage, the potential
difference based on an amplified margin between the DC input
voltage and the predefined threshold.
7. The power system of claim 6, wherein the frequency of the
feedback signal is based on the potential difference between the
local voltage and the regulation voltage.
8. The power system of claim 1, wherein the regulation device
includes: a transistor configured to draw a regulation current
based on a voltage level of the regulation signal, a first resistor
configured to conduct the regulation current from a first node to a
second node, thereby building a potential difference between the
first node and the second node, and a second resistor configured to
conduct the regulation current from the second node to the
transistor, thereby building the regulation voltage at the second
node, and wherein the frequency of the feedback signal is based on
the potential difference between the first node and the second
node.
9. The power system of claim 1, wherein the power sensing device
includes: a Zener diode having a breakdown voltage substantially
equal to the predetermined threshold, and configured to draw a
breakdown current when the DC input voltage exceeds the breakdown
voltage, and a pull down resistor coupled to the Zener diode, and
configured to generate the regulation signal based on the breakdown
current.
10. A communication system for use in conjunction with a gastric
band coupled with an implantable antenna for receiving a telemetric
signal from a remote control device, the communication system
comprising: a regulation device configured to generate a regulation
voltage at a first node, the regulation voltage based on a margin
between a DC input voltage and a predetermined threshold; a data
path arranged in parallel with the regulation device, and
configured to adjust the regulation voltage to a set voltage at a
second node, the set voltage based partially on an output data
sequence; and a frequency modulation device coupled to the second
node, and configured to generate a frequency modulation signal
having a modulated frequency corresponding to the set voltage.
11. The communication system of claim 10, further comprising: a
switch coupled to the frequency modulation device, and configured
to generate, at the implement antenna, a modulated amplitude based
on the modulated frequency of the frequency modulation signal.
12. The communication system of claim 10, further comprising: a
third node coupled by the regulation device and the data path; and
a voltage regulator configured to generate a local voltage at the
third node, the local voltage less than the DC input voltage and
the predetermined threshold.
13. The communication system of claim 12, wherein: the regulation
device includes a first resistor configured to build a potential
difference between the third node and the first node based on the
margin between a DC input voltage and a predetermined threshold,
and the data path includes: a second resistor coupled to the second
node, and a data switch configured to selectively connect the
second resistor to the third node based on the output data
sequence.
14. The communication system of claim 12, wherein the modulated
frequency of the frequency modulated signal is based on a potential
difference between the local voltage and the set voltage.
15. A remotely powered and remotely adjustable gastric band system,
comprising: a remote control device configured to transmit a
telemetric signal having an amplitude and a carrier frequency; an
implantable power device telemetrically coupled to the remote
control device, and configured to extract power from the telemetric
signal and generate a feedback signal having a message frequency
based on the extracted power; and a gastric band for forming a
ventral ring surface around a stomach of a patient, the gastric
band coupled to the implantable power device, and configured to
receive the extracted power from the implantable power device and
adjust the ventral ring surface in response to the telemetric
signal.
16. The gastric band system of claim 15, wherein the implantable
power device includes: an implantable antenna for receiving the
telemetric signal from the remote control device, a rectifying
device coupled to the implantable antenna, and configured to
rectify the received telemetric signal to form the DC input voltage
at a DC input node, a power sensing device configured to receive a
DC input voltage and generate a regulation signal when the DC input
voltage exceeds a predetermined threshold, a regulation device
coupled to the power sensing device, and configured to generate a
regulation voltage based on the regulation signal, and a frequency
modulation device coupled to the regulation device, and configured
to generate a frequency modulation signal with a modulated
frequency representing the regulation voltage, wherein the message
frequency of the feedback signal tracks the modulated frequency of
the frequency modulation signal.
17. The gastric band system of claim 16, wherein the implantable
power device includes: a switch coupled to the frequency modulation
device, and configured to perform an amplitude modulation at the
implement antenna, the amplitude modulation adjust the amplitude of
the telemetric signal based on the frequency modulation signal.
18. The gastric band system of claim 15, wherein the remote control
device includes: an external antenna configured to transmit the
telemetric signal and receive the feedback signal, a sensing device
coupled to the external antenna, and configured to sense the
feedback signal, a demodulation device coupled to the sensing
device, and configured to extract the message frequency from the
sensed feedback signal and generate a voltage control signal based
on the message frequency, and a modulation device coupled to the
demodulation device and the external antenna, and configured to
adjust the amplitude of the telemetric signal based on the voltage
control signal and transmit the adjusted telemetric signal to the
external antenna.
19. The gastric band system of claim 15, wherein the sensing device
includes a directional coupler configured to separate the feedback
signal from the telemetric signal.
20. A method for detecting motor blockage of a motor for use in
conjunction with an implantable gastric band, the motor including a
motor coil for conducting a motor coil current and a plurality of
gears for adjusting an inner ring surface of the implantable
gastric band in response to the motor coil current, the method
comprising the steps of: applying a voltage pulse across the motor
coil; measuring a plurality of transient motor coil currents;
measuring a maximum motor coil current; and detecting the motor
blockage based on the plurality of transient motor coil currents
and the maximum motor coil current.
21. The method of claim 20, wherein the detecting includes the
steps of: calculating a sum of the plurality of transient motor
coil currents, comparing the sum of the plurality of transient
motor coil current with the maximum motor coil current, determining
an occurrence of motor blockage if the sum of the plurality of
transient motor coil current is greater than the maximum motor coil
current, and determining an absence of motor blockage if the sum of
the plurality of transient motor coil current is less than the
maximum motor coil current.
22. The method of claim 20, further comprising the step of:
increasing an output torque of the motor if the motor blockage is
detected.
23. The method of claim 20, further comprising the step of:
reducing a pulse width of the voltage pulse if the motor blockage
is detected.
24. The method of claim 20, further comprising the step of:
increasing a speed of the motor if the motor blockage is not
detected.
25. The method of claim 20, further comprising the step of:
increasing a pulse duration of the voltage pulse if the motor
blockage is not detected.
26. The method of claim 20, wherein the: the plurality transient
motor coil currents are measured during a middle period after an
initial period, and the maximum motor coil current is measured
during an ending period after the middle period.
27. The method of claim 26, wherein the voltage pulse includes a
first constant voltage pulse applied during the initial period, a
second constant voltage pulse applied during the initial period and
after the first constant voltage pulse, a third constant voltage
pulse applied during the middle period, and a fourth constant
voltage pulse applied during the ending period.
28. A tangible computer medium for storing instructions, upon being
executed by a processor, that cause the processor to perform a
method comprising the steps of: receiving measurements of a
plurality of transient motor coil currents conducted by a motor
coil of a motor for use in conjunction with an implantable gastric
band; receiving a measurement of a maximum motor coil current
conducted by the motor coil; and detecting a blockage of the motor
based on the measurements of the plurality of transient motor coil
currents and the measurement of the maximum motor coil current.
29. The tangible computer medium of claim 28, wherein the detecting
includes the steps of: calculating a sum of the measurements of the
plurality of transient motor coil currents, comparing the sum of
the measurements of the plurality of transient motor coil current
with the measurement of the maximum motor coil current, determining
an occurrence of motor blockage if the sum of the plurality of
transient motor coil current is greater than the maximum motor coil
current, and determining an absence of motor blockage if the sum of
the plurality of transient motor coil current is less than the
maximum motor coil current.
30. The tangible computer medium of claim 28, further comprising
instructions for executing the step of: generating a signal for
increasing an output torque of the motor if the motor blockage is
detected.
31. The tangible computer medium of claim 28, further comprising
instructions for executing the step of: generating a signal for
reducing a pulse width of the voltage pulse if the motor blockage
is detected.
32. The tangible computer medium of claim 28, further comprising
instructions for executing the step of: generating a signal for
increasing a speed of the motor if the motor blockage is not
detected.
33. The tangible computer medium of claim 28, further comprising
instructions for executing the step of: generating a signal for
increasing a pulse duration of the voltage pulse if the motor
blockage is not detected.
34. The tangible computer medium of claim 28, further comprising
instructions for executing the step of: generating a signal for
applying a voltage pulse across the motor coil during an initial
period.
35. The tangible computer medium of claim 34, wherein: the
measurements of the plurality transient motor coil currents are
taken during a middle period after the initial period, and the
measurement of the maximum motor coil current is taken during an
ending period after the middle period.
36. The tangible computer medium of claim 34, wherein the voltage
pulse includes a first constant voltage pulse applied during the
initial period, a second constant voltage pulse applied during the
initial period and after the first constant voltage pulse, a third
constant voltage pulse applied during the middle period, and a
fourth constant voltage pulse applied during the ending period.
37. A motorized gastric band system, comprising: an implantable
gastric band for forming a loop having a ventral surface for
contacting a stomach of a patient; a motor coupled to the
implantable gastric band, and including: a motor coil for
conducting a motor coil current, and a gear responsive to the motor
coil current, and for adjusting the ventral surface of the
implantable gastric band; and a processor coupled to the motor, and
configured to: receive measurements of a plurality of transient
motor coil currents conducted by the motor coil, receive a
measurement of a maximum motor coil current conducted by the motor
coil, and detect a blockage of the motor based on the measurements
of the plurality of transient motor coil currents and the
measurement of the maximum motor coil current.
38. The motorized gastric band of claim 37, further comprising: a
resistor connecting in series with the motor coil, and configured
to conduct the plurality of transient motor coil currents and the
maximum motor coil current.
39. The motorized gastric band of claim 38, wherein: the resistor
has a first resistance, the motor coil has a second resistance, and
the second resistance is about 167 times of the first
resistance.
40. The motorized gastric band of claim 38, further comprising: an
analog amplifier arranged in parallel with the resistor, configured
to measure and amplify the plurality of transient motor coil
currents and the maximum motor coil current; and an
analog-to-digital convertor (ADC) coupled to the analog amplifier,
and configure to: digitize the amplified measurements of a
plurality of transient motor coil currents and the amplified
measurement of the maximum motor coil current, and deliver the
digitized measurements of a plurality of transient motor coil
currents and the digitized measurement of the maximum motor coil
current to the processor.
41. The motorized gastric band of claim 37, wherein the processor
is configured to: calculate a sum of the measurements of the
plurality of transient motor coil currents, compare the sum of the
measurements of the plurality of transient motor coil current with
the measurement of the maximum motor coil current, determine an
occurrence of motor blockage if the sum of the plurality of
transient motor coil current is greater than the maximum motor coil
current, and determine an absence of motor blockage if the sum of
the plurality of transient motor coil current is less than the
maximum motor coil current.
42. The motorized gastric band of claim 37, wherein the processor
is configured to generate a signal for increasing an output torque
of the motor if the motor blockage is detected.
43. The motorized gastric band of claim 37, wherein the processor
is configured to generate a signal for reducing a pulse width of
the voltage pulse if the motor blockage is detected.
44. The motorized gastric band of claim 37, wherein the processor
is configured to generate a signal for increasing a speed of the
motor if the motor blockage is not detected.
45. The motorized gastric band of claim 37, wherein the processor
is configured to generate a signal for increasing a pulse duration
of the voltage pulse if the motor blockage is not detected.
46. The motorized gastric band of claim 37, wherein the processor
is configured to generate a signal for applying a voltage pulse
across the motor coil during an initial period.
47. The motorized gastric band of claim 46, wherein: the
measurements of the plurality transient motor coil currents are
taken during a middle period after the initial period, and the
measurement of the maximum motor coil current is taken during an
ending period after the middle period.
48. The motorized gastric band of claim 46, wherein the voltage
pulse includes: a first constant voltage pulse applied during the
initial period, a second constant voltage pulse applied during the
initial period and after the first constant voltage pulse, a third
constant voltage pulse applied during the middle period, and a
fourth constant voltage pulse applied during the ending period.
49. A retractable antenna device for a remotely adjustable and
remotely powered an implantable gastric band, comprising: a housing
having a top wall and a bottom wall; a winding drum disposed within
the housing and along the axle, the winding drum having a neck and
a base, the winding drum is configured to rotate about an axis
between a first position and a second position; an antenna disposed
between the base of the winding drum and the bottom wall of the
housing; a cable configured to coil around the neck of the winding
drum when the winding drum is at the first position, and configured
to uncoil and substantially extend outside of the housing when the
winding drum is at the second position; and a locking device
configured to lock the winding drum when the winding drum rotates
from the first position to reach the second position, so that the
winding drum remains stationary at the second position.
50. The retractable antenna device of claim 49, further comprising:
an axle engaging the top wall and the bottom wall along the axis
about which the winding drum rotates.
51. The retractable antenna device of claim 49, wherein the locking
device is configured to produce a sound when the winding drum is
locked.
52. The retractable antenna device of claim 49, wherein a
substantial portion of the cable is disposed within the housing
when the winding drum is at a first position.
53. A remote control device for use in conjunction with a remotely
adjustable and remotely powered implantable gastric band,
comprising: a handle; a display screen having a proximal side and a
distal side, the proximal side positioned between the handle and
the distal side; a sensing device configured to determine an
orientation of the remote control device by sensing the relative
position of the distal side and the proximal side of the display
screen; and a processing device coupled to the sensing device,
configured to transmit a display signal to the display screen for
displaying an image on the display screen with a first image
orientation or a second image orientation depending on the
orientation of the remote control device, and configured to adjust
the implantable gastric band.
54. The remote control device of claim 53, further comprising: a
left button; and a right button, wherein the processor configured
to activate the left button and deactivate the right button when
the image is displayed with the first image orientation, and the
processor configured to activate the right button and deactivate
the left button when the image is displayed with the second image
orientation.
55. A system for rapidly charging a remote control device for
remotely adjusting and powering an implantable gastric band via a
telemetric coupling, comprising: a battery for providing power to
the remote control device, and having a battery voltage; and a
charging station for charging the battery, the charging station
configured to monitor the battery voltage of the battery, deliver a
constant charging current to the battery until the battery voltage
reaches a predefined threshold, and deliver a constant charging
voltage to the remote control device thereafter to maintain the
battery voltage.
56. A system for remotely adjusting and powering an implantable
gastric band configured to be installed around a stomach of a
patient, comprising: an implantable memory configured to be
disposed inside the patient and to store a patient record relatable
to the patient and an adjustment record relatable to an adjustment
history of the implantable gastric band; and a processor coupled to
the memory, and configured to: retrieve the adjustment history upon
receiving a telemetric data retrieval signal from a remote control
device, generate a signal for adjusting the implantable gastric
band upon receiving a telemetric band adjustment signal from the
remote control device, and update the adjustment record based on
the telemetric band adjustment signal.
57. An implantable gastric band, comprising: a tubular member
having a first end and a second end, the second end defining an
opening, the first end having a flange configured to engage the
second end of the tubular member, thereby forming a tubular ring
having an adjustable ventral ring surface and a substantially rigid
dorsal ring surface; a skeleton disposed between the adjustable
ventral ring surface and the substantially rigid dorsal ring
surface of the tubular ring, the skeleton having a distal end
pushing against the first end of the tubular member and a proximal
end pushing against the second end of the tubular member, the
skeleton configured to support the substantially rigid dorsal ring
surface of the tubular ring; a flexible screw slid between the
skeleton and the adjustable ventral ring surface, the flexible
screw having a hook anchoring the distal end of the skeleton and a
crimped end extending beyond the opening of the tubular member, the
flexible screw having an outer portion disposed outside of the
tubular ring and an inner portion disposed inside of the tubular
ring, the inner portion of the flexible screw defining a
circumference of the adjustable ventral ring surface; a motor
anchoring the proximal end of the skeleton and engaging the
flexible screw, and configured to increase or decrease the inner
portion of the flexible screw, thereby adjusting the circumference
of the adjustable ventral ring surface; a processor for receiving
an telemetric signal and for controlling the motor; and a cable
having a processor end coupled to the processor and a motor end
coupled to the motor.
58. The implantable gastric band of claim 57, further comprising: a
sheath for encapsulating the processor end of the cable and
stabilizing the coupling between the cable and the processor.
59. The implantable gastric band of claim 57, wherein the motor
includes a protective sleeve configured to seal the motor and
stabilize the coupling between the cable and the motor.
60. The implantable gastric band of claim 57, wherein the flange
includes: an inner striated surface for engaging the second end of
the tubular member; and a tongue for clipping onto and securing the
second end of the tubular member.
61. The implantable gastric band of claim 57, wherein the second
end of the tubular element has a marking device visible when the
second end of the tubular element is engaged by the flange of the
first end.
62. The implantable gastric band of claim 57, wherein the tubular
element includes: a dorsal arch having a groove configured to align
the skeleton element; and a stretchable sleeve configured to
encapsulate a substantial portion of the dorsal arch.
63. The implantable gastric band of claim 57, further comprising a
manipulation handle having: a base end configured to be coupled
with the processor; a tapered end, the tapered end is substantially
narrower than the base end; a helicoidal body connecting the base
end and the tapered end, and having a first thickness adjacent to
the base end and a second thickness adjacent to the tapered end,
the first thickness is greater than the second thickness; and a
plurality of arrow markers disposed serially along the helicoidal
body and pointing towards the tapered end, the plurality of arrow
markers.
64. The implantable gastric band of claim 57, wherein the cable
includes: a plurality of motor wire pairs, each connecting the
processor to the motor and including a nominal motor wire and a
redundant motor wire; and a central ground wire surrounded by the
plurality of motor wire pairs.
65. The implantable gastric band of claim 57, further comprising a
plurality of cushion members positioned along the adjustable
ventral ring surface of the tubular ring, each of the plurality of
cushion members having: a front portion having a convex surface
engraved with a plurality of grooves selected from a group
consisting of straight lines, curvy lines, and combinations
thereof, and a back portion facing the adjustable ventral ring
surface, the front portion.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to and the benefit of U.S.
Provisional Application No. 61/343,571, filed on Apr. 30, 2010,
which is assigned to the assignee hereof and hereby expressly
incorporated by reference herein.
FIELD
[0002] The present invention generally relates to medical systems
and apparatus and uses thereof for treating obesity and/or
obesity-related diseases, and more specifically, related to gastric
band systems that are remotely adjustable and remotely powered by a
wireless control device.
BACKGROUND
[0003] Adjustable gastric banding apparatus have provided an
effective and substantially less invasive alternative to gastric
bypass surgery and other conventional surgical weight loss
procedures. Despite the positive outcomes of invasive weight loss
procedures, such as gastric bypass surgery, it has been recognized
that sustained weight loss can be achieved through a
laparoscopically-placed gastric band, for example, the
LAP-BAND.RTM. (Allergan, Inc., Irvine, Calif.) gastric band or the
LAP-BAND AP.RTM. (Allergan, Inc., Irvine, Calif.) gastric band.
Generally, gastric bands are placed about the cardia, or upper
portion, of a patient's stomach forming a stoma that restricts the
passage of food into a lower portion of the stomach. When the stoma
is of an appropriate size that is restricted by a gastric band,
food held in the upper portion of the stomach provides a feeling of
satiety or fullness that discourages overeating. Unlike gastric
bypass procedures, the gastric band apparatus are reversible and
require no permanent modification to the gastrointestinal
tract.
[0004] Over time, a stoma created by a gastric band may need
adjustment in order to maintain an appropriate size, which is
neither too restrictive nor too passive. Some non-invasive
procedures for adjustment of gastric bands without the use of a
hypodermic needle have been proposed. For example, a remotely
adjustable gastric band is a medical device which allows a
healthcare worker to adjust a gastric band without requiring
hypodermic needles to connect to an implanted, subcutaneous access
port. A handheld controller can be used to send radio frequency
waves for powering and communicating with the implanted device. The
implanted device can tighten or relax the gastric band as requested
by the healthcare worker via the handheld controller.
[0005] Birk, et al., U.S. Patent Pub. No. 2010-0010291, and Birk,
et al., U.S. Ser. No. 12/705,245, which are commonly-assigned and
co-pending with the present application, are incorporated herein in
their entirety by this specific reference. Both of these
applications disclose certain approaches to implantable systems
that may be relevant.
[0006] Some mechanically adjustable implantable devices have a
disadvantage of becoming inoperable if the adjustment mechanism
fails. Furthermore, because the motor and the driving mechanisms
are located near the restricting band itself, they are more subject
to strain and damage from the implantation process. Therefore, it
is desirable to develop a remotely adjustable gastric band where
the motor is separated from the restricting band to reduce the
strain from the implantation process such that the risk of damage
during implantation is decreased.
[0007] Thus, there continues to remain a need for more effective
implantable motor systems for use with adjustable gastric bands,
particularly such implantable motor systems with increased and more
efficient motoring capability.
SUMMARY
[0008] Generally described herein are remotely adjustable and
remotely powered gastric band systems, and methods of use thereof.
The apparatus, systems and methods described herein aid in
facilitating obesity control and/or treating obesity related dieses
while being non-invasive once implanted.
[0009] In one embodiment, the present may provide a power system
for use in conjunction with a gastric band coupled with an
implantable antenna for receiving a telemetric signal from a remote
control device. The power system may include a rectifying device
coupled to the implantable antenna, and configured to rectify the
received telemetric signal to form a DC input voltage at a DC input
node, a power sensing device configured to receive the DC input
voltage and generate a regulation signal when the DC input voltage
exceeds a predetermined threshold, a regulation device coupled to
the power sensing device, and configured to generate a regulation
voltage based on the regulation signal, and a switching device
coupled to the regulation device, and configured to generate a
feedback signal having a frequency based on the regulation
voltage.
[0010] In another embodiment, the present invention may provide a
communication system for use in conjunction with a gastric band
coupled with an implantable antenna for receiving a telemetric
signal from a remote control device. The communication system may
include a regulation device configured to generate a regulation
voltage at a first node, the regulation voltage based on a margin
between a DC input voltage and a predetermined threshold, a data
path arranged in parallel with the regulation device, and
configured to adjust the regulation voltage to a set voltage at a
second node, the set voltage based partially on an output data
sequence, and a frequency modulation device coupled to the second
node, and configured to generate a frequency modulation signal
having a modulated frequency corresponding to the set voltage.
[0011] In another embodiment, the present invention may provide a
remotely powered and remotely adjustable gastric band system, which
may include a remote control device configured to transmit a
telemetric signal having an amplitude and a carrier frequency, an
implantable power device telemetrically coupled to the remote
control device, and configured to extract power from the telemetric
signal and generate a feedback signal having a message frequency
based on the extracted power, and a gastric band for forming a
ventral ring surface around a stomach of a patient, the gastric
band coupled to the implantable power device, and configured to
receive the extracted power from the implantable power device and
adjust the ventral ring surface in response to the telemetric
signal.
[0012] In another embodiment, the present invention may provide a
method for detecting motor blockage of a motor for use in
conjunction with an implantable gastric band. The motor may include
a motor coil for conducting a motor coil current and a plurality of
gears for adjusting an inner ring surface of the implantable
gastric band in response to the motor coil current. The method may
include the steps of applying a voltage pulse across the motor
coil, measuring a plurality of transient motor coil currents,
measuring a maximum motor coil current, and detecting the motor
blockage based on the plurality of transient motor coil currents
and the maximum motor coil current.
[0013] In another embodiment, the present invention may provide a
tangible computer medium for storing instructions, upon being
executed by a processor, that cause the processor to perform a
method, which may comprise the steps of receiving measurements of a
plurality of transient motor coil currents conducted by a motor
coil of a motor for use in conjunction with an implantable gastric
band, receiving a measurement of a maximum motor coil current
conducted by the motor coil, and detecting a blockage of the motor
based on the measurements of the plurality of transient motor coil
currents and the measurement of the maximum motor coil current.
[0014] In another embodiment, the present invention may provide a
motorized gastric band system, which may include an implantable
gastric band for forming a loop having a ventral surface for
contacting a stomach of a patient, a motor coupled to the
implantable gastric band, and including a motor coil for conducting
a motor coil current, and a gear responsive to the motor coil
current, and for adjusting the ventral surface of the implantable
gastric band, and a processor coupled to the motor, and configured
to receive measurements of a plurality of transient motor coil
currents conducted by the motor coil, receive a measurement of a
maximum motor coil current conducted by the motor coil, and detect
a blockage of the motor based on the measurements of the plurality
of transient motor coil currents and the measurement of the maximum
motor coil current.
[0015] In another embodiment, the present invention may include a
retractable antenna device for a remotely adjustable and remotely
powered an implantable gastric band. The retractable antenna device
may include a housing having a top wall and a bottom wall, a
winding drum disposed within the housing and along the axle, the
winding drum having a neck and a base, the winding drum is
configured to rotate about an axis between a first position and a
second position, an antenna disposed between the base of the
winding drum and the bottom wall of the housing, a cable configured
to coil around the neck of the winding drum when the winding drum
is at the first position, and configured to uncoil and
substantially extend outside of the housing when the winding drum
is at the second position, and a locking device configured to lock
the winding drum when the winding drum rotates from the first
position to reach the second position, so that the winding drum
remains stationary at the second position.
[0016] In another embodiment, the present invention may provide a
remote control device for use in conjunction with a remotely
adjustable and remotely powered implantable gastric band. The
remote control device may include a handle, a display screen having
a proximal side and a distal side, the proximal side positioned
between the handle and the distal side, a sensing device configured
to determine an orientation of the remote control device by sensing
the relative position of the distal side and the proximal side of
the display screen, and a processing device coupled to the sensing
device, configured to transmit a display signal to the display
screen for displaying an image on the display screen with a first
image orientation or a second image orientation depending on the
orientation of the remote control device, and configured to adjust
the implantable gastric band.
[0017] In another embodiment, the present invention may provide a
system for rapidly charging a remote control device for remotely
adjusting and powering an implantable gastric band via a telemetric
coupling. The system may include a battery for providing power to
the remote control device, and having a battery voltage, and a
charging station for charging the battery, the charging station
configured to monitor the battery voltage of the battery, deliver a
constant charging current to the battery until the battery voltage
reaches a predefined threshold, and deliver a constant charging
voltage to the remote control device thereafter to maintain the
battery voltage.
[0018] In another embodiment, the present invention may provide a
system for remotely adjusting and powering an implantable gastric
band configured to be installed around a stomach of a patient. The
system may include an implantable memory configured to be disposed
inside the patient and to store a patient record relatable to the
patient and an adjustment record relatable to an adjustment history
of the implantable gastric band, and a processor coupled to the
memory, and configured to retrieve the adjustment history upon
receiving a telemetric data retrieval signal from a remote control
device, generate a signal for adjusting the implantable gastric
band upon receiving a telemetric band adjustment signal from the
remote control device, and update the adjustment record based on
the telemetric band adjustment signal.
[0019] In yet another embodiment, the present invention may provide
an implantable gastric band, which may include a tubular member
having a first end and a second end, the second end defining an
opening, the first end having a flange configured to engage the
second end of the tubular member, thereby forming a tubular ring
having an adjustable ventral ring surface and a substantially rigid
dorsal ring surface, a skeleton disposed between the adjustable
ventral ring surface and the substantially rigid dorsal ring
surface of the tubular ring, the skeleton having a distal end
pushing against the first end of the tubular member and a proximal
end pushing against the second end of the tubular member, the
skeleton configured to support the substantially rigid dorsal ring
surface of the tubular ring, a flexible screw slid between the
skeleton and the adjustable ventral ring surface, the flexible
screw having a hook anchoring the distal end of the skeleton and a
crimped end extending beyond the opening of the tubular member, the
flexible screw having an outer portion disposed outside of the
tubular ring and an inner portion disposed inside of the tubular
ring, the inner portion of the flexible screw defining a
circumference of the adjustable ventral ring surface, a motor
anchoring the proximal end of the skeleton and engaging the
flexible screw, and configured to increase or decrease the inner
portion of the flexible screw, thereby adjusting the circumference
of the adjustable ventral ring surface, a processor for receiving
an telemetric signal and for controlling the motor, and a cable
having a processor end coupled to the processor and a motor end
coupled to the motor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The features, objects, and advantages of the invention will
become more apparent from the detailed description set forth below
when taken in conjunction with the drawings, wherein:
[0021] FIG. 1 shows a perspective view of a remotely adjustable
remotely powered (RARP) gastric band system according to an
embodiment of the present invention;
[0022] FIG. 2 shows a perspective view of various external
components of the RARP gastric band system according to an
embodiment of the present invention;
[0023] FIG. 3 shows a block diagram of the RARP gastric band system
according to an embodiment of the present invention;
[0024] FIG. 4 shows a system architecture block diagram of the RARP
gastric band system according to an embodiment of the present
invention;
[0025] FIGS. 5A-5B show the button configuration and display screen
orientation of a control device according to an embodiment of the
present invention;
[0026] FIG. 6 shows an exploded view of a control device according
to an embodiment of the present invention;
[0027] FIG. 7 shows the perspective bottom and top views of a Human
Interface Device (HID) Printed Circuit Board (PCB) being coupled to
a Radio Frequency (RF) Printed Circuit Board (PCB) according to an
embodiment of the present invention;
[0028] FIGS. 8A-8R show the sample screen shots of the control
device according to an embodiment of the present invention;
[0029] FIG. 9 shows a schematic view of the HID subsystem according
to an embodiment of the present invention;
[0030] FIG. 10 shows a perspective view of the HID PCB components
and connectors according to an embodiment of the present
invention;
[0031] FIG. 11 shows a schematic view of the RF subsystem according
to an embodiment of the present invention;
[0032] FIG. 12 shows a perspective view of the RF PCB components
and connectors according to an embodiment of the present
invention;
[0033] FIG. 13 shows a schematic view of a power regulation
subsystem of the RARP gastric band system according to an
embodiment of the present invention;
[0034] FIG. 14 shows a schematic view of a modulation device
according to an embodiment of the present invention;
[0035] FIG. 15 shows a diagram with an ideal voltage curve and an
ideal current curve of a Class E amplifier according to an
embodiment of the present invention;
[0036] FIG. 16 shows the adjustability of tail end of the voltage
curve in the Class E amplifier according to an embodiment of the
present invention;
[0037] FIG. 17 shows a schematic view of a rectifying device
according to an embodiment of the present invention;
[0038] FIG. 18 shows an implant power regulation subsystem
according to an embodiment of the present invention;
[0039] FIG. 19 shows various waveforms of various signals of the
implant power regulation subsystem according to an embodiment of
the present invention;
[0040] FIG. 20 shows various waveforms of a double modulation
(frequency modulated amplitude modulation) scheme according to an
embodiment of the present invention;
[0041] FIG. 21 shows a schematic view of a double modulation
subsystem according to an embodiment of the present invention;
[0042] FIG. 22 shows a frequency chart of the double modulation
scheme according to an embodiment of the present invention;
[0043] FIG. 23A shows a frequency spectrum of the frequency
modulation feedback signal according to an embodiment of the
present invention;
[0044] FIG. 23B shows a demodulation of the frequency modulated
amplitude modulation signal according to an embodiment of the
present invention;
[0045] FIG. 24 shows a schematic view of a demodulation device
according to an embodiment of the present invention;
[0046] FIG. 25 shows the relationship among various signals of the
demodulation device and a distance between the external antenna and
the implant antenna according to an embodiment of the present
invention;
[0047] FIG. 26 shows the communication protocol among the HID
subsystem, RF subsystem and the implant according to an embodiment
of the present invention;
[0048] FIG. 27 shows the state diagram of an HID subsystem
algorithm according to an embodiment of the present invention;
[0049] FIG. 28 shows the state diagram of an RF subsystem algorithm
according to an embodiment of the present invention;
[0050] FIG. 29A shows a command only communication protocol between
the HID and RF subsystems according to an embodiment of the present
invention;
[0051] FIG. 29B shows a command-data communication protocol between
the HID and RF subsystems according to an embodiment of the present
invention;
[0052] FIG. 30 shows an answer message communication protocol from
the RF subsystem according to an embodiment of the present
invention;
[0053] FIG. 31 shows a notification message communication protocol
from the RF subsystem according to an embodiment of the present
invention;
[0054] FIGS. 32A-32C show an exploded view, a front view and a back
view of a docking station according to an embodiment of the present
invention;
[0055] FIG. 33 shows a schematic view of the docking station
interacting with the RF Board according to an embodiment of the
present invention;
[0056] FIG. 34 shows a fast charge mode voltage-current chart
according to an embodiment of the present invention;
[0057] FIGS. 35A-35B show a perspective view and an exploded view
of an external antenna with a retractable cable according to an
embodiment of the present invention;
[0058] FIGS. 36A-36B show a perspective front view and a
perspective back view of the retractable external antenna being
stored at the back of the control device according to an embodiment
of the present invention;
[0059] FIGS. 37A-37B show a perspective view and an exploded view
of the implant according to an embodiment of the present
invention;
[0060] FIGS. 38A-38F show the perspective views of various implant
electronic device protection case components according to an
embodiment of the present invention;
[0061] FIGS. 39A-39B show a top view and a bottom view of an
implant electronic system board according to an embodiment of the
present invention;
[0062] FIGS. 40A-40C show various views of a manipulation handle
according to an embodiment of the present invention;
[0063] FIG. 41 shows a state diagram of implant electronic device
software algorithm according to an embodiment of the present
invention;
[0064] FIGS. 42A-42B show a transmission sequence and a data
structure of an identification message to the control device
according to an embodiment of the present invention;
[0065] FIGS. 43A-43B show the command only protocol and a data
structure of the command according to an embodiment of the present
invention;
[0066] FIGS. 44A-44B show the command-parameter protocol and a data
structure of the command-parameter according to an embodiment of
the present invention;
[0067] FIGS. 45A-45B show the data structures of an ACK message and
a NACK message according to an embodiment of the present
invention;
[0068] FIG. 46A shows a command-response protocol according to an
embodiment of the present invention;
[0069] FIG. 46B shows a data structure of a response message
according to an embodiment of the present invention;
[0070] FIG. 47A shows a time out protocol with control device
checksum according to an embodiment of the present invention;
[0071] FIG. 47B shows a time out protocol with implant checksum
according to an embodiment of the present invention;
[0072] FIG. 48 shows a data structure of implant adjustment history
record according to an embodiment of the present invention;
[0073] FIG. 49 shows a timing diagram of a computer interrupt upon
a detection of a control device command at the implant according to
an embodiment of the present invention;
[0074] FIG. 50 shows a timing diagram of the control device's
command and the implant's response according to an embodiment of
the present invention;
[0075] FIG. 51 shows a schematic view of a motor coil current
measurement system according to an embodiment of the present
invention;
[0076] FIG. 52 shows a graph for measuring an integral motor coil
current according to an embodiment of the present invention;
[0077] FIG. 53 shows a graph for measuring a maximum motor coil
current according to an embodiment of the present invention;
[0078] FIG. 54 shows a software algorithm for detecting motor
blockage according to an embodiment of the present invention;
[0079] FIGS. 55A-55B show a perspective top view and a perspective
bottom view of a motor according to an embodiment of the present
invention;
[0080] FIGS. 55C-55D show a perspective bottom view and a
perspective top view of a motor cap according to an embodiment of
the present invention;
[0081] FIGS. 55E-55F show a perspective bottom view and a
perspective top view of a motor traveling PCB protection cap
according to an embodiment of the present invention;
[0082] FIGS. 55G-55H show a perspective side view and a side view
of a motor sleeve according to an embodiment of the present
invention;
[0083] FIG. 55I shows an exploded view of a motor coil according to
an embodiment of the present invention;
[0084] FIGS. 55J-55K show various views of the motor cable
according to an embodiment of the present invention;
[0085] FIG. 56 shows a side view of a flexible screw according to
an embodiment of the present invention;
[0086] FIGS. 57A-57H show various views of the motor engaging the
flexible screw according to an embodiment of the present
invention;
[0087] FIGS. 58A-58C show various views of a bendable skeleton
embedded with a stabilizing tube according to an embodiment of the
present invention;
[0088] FIGS. 59A-59B show a perspective view and a cross-sectional
view of the stabilizing tube according to an embodiment of the
present invention;
[0089] FIGS. 60A-60D show various views of a dorsal element
according to an embodiment of the present invention;
[0090] FIGS. 61A-61C show various views of an anti-slip cushion
according to an embodiment of the present invention;
[0091] FIGS. 62A-62C show various views of a membrane shell
according to an embodiment of the present invention; and
[0092] FIGS. 63A-63C show various views of a cushioned membrane
shell according to an embodiment of the present invention.
DETAILED DESCRIPTION
[0093] In FIG. 1, a remotely adjustable and remotely powered (RARP)
gastric band system 100 is shown according to an embodiment of the
present invention. Generally, the RARP gastric band system 100 may
include an external subsystem and an implant (internal) subsystem.
The external subsystem may include a control device (a.k.a. control
unit) 110, an external antenna 120, and a retractable antenna cable
114, which may be used for coupling the external antenna 120 to the
control device 110.
[0094] From a high level standpoint, the control device 110 may
serve various functions. In one embodiment, for example, the
control device 110 may be used as an interface for a user, such as
a physician or a care taker. In another embodiment, for example,
the control device 110 may be used for transmitting telemetric
signal 122 to the implant 130 for inducing power therein. In yet
another embodiment, for example, the control device 110 may be used
for remotely controlling various functionalities of the implant
130, such as adjusting the size of a gastric band 180, retrieving
information from the implant memory device 150, and/or regulating
power inside the implant 130.
[0095] The implant subsystem (a.k.a. the implant) 130 may be
implanted inside a patient's body 101, and it may include an
implant electronic device 132, a gastric band 180, a motor 170, and
a motor cable 142. The gastric band 180 may be used for forming a
stoma around the patient's stomach 102, and the motor 170 may be
used for controlling the gastric band 180, which may in turn,
adjust the size of the stoma. Moreover, the implant electronic
device 132 may include an implant (internal) antenna 160, a
microprocessor (a.k.a. microcontroller) 140, and a memory device
150.
[0096] From a high level standpoint, the microprocessor 140 may
serve various functions. In one embodiment, for example, the
microprocessor 140 may coordinate the reception, rectification, and
regulation of power received via the implant antenna 160.
Generally, the implant antenna 160 may receive the signal
transmitted from the external antenna 120 when they are separated
by a distance of about 3 cm or less. In another embodiment, for
example, the microprocessor 140 may retrieve past gastric band
adjustment information from the memory device 150 or store current
gastric band adjustment information to the memory device 150. In
yet another embodiment, for example, the microprocessor 140 may
control the motor 170 for adjusting the gastric band 180, and for
detecting and preventing motor blockage.
[0097] In FIG. 2, a perspective view of various external subsystem
components of the RARP gastric band system 100 are shown according
to various embodiments of the present invention. In addition to the
control device 110 and the external antenna 120, the external
subsystem 200 may include a carrying case 201, a power adaptor 202,
a power cord 204, and a docking station 208.
[0098] The power adaptor 202 may connect a power source (not shown)
to the docking station 208, such that the docking station 208 may
receive electricity for charging the control device 110. The
external antenna 120 may be connected to the control device 110
(interchangeably "control unit") during gastric band adjustment.
The external antenna 120 may be stored at the back of the control
device 110 when it is not in use. In between gastric adjustments,
the control device 110 may be docked at the docking station 208 for
recharging. The connection between the control device 110 and the
docking station 208 may be established by contacting several spring
loaded connectors located on the docking station 208 with several
matching metallic surfaces located on the control device 110. The
spring loaded connectors and the matching metallic surfaces may
provide additional physical stability when the control device 206
is docked at the docking station 208.
[0099] FIG. 3 shows a block diagram of a RARP gastric band system
300 according to an embodiment of the present invention. Generally,
the RARP gastric band system 300 may include the control device
110, the docking station 208, the external antenna 120, and the
implant 130. Particularly, the control device 110 may include a
Human Interface Device (HID) board 310 and a Radio Frequency (RF)
board 320.
[0100] The HID board 310 may be used for implementing an HID
subsystem. The HID subsystem may receive input from a user and
generate output for the user during or in between gastric band
adjustments. As such, a physician and/or a care taker may use the
HID subsystem to adjust the size of the gastric band and to
retrieve information regarding the gastric band adjustment history
of a particular patient. The size of the gastric band can be
understood as diameter of a ventral (inner) ring surface of the
gastric band.
[0101] The RF board 320 may be used for implementing an RF
subsystem. The RF subsystem may execute various tasks as instructed
by the HID subsystem. Generally, the HID subsystem and the RF
subsystem may setup a master-slave configuration 324, in which the
HID subsystem may command the RF subsystem to perform a recharging
task, a power transmission task, a band adjustment task, and/or an
information retrieval task.
[0102] To perform the recharging task, the RF subsystem may
establish a power connection 326 with the docking station 208. The
power connection 326 may be used for transmitting power from the
docking station 208 to the RF board 320. Moreover, the power
connection 326 may conduct signals that may be used for monitoring
and controlling the recharge process.
[0103] To perform the power transmission task, the RF subsystem may
drive the external antenna 120 with an RF signal that induces power
in the implant 130. Generally, the RF signal may be amplitude
modulated and have a carrier frequency within the radio frequency
range. In one embodiment, for example, the carrier frequency may
range from about 30 kHz to about 300 GHz. In another embodiment,
for example, the carrier frequency may range from about 10 MHz to
about 50 MHz. In yet another embodiment, for example, the carrier
frequency may approximately be about 27 MHz.
[0104] To perform the band adjustment task, the RF subsystem may
momentarily transmit adjustment instruction via the external
antenna 120 to the implant 130. The transmission of the adjustment
instruction may include a series of handshake protocols, which may
ensure that the adjustment instruction is being received and
executed properly by the implant 130.
[0105] To perform the information retrieval task, the RF subsystem
may sense and demodulate a feedback signal from the implant 130.
Generally, the feedback signal may be a double modulation signal,
which may include a frequency modulation component and an amplitude
modulation component. In one embodiment, for example, the frequency
modulation component may be used for embedding gastric band
adjustment data and power regulation signal while the amplitude
modulation component may be used as a carrier. In another
embodiment, for example, the amplitude modulation component may be
used for embedding gastric band adjustment data and power
regulation signal while the amplitude modulation component may be
used as the carrier.
[0106] FIG. 4 shows a system architecture block diagram of a RARP
gastric band system 400 according to an embodiment of the present
invention. Generally, the RARP gastric band system 400 may include
an external system 410 and an implant (internal) system 470. The
external system 410 may include an HID subsystem 420, an RF
subsystem 430, an external antenna 440, a docking station 450, and
a rechargeable battery 460. The implant system 470 may include an
implant antenna 472, an RF transponder subsystem 473, a power
management subsystem 474, an implant microcontroller
(microprocessor) 476, and a motor interface device 478. The RF
transponder subsystem 473 may include various electronic components
connecting the antenna 472 and the microcontroller 476. For
example, the RF transponder subsystem 473 may include rectifying
circuits and a LTC6900 chip.
[0107] The HID subsystem 420 may include: several input keys
(buttons) 425 for receiving input from a user, a video device (OLED
Display) 427 for outputting visual information to the user, an
audio device 426 for outputting audio information to the user, a
real-time control (RTC) device 424 for monitoring the charge level
of the rechargeable battery 460, an HID microcontroller
(microprocessor) 421 for processing information received from the
keys 425 and the RTC device 424. In order to store and retrieve
various data, the HID subsystem 420 may include several memory
devices, such as a data flash device 428, a serial flash device
422, a SRAM device 423, and an optional EEPROM device 429.
[0108] The RF subsystem 430 may include: an EEPROM device 432 for
storing various data, an RF microcontroller (microprocessor) 431
for performing various tasks requested by the HID microcontroller
421, an RF transponder 434 for driving and receiving information
from the external antenna 440, and a battery management device 436
for interfacing with the docking station 450 and for controlling
the recharging of the battery 460.
[0109] FIGS. 5A-5B show the button configuration and display screen
orientation of a control device 500 according to an embodiment of
the present invention. Generally, the front surface of the control
device 500 may include a display screen 502, a power button
(sensor) 532, a first set of auxiliary buttons (sensors) 504, 506,
and 508, a second set of auxiliary buttons (sensors) 534, 536, and
538, and a set of adjustment control buttons (sensors), such as a
band open button (sensor) 540, a stop adjustment button (sensor)
542, and a band close button (sensor) 544.
[0110] The first and second set of auxiliary buttons 504, 506, 508,
534, 536, and 538 may be configured to adapt to both left-handed
and right-handed users. In one embodiment, for example, the button
configuration and the display screen orientation as shown in FIG.
5A may be used by a left-handed user. Particularly, in the
left-handed configuration (orientation), the first set of auxiliary
buttons 504, 506, and 508 may be inactivated or disabled, whereas
the second set of auxiliary buttons 534, 536, and 538 may serve as
the left, center, and right buttons, respectively.
[0111] In another embodiment, for example, the button configuration
and the display screen orientation as shown in FIG. 5B may be used
by a right-handed user. Particularly, in the right-handed
configuration, the second set of auxiliary buttons 534, 536, and
538 may be inactivated or disabled, whereas the first set of
auxiliary buttons 504, 506, and 508 serve as the right, center, and
left buttons, respectively.
[0112] As the first and second set of auxiliary buttons 504, 506,
508, 534, 536, and 538 are being reconfigured, the display screen
502 may be reoriented as well. When the second set of auxiliary
buttons 534, 536, and 538 are activated, the display screen 502 may
have a first (left-handed) orientation as shown in FIG. 5A. When
the first set of auxiliary buttons 504, 506, and 508 are activated,
the display screen 502 may have a second (right-handed) orientation
as shown in FIG. 5B. Generally, the control device 500 may have a
gyroscopic device (not shown) for sensing its orientation.
Particularly, the control device 500 may use the sensed orientation
to generate one or more signals for reconfiguring the first and
second set of auxiliary buttons 504, 506, 508, 534, 536, and 538,
and for reorienting the display screen 502.
[0113] FIG. 6 shows an exploded view of a control device 600
according to an embodiment of the present invention. The control
device 600 may include a bottom shell 601, a bottom shell lid 602,
a battery pack 603, a left battery holder 604, a right battery
holder 605, a metal plate 606, a magnet 607, a metal pad 608, an RF
PCB 609, a regulatory sticker 610, an RF cable 611, a top shell
612, a bottom shell 613, an adhesive display glass 614, a display
glass 615, an auxiliary buttons group 616, an adjustment control
buttons group 617, a power button 618, a display OLED 619, a Gasket
display 620, and an HID PCB 621. As shown in FIG. 6, the components
of the control device can be grouped as the top shell assembly
(right) and the bottom shell assembly (left). The two assemblies
can be snapped or screen fastened together after the HID PCB 621
and the RF PCB 609 are properly coupled as shown in FIG. 7.
[0114] FIGS. 8A-8R show the sample screen shots of the control
device according to an embodiment of the present invention. In FIG.
8A, the control device may be powered up and it may display a
"Welcome" screen, which include a logo and/or a slogan. In FIG. 8B,
the control device may display the "Code Entering" screen for
receiving authentication information. In the "Code Entering"
screen, a battery strength symbol 801 and a user code request
message 802 may be displayed. Accordingly, a user may enter a
four-digit access code 803. Particularly, the user may use the left
auxiliary button, which may be associated with the plus sign 804,
to increase the value of a digit, the center auxiliary button,
which may be associated with the minus sign 805, to decrease the
digit value, and the right auxiliary button, which may be
associated with the arrow sign 806, to go to the next digit and
eventually to accept the entry.
[0115] In FIG. 8C, the control device may display the "Antenna
Search" screen, in which the user may be instructed to place the
external antenna near the implant antenna. A number of reception
bars 807 may be shown in the "Antenna Search" screen once the
control device detects a nearby implant antenna. The number of
reception bars 807 may indicate the strength of the connection
between the external antenna and the implant antenna. For example,
a signal strength represented by two or less reception bars 807 may
be considered insufficient, whereas a signal strength represented
by three or more reception bars 807 may be considered
sufficient.
[0116] In FIGS. 8D and 8E, the control device may display the
"Loading" screens once the control device detects a signal strength
represented by two or more reception bars 807. The "Loading"
screens may show the progress of downloading the patient's
information from the implant.
[0117] Once the downloading is complete, the control device may
display the "Adjustment" screen (a.k.a. "Default" screen) as shown
in FIG. 8F. In the "Adjustment" screen, the user may adjust the
implanted gastric band. In adjusting the implanted gastric band,
the user may use the band open button, which may be associated with
the band open symbol 812, and the band close button, which may be
associated with the band close symbol 813. Moreover, the user may
choose to perform other functions. In one embodiment, for example,
the user may use the left auxiliary button, which may be associated
with the chart symbol 814, to review the past adjustment history of
a patient. In another embodiment, for example, the user may use the
center auxiliary button, which may be associated with the code
change symbol 815, to change the password (or pass code) of the
control device. In yet another embodiment, for example, the user
may use the right auxiliary button, which may be associated with
the lock symbol 816, to lock the control device.
[0118] When the user presses or selects the open band button, the
control device may display the "Opening" screen as shown in FIG.
8G. In the "Opening" screen, the user may increase the size of the
patient's stoma by loosening the implanted gastric band.
Alternatively, when the user presses or selects the close band
button, the control device may display the "Closing" screen as
shown in FIG. 8H. In the "Closing" screen, the user may decrease
the size of the patient's stoma by tightening the implanted gastric
band. The user may press the stop button to stop the loosening
process or the tightening process to terminate the adjustment
process, after which the "Adjustment" screen may be reloaded.
[0119] When the user selects the chart function, the control device
may display the "Adjustment History Plot" screen as shown in FIG.
8I. In the "Adjustment History Plot" screen, the user may use the
left or center auxiliary button, which may be associated with the
left and right arrow signs 818, to view previous and/or current
records. Alternatively, the user may use the right auxiliary
button, which may be associated with the list symbol 817, to view
the adjustment history list.
[0120] When the user selects the adjustment history list, the
control device may display the "Adjustment History List" screen as
shown in FIG. 8J. In the "Adjustment History List" screen, the user
may use the left or center auxiliary button, which may be
associated with the up and down arrow signs 818, to view previous
and/or current records. Alternatively, the user may use the right
auxiliary button, which may be associated with the forward symbol
819, to return to the "Adjustment History Plot" screen.
[0121] Referring again to FIG. 8F, the user may lock the control
device 110 by selecting the lock symbol 816. When the control
device 110 is locked, the control device may display the "Locked"
screen as shown in FIG. 8K. To exit the "Locked" screen, the user
may press any button except for the power button. Then, the control
device may display the "Code Entering" screen as shown in FIG. 8B.
In the "code entering" screen, the user may be instructed to enter
the pass code again.
[0122] Referring again to FIG. 8F, the user may change the old pass
code by selecting the code change symbol 815. As shown in FIG. 8L,
the control device may display the "Old Code Entering" screen, in
which the user may enter the old pass code. After receiving and
verifying the validity of the old pass code, the control device may
display the "New Code Entering" screen as shown in FIG. 8M. After
receiving the new code 822, the control device may display the
"Confirm or Cancel Code" screen as shown in FIG. 8N. At this point,
the user may select the left auxiliary button, which may be
associated with the OK symbol 804, to accept the new code 822, or
select the right auxiliary button, which may be associated with the
CANCEL symbol 825, to cancel the new code 822. Upon receiving the
confirmation, the control device may display the "Code Changed"
screen as shown in FIG. 80.
[0123] As shown in FIG. 8P, the "Battery Recharge" screen may be
displayed when the control device is being recharged. The
"Adjustment" screen may return once the control device is
disconnected from the docking station. FIGS. 8Q and 8K show the
"Error Message" screens, which may notify the user with warning
messages. For example, the "Error Message" screen may notify the
user when the implant is malfunction or when the battery level is
low.
[0124] Table 1 below may provide a summary of screen shot with
respect to the button functionality.
TABLE-US-00001 TABLE 1 Button assignments for the different screen
shots. Activated Auxiliary Buttons Screen shot Left Center Right
Welcome N/A N/A N/A Code Entering Increase value Decrease value
Next digit Antenna Search N/A N/A N/A Loading N/A N/A N/A
Adjustment History plot Code Change Lock Opening N/A N/A N/A
Closing N/A N/A N/A History Plot Previous point Next point List
History List Scroll up Scroll down Adjustment Locked Code entering
Code entering Code entering Old Code Increase value Decrease value
Next digit New Code Increase value Decrease value Next digit
Confirm Code Confirm N/A Cancel Code Changed N/A N/A Adjustment
Battery Recharge N/A N/A N/A Error Message Adjustment N/A N/A
Warning N/A Adjustment N/A
[0125] Referring to FIG. 9, a schematic view of the HID subsystem
900 is shown according to an embodiment of the present invention.
Generally, the HID subsystem 900 may include eleven device blocks,
such as a microcontroller block 902, a memory block 904, a display
screen block 906, a buzzer and vibrator block 908, a sound
interface block 910, an accelerometer and RTC block 914, an
interface block 918, a USB block 920, an input button block 916, a
JTAG/TRACE connector block 922, and a power supply block 912.
[0126] Referring to FIG. 10, a perspective view of the HID PCB 1000
is shown according to an embodiment of the present invention.
Generally, each of the components on the HID PCB 1000 may be
included in, associated with, or controlled by one of the eleven
device blocks of the HID subsystem 900.
[0127] The microcontroller block 902 may include the
microcontroller device (microprocessor) 1004, which may be
configured as the master of the control device and may control all
the user interface components, such as the display screen, the
buttons, the sound interface, and the memory. The microcontroller
block 902 may also include a crystal oscillator, two pull-down
resistors and a pull-up resistor. The memory block 904 may include
a 128-Mb flash memory 1034 and a 1-Mb EEPROM 1046, along with five
pull-up resistors and four regulating capacitors.
[0128] The display screen block 906 may include an OLED display, an
OLED display flat connector 1048 and a display driver supply (not
shown). The buzzer and vibrator block 908 may include various
components for driving a buzzer 1038 and a vibrator 1008. The sound
interface block 910 may include an audio power amplifier 1010,
which may be connected to the speaker (not shown). The
accelerometer and RTC block 914 may include an RTC chip 1041 and a
PC30 accelerometer chip 1035 as well as a lithium ion battery 1044
for back-up power.
[0129] The input button block 916 may include a power button (not
shown) for sending power up signals to the HID PCB and the RF PCB.
The input button block 916 may also include two set of triplet
buttons (auxiliary buttons) selectable by three output keys. The
interface block 918 may include two connectors 1050 and 1052 for
connecting cards together and for connecting between RF PCB. The
USB block 920 may include two mini USB connectors 1020 and 1030, an
ESD input protection chip (not shown), and an RS232 translator chip
FT232RL (not shown). The JTAG block 922 may include two connectors
(not shown). Finally, the power block 912 may comprise a 3.3V
voltage regulator (not shown) and several 3.3V power
connections.
[0130] Referring to FIG. 11, a schematic view of the RF subsystem
1100 is shown according to an embodiment of the present invention.
Generally, the RF subsystem 1100 may include seven device blocks,
such as a main controller block 1104, a modulation block 1106, a
demodulation block 1108, an auxiliary controller block 1110, an RF
power supplies block 1112, a system power block 1101, and a battery
block 1102.
[0131] Referring to FIG. 12, a perspective view of the RF PCB 1200
is shown according to an embodiment of the present invention.
Generally, each of the components on the HID PCB 1200 may be
included in, associated with, or controlled by one of the seven
device blocks of the RF subsystem 1100.
[0132] The RF main controller block 1104 may include a
microcontroller (processing device) 1201, which may perform as a
slave to the HID microcontroller block 902. The RF microcontroller
1201 may control the power induction in the implant, the charging
circuitry in the docking station, the communication to and from the
implant, and the communication with the HID microcontroller block
902. The RF microcontroller 1201 may further receive multiple
monitoring inputs and the reset command from the HID
microcontroller block 902. The USB connection may be established
through a mini USB connector 1274 with the USB protocol translated
into a UART serial interface through an RS232 translator chip (not
shown).
[0133] The modulation block 1106 may include a class E amplifier
1234 for generating an amplitude modulation signal with carrier
frequency at about 27 MHz. Particularly, the modulation block 1106
may be involved in generating a 27 MHz carrier frequency with an
amplitude that equals the RF supply voltage VSUP, while the data
signal may contain the digital command being sent to the implant
via the external antenna.
[0134] The demodulation block 1108 may include a FM demodulator
chip 1208 to demodulate the signals received from the implant and
extracted from the external antenna via a directional coupler 1272.
As such, the FM demodulator chip 1208 may be used for retrieving
useful information, such as the received signal strength RSSI and
the feedback message from the implant. The RF demodulator chip 1208
may also generate regulating signals, including REG_LEVEL,
VSUP_CTRL, VSUP, and FORCE_RF_LEVEL.
[0135] The power supplies block may comprise a LT1961 voltage
regulator (not shown), the amplitude of which may be controlled by
either the VSUP_CTRL input indirectly from the implant or the DAC
IN input from the RF controller. The VSUP_CTRL input helps
implement the control loop between the implant and the control
device which adjusts the power induced in the implant. The RF
microcontroller 1201 may also shutdown VSUP through the VSUP_ON/OFF
input. Moreover, VSUP_INHIBIT1 may shutdown VSUP whenever the
control device is powered from an external source to avoid any
danger to the patient from power line surges. BSUP_INHIBIT2 may
provide another shutdown path from the auxiliary controller
block.
[0136] The auxiliary controller block 1110 may include an auxiliary
controller 1244 and the associating connectors. The auxiliary
controller 1244 may allow the overall system to implement a
software oriented version of the implant power induction
control.
[0137] The system power block 1101 may comprise the LM22672M
voltage regulator 1256 for regulating the power supplies at 3.6V,
the LP2985-33 voltage regulator U18 1276 for regulating the power
supplies at 3.3V, and several monitoring signals indicating the
power being turned on (KON), the presence of external power
(EXTPWR_PRESENT) and the current load to the battery (ILOAD). The
battery block 1102 may include a battery management related
circuitry 1268, the battery connectors 1246 and 1264, as well as
two batteries connected in series, which may be monitored by the
signals BATMON, BATMONZ, BATT_TH, EXT_BAT_MES1 and
EXT_BAT_MES2.
[0138] The discussion now turns to the power regulation subsystem
of the remotely adjustable remotely power (RARP) gastric band
system. Referring to FIG. 13, a schematic view of a power
regulation subsystem 1300 is shown according to an embodiment of
the present invention. Generally, the power regulation subsystem
1300 may be implemented by various devices (blocks) of the RF Board
and of the Implant. The RF Board may include a modulation device
(block) 1320, an external antenna 1324, a demodulation device
(block) 1330, a power supply device (block) 1340, and a controller
device (block) 1310. The Implant may include an implantable antenna
1352, a rectifying device (first device block) 1350, a maximum
power sensing device (second device block) 1360, a regulation
device (third device block) 1370, and an impedance switching device
(fourth device block) 1380.
[0139] To initiate the power induction process, the controller
device 1310 may send a transmission signal 1312 to enable the
modulation device 1320. Depending on the operation mode of the RF
Board, the transmission signal 1312 can be activation based or
interrupt based. After being enabled, the modulation device 1320
may generate an amplitude modulation signal for driving the
external antenna node 1322. The external antenna node 1322 may be a
transmission line that couples between the external antenna 1324
and the modulation device 1320. As a result, the external antenna
1324 may transmit a telemetric signal 1326 according to the
amplitude modulation signal.
[0140] The telemetric signal 1326 may travel across air and
penetrate the body tissue of the patient, such that it may be
received by the implantable antenna 1352. Based on the principles
of electromagnetic induction, an alternate current (AC) may be
induced at the implant antenna node 1354. The rectifying device
1350 may rectify the voltage associate with the alternate current,
so as to deliver a DC input voltage (V.sub.IN) on the DC input
voltage (V.sub.IN) node 1356. The maximum power sensing device 1360
may monitor the level of the DC input voltage V.sub.IN. When the DC
input voltage V.sub.IN exceeds a certain predetermined threshold
voltage value, the maximum power sensing device 1360 may generate a
regulation signal 1362 to activate the regulation device 1370.
[0141] After being activated, the regulation device 1370 may
generate a regulation voltage 1372. The magnitude of which may
depend on a voltage difference (potential difference) between the
DC input voltage V.sub.IN and the predetermined threshold voltage
value. Thus, the magnitude of the regulation voltage 1372 may
represent or indicate the amount of regulation that may be needed.
Generally, the DC input voltage V.sub.IN may be a function of a
transmission distance between the external antenna 1324 and the
implantable antenna 1352. When the transmission distance decreases,
the signal strength of the telemetric signal 1326 may increase,
thereby causing the DC input voltage V.sub.IN to rise. Thus, as the
external antenna 1324 approaches the implantable antenna 1352, the
regulation voltage 1372 may increase. In order to communicate the
need to regulate with the RF Board, the regulation voltage 1362 may
be used for generating one or more feedback signals and/or
messages.
[0142] The impedance switching device (switching device) 1380 may
receive and process the regulation voltage 1362. After processing
the regulation voltage 1362 along with other signals, the impedance
switching device 1380 may couple and decouple the DC input voltage
V.sub.IN node 1356 to and from an additional impedance component at
a feedback frequency. Generally, the feedback frequency may be
determined based on the regulation voltage 1362 and some other
factors. In one embodiment, for example, the feedback frequency may
be inversely proportional to the regulation voltage 1362. In
another embodiment, for example, the feedback frequency may be
directly proportional to the regulation voltage 1362.
[0143] By switching on and off the additional impedance component,
the impedance switching device 1380 may generate a feedback signal
1382, which may superimpose the regular DC input voltage V.sub.IN.
That is, the overall load impedance (Z.sub.LOAD) may be adjusted by
the feedback frequency of feedback signal 1382.
[0144] According to the principle of mutual inductance, the
fluctuation of the overall load impedance and/or the feedback
signal 1382 may manifest as a passive telemetric signal 1356, which
may be received by the external antenna 1324. Consequently, the
feedback frequency of the feedback signal may be seen as a message
(envelop) frequency of the passive telemetric signal 1357.
[0145] In order to separate the passive telemetric signal 1357 from
the outbound amplitude modulation signal, the RF Board may use a
sensing device (block) 1332 to sense or extract a feedback profile
1334 of the passive telemetric signal 1357 from the external
antenna node 1322. The feedback profile 1334 may have a frequency
tracking the feedback frequency of the feedback signal. In one
embodiment, for example, the sensing device 1332 may be a
directional coupler. The demodulation device 1330 may receive the
feedback profile 1334 and determine and/or extract the message
frequency embedded in the feedback profile 1334.
[0146] Consequentially, the demodulation device 1330 may generate a
voltage supply control signal 1336 based on the feedback frequency.
The power supply device 1340 may process the voltage supply control
signal 1336 and regulate the RF supply voltage 1342 accordingly.
Because the modulation device 1320 may be powered by the RF supply
voltage 1342, the amplitude modulation signal may be indirectly
regulated by the power supply device 1340. As a result, the power
induced by the amplitude modulation signal may be increased or
decreased depending on the feedback signal 1382.
[0147] More specifically, the amplitude modulation signal may have
a carrier frequency and a magnitude (modulation amplitude).
Depending on the load impedance, the carrier frequency may be
selected from a range of radio frequencies (about 30 kHz to about
300 GHz) for maximum power transfer. For example, the carrier
frequency may be about 27 MHz when the load impedance is about
50.OMEGA..
[0148] The modulation amplitude may be controlled by the RF supply
voltage 1342, and it may determine the amount of power being
transferred from the RF Board to the implant. Thus, power transfer
may be regulated by adjusting the modulation amplitude, which may
depend on the RF supply voltage 1342. For example, when the implant
receives excessive power, which may cause overheating in the
implant, the RF supply voltage 1342 may be lowered to reduce the
modulation amplitude of the amplitude modulation signal. For
another example, when the implant receives insufficient power,
which may cause the implant to be turned off, the RF supply voltage
1342 may be augmented to increase the modulation amplitude of the
amplitude modulation signal.
[0149] In FIG. 14, a schematic view of a modulation device 1400 is
shown according to an embodiment of the present invention.
Generally, the modulation device 1400 may be used for implementing
the functional features of the modulation device 1320.
Particularly, the modulation device 1400 may include an activation
block (activation device path) 1430 for enabling or disabling the
generation of the amplitude modulation signal, an oscillating
device 1450 for generating a carrier frequency signal 1452, and a
class E amplifier block (amplifier device path) 1410 for generating
the amplitude modulation signal 1420. The oscillating device 1450
may be a crystal oscillator, and it may be used for controlling the
carrier frequency of the amplitude modulated signal 1420.
[0150] The activation block 1430 may include a first stage
amplifier 1432 for amplifying the transmission signal 1312, and a
second stage amplifier 1434 for generating a data override signal
1436. Generally, the carrier frequency signal 1452 may be buffered
by a first stage inverter 1453 and a second stage inverter 1454.
Although the first stage inverter 1453 may be powered on by a
separate power source, the second stage inverter 1454 may be
enabled or disabled by the data override signal 1436.
[0151] When the RF Board is powering the implant, the data override
signal 1436 may be low, such that the carrier frequency signal 1452
may drive a switching node 1401. Alternatively, when the RF Board
is transmitting data, the data override signal 1436 may be high,
such that the second inverter stage 1454 may be turned off
momentarily during data transmission. As a result, the carrier
frequency signal 1452 may be blocked from driving the switching
node 1401.
[0152] The class E amplifier block 1410 may have a common source
stage 1404 for driving a first intermediate node 1402. The output
of the common source stage 1404 may have a frequency component,
which may be controlled by the carrier frequency signal 1452 of the
oscillating device 1450, and an amplitude component, which may be
controlled by the RF supply voltage 1342. Depending on the
regulation level, the amplitude component may change as the
transmission distance varies. In one embodiment, for example, the
amplitude component may range from about 3 V to about 16 V. In
another embodiment, for example, the amplitude component may range
from about 5V to about 14 V. As discussed earlier, the power
induced in the Implant may be regulated by adjusting the amplitude
component of the amplitude modulation signal 1420, which may be
dictated by the RF supply voltage 1342.
[0153] Referring to FIG. 15, the class E amplifier block 1410 may
have a relatively low sensitivity to any variation in the load
Z.sub.L, and it may have a high efficiency as long as the
transitions at the(common source state) MOS switch 1404 occur while
the current or the voltage is null. Referring to FIG. 16, the
capacitor C2 and the impedance Zh2 may be the adjustable components
in the amplifier block 1410, such that the transition point may be
moved left and/or right by adjusting the value of the capacitor C2,
and it may be moved up and/or down by adjusting the value of the
impedance Zh2.
[0154] In FIG. 17, a schematic view of a rectifying device 1700 is
shown according to an embodiment of the present invention.
Generally, the rectifying device 1700 may implement the functional
features of the rectifying device 1350 as discussed in FIG. 13.
Particularly, the rectifying device 1700 may include a first
capacitor 1712, a second capacitor 1714, a first diode 1722, and a
second diode 1724. More specifically, the first and second
capacitors 1712 and 1714 may function as a pair of charge storage
(or bootstrap) devices, while the first and second diodes 1722 and
1724 may function as a pair of voltage directing devices.
[0155] The modulation device 1320 may drive the external antenna
1324 with an amplitude modulation signal 1701, which may generate
an alternate current in the external antenna 1324. As a result,
electromagnetic waves may be emitted from the external antenna
1324, and they may propagate through air and penetrate the body
tissue of the patient. A small portion of the electromagnetic waves
may be absorbed by a secondary parasite 1704, while a large portion
of the electromagnetic waves may induce alternate voltage 1703 in
the implantable antenna 1352.
[0156] The amplitude of the induced voltage 1703 may be affected by
a transmission distance 1720 separating the external antenna 1324
and the implantable antenna 1352. For example, the amplitude of the
induced voltage 1703 may decrease when the transmission distance
1720 increases from 10 mm to 20 mm. For another example, the
amplitude of the induced voltage 1703 may increase when the
transmission distance 1720 decreases from 35 mm to 20 mm.
[0157] The induced voltage 1703 may be rectified by the first and
second diodes 1722 and 1724. As a result, the output nodes 1730 of
the rectifying device 1700 may deliver the DC input voltage
(V.sub.IN) 1705. The two-diode configuration may allow the V.sub.IN
to have a relatively high magnitude, which may be slightly less
than two times of the induced voltage 1703. When the transmission
distance 1702 is large (e.g. greater than 35 mm), it is
advantageous to have the relative high magnitude V.sub.IN to
compensate the energy loss to the secondary parasite 1704. However,
when the transmission distance 1702 is small (e.g. less than 10
mm), the relative high magnitude V.sub.IN may be problematic
because it may produce excessive energy, which may lead to
overheating within the implant.
[0158] To prevent overheating, the Implant may include a power
regulation subsystem to provide feedback information to adjust the
output energy of the modulation device. In FIG. 18, an implant
power regulation subsystem (a.k.a. the power system) 1800 is shown
according to an embodiment of the present invention. Generally, the
implant power regulation subsystem 1800 may include the maximum
power sensing device (second device block) 1360, the regulation
device (third device block) 1370, and the impedance switching
device (fourth device block) 1380.
[0159] The maximum power sensing device 1360 may include a Zener
diode 1862 and a first pull down resistor 1844. In one
configuration, the positive terminal of the Zener diode 1862 may be
coupled to the DC input voltage (V.sub.IN) node and the negative
terminal of the Zener diode 1862 may be coupled to the first pull
down resistor 1844, which may be coupled to an internal ground
node. The Zener diode 1862 may have a breakdown voltage V.sub.BD
across its positive and negative terminals. When the DC input
voltage (V.sub.IN) is less than the breakdown voltage V.sub.BD, the
Zener diode 1862 may be under forward bias, such that the Zener
diode 1862 is unlikely to sink any current from the DC input
voltage (V.sub.IN) node. As a result, the first pull down resistor
1864 may pull the regulation signal to ground.
[0160] However, when the DC input voltage (V.sub.IN) reaches and/or
exceeds the breakdown voltage V.sub.BD, the Zener diode 1862 may be
under reverse bias, such that the Zener diode 1862 may begin to
draw a breakdown current I.sub.BD from the DC input voltage
(V.sub.IN) node. As a result, the regulation signal 1362 may
maintain a voltage level V.sub.R across the first pull down
resistor 1864. Depending on the design goal, the breakdown voltage
V.sub.BD may be predetermined to accommodate the power consumption
of the implant. That is, the breakdown voltage V.sub.BD may be
chosen at a range that is substantially equal to or close by the
predetermined threshold voltage. In one embodiment, for example,
the breakdown voltage V.sub.BD may be about 3 V. In another
embodiment, for example, the breakdown voltage V.sub.BD may be
about 7 V. In yet another embodiment, for example, the breakdown
voltage V.sub.BD may be about 5.6 V.
[0161] Although the sinking of the breakdown current I.sub.BD may
have little effect on the V.sub.IN value, it may help generate the
regulation signal 1362. The voltage level V.sub.R of the regulation
signal 1362 may indicate or represent a desirable level of
regulation. Mainly, the breakdown current I.sub.BD may be highly
sensitive to the change of V.sub.IN value, so that the regulation
signal voltage level V.sub.R may track closely to the amount of the
excessive DC input voltage V.sub.IN.
[0162] The regulating device 1370 may include a voltage regulator
1872, a first pull up resistor 1874, a second pull up resistor
1875, a transistor 1876, and a second pull down resistor 1878. The
voltage regulator 1872 may be used for generating a relatively
constant local voltage V.sub.CC at a first node (e.g., the V.sub.CC
node). The constant local voltage V.sub.CC may supply power to
various electronic components of the implant. For example, the
local voltage V.sub.CC may supply power to the current path formed
partially by the first and second pull up resistors 1874 and 1875.
Generally, the local voltage V.sub.CC may be less than the DC input
voltage V.sub.IN and the predefined threshold voltage, which may be
approximated by the breakdown voltage V.sub.BD of the Zener diode
1862.
[0163] When the regulation signal voltage level V.sub.R is less
than the threshold voltage of the transistor 1876, there may be
little or no regulation current I.sub.R because the transistor 1876
is not conducting. As such, the regulation voltage V.sub.REG may be
substantially equal to the local voltage V.sub.CC
[0164] However, when the DC input voltage V.sub.IN exceeds the
breakdown voltage V.sub.BD of the Zener diode 1862, the regulation
signal voltage level V.sub.R may begin to rise, and eventually, it
may overcome the threshold voltage of the transistor 1876. As a
result, the transistor 1876 may be turned on and draw the
regulation current I.sub.R. The regulation current I.sub.R may
cause a potential drop across the first pull up resistor 1874,
which is connected between the first node and a second node (e.g.,
the V.sub.REG node). Consequently, the regulation voltage V.sub.REG
may decline as the regulation signal voltage level V.sub.R
increase. With the help of the pull up resistor 1874, the
regulation current I.sub.R creates a regulation margin (i.e.,
potential difference) between the V.sub.CC node and the V.sub.REG
node.
[0165] From the point where the transistor 1876 begins to conduct
to the point where the transistor 1876 becomes saturated, the
regulation voltage V.sub.REG may achieve substantial linearity with
the regulation signal voltage V.sub.R, which may be driven
primarily by the breakdown current I.sub.BR. As such, the
regulation device 1370 may perform the power regulation task when
the DC input voltage V.sub.IN exceeds the breakdown voltage
V.sub.BD by a regulation margin. The regulation margin may be
represented by the voltage level V.sub.R of the regulation signal
1362. In one embodiment, for example, the regulation margin may
range from about 0.05 V to about 10V. In another embodiment, for
example, the regulation margin may range from about 0.1 V to about
5V. In yet another embodiment, for example, the regulation margin
may range from about 1 V to about 3 V.
[0166] The transistor 1876 may amplify the regulation margin
between the DC input voltage and the predefined threshold. As such,
the potential difference between the local voltage V.sub.CC and the
regulation voltage V.sub.REG may be highly responsive and sensitive
to any slight change in the regulation margin.
[0167] After the regulation voltage V.sub.REG begins to decline,
the impedance switching device 1380 may be activated. Generally,
the impedance switching device 1380 may include a frequency
modulation device (block) 1820, a switch 1840, and an impedance
component 1844. The frequency modulation device 1880 may generate a
frequency modulation signal 1822. The frequency modulation signal
1822 may have a modulated frequency that is based on and/or
represent the value of the regulation voltage V.sub.REG. In one
embodiment, for example, the modulated frequency of the frequency
modulation signal 1822 may be directly proportional to the
potential difference between the local voltage V.sub.CC and the
regulation voltage V.sub.REG. In another embodiment, for example,
the modulated frequency of the frequency modulation signal 1822 may
be inversely proportional to the potential difference between the
local voltage V.sub.CC and the regulation voltage V.sub.REG. In any
event, the feedback signal as discussed in FIG. 13 may include the
frequency modulation signal 1822.
[0168] The frequency modulation signal 1822 may be used for turning
on and off the switch 1840. According to the modulated frequency of
the frequency modulation signal 1822, the impedance component 1844
may be periodically connected to and disconnected from the DC input
voltage (V.sub.IN) node. The impedance component 1844 may act as an
additional load and in the form of a pull down device. Because
additional switching current I.sub.Z is sunk by the impedance
component 1844, the DC input voltage V.sub.IN may drop and rise at
the modulated frequency of the frequency modulation signal
1822.
[0169] As a result, the profile of the DC input voltage V.sub.IN
may be superimposed by the profile of the frequency modulation
signal 1822. The superimposed V.sub.IN profile may become a
modulated amplitude (e.g., the message envelop) of the passive
telemetric signal 1357. As a result, the switch 1840 may transform
the frequency modulation signal 1822 to a frequency modulated
amplitude modulated signal, such as the passive telemetric signal
1357. The passive telemetric signal 1357 may be received and
demodulated by the RF Board as part of the power regulation
process.
[0170] Referring to FIG. 19, various waveforms of the implant power
regulation subsystem 1800 are shown according to an embodiment of
the present invention. Initially, the voltage across the Zener
diode 1862 (V.sub.ZENER) may increase linearly and track the DC
input voltage V.sub.IN when the DC input voltage V.sub.IN is less
than the breakdown voltage V.sub.BD. As such, the breakdown current
I.sub.BD may be kept at minimum and the regulation signal voltage
level V.sub.R may be close to ground.
[0171] Because the regulation signal voltage level V.sub.R does not
overcome the threshold voltage of the transistor 1876, there may be
minimum or no regulation current I.sub.R flowing through the first
and second pull down resistors 1874 and 1875. As a result, the
regulation voltage V.sub.REG may track closely to the local voltage
V.sub.CC. Since V.sub.CC may be set a voltage level (e.g. 5 V)
lower than the breakdown voltage V.sub.BD (e.g. 5.6 V), the
regulation voltage VREG may be saturated before the regulation
mechanism is triggered. At this stage, the impedance component 1844
may be decoupled from the V.sub.IN node, such that only minimum or
no switching current I.sub.Z may be sunk from the V.sub.IN
node.
[0172] When the DC input voltage V.sub.IN begins to exceed the
breakdown voltage V.sub.BD, the Zener diode 1862 may begin to
conduct the breakdown current I.sub.BD. As a result, the regulation
signal voltage level V.sub.R may begin to rise and it may
eventually overcome the threshold voltage of the transistor 1876.
From the point when the transistor 1876 begins to conduct the
regulation current I.sub.R to the point when the transistor 1876
becomes saturated (i.e. maximum I.sub.R), the power regulation
subsystem 1800 may be under rapid regulation. That is, the
regulation voltage V.sub.REG may be highly sensitive to the
slightest increase in the DC input voltage V.sub.IN.
[0173] As the regulation current I.sub.R increases, the regulation
voltage V.sub.REG may begin to decline, which may cause the
frequency modulation device 1820 to generate the frequency
modulation signal 1822. Driven by the frequency modulation signal
1822, the switch 1840 may cause the impedance component 1844 to be
coupled to or decoupled from the V.sub.IN node. Accordingly, the
switching current I.sub.Z may share the frequency of the frequency
modulation signal 1840. As discussed earlier, the frequency of the
frequency modulation signal 1840 may be inversely proportional to
the difference between the local voltage V.sub.CC and the
regulation voltage V.sub.REG. Hence, the frequency of the frequency
modulation signal 1840, which may be represented by the profile of
the switching current I.sub.Z, may decrease as regulation voltage
VREG drops further away from local voltage V.sub.CC.
[0174] The discussion now turns to a double modulation scheme
adopted by the Implant in providing feedback information to the RF
Board. The feedback information may include the value of the
regulation voltage V.sub.REG and/or the patient's biometrics data.
Generally, the Implant may include a memory device for storing the
patient's biometrics data, such as the patient's identity and event
records pertinent to the patient's gastric band adjustment history.
Among other information, each of the event records may record the
current gastric band position and the adjustment date. It is
desirable that the Implant may telemetrically transmit various
pieces of feedback information in a compact and efficient
manner.
[0175] In FIG. 20, waveforms of a double modulation (frequency
modulated amplitude modulation) scheme are shown according to an
embodiment of the present invention. Initially, there may be a data
signal 2010 to be transmitted from the Implant to the RF Board. The
data signal 2010 may have a high state 2012 and a low state 2014,
each of which may represent one of the binary states. For example,
the data signal 2010 may have the high state 2012 during time
period (TP) 1, the low state 2014 during TP 2, the high state 2012
during both TP 3 and TP 4, and the low state 2014 during TP 5.
[0176] Next, a frequency modulation may be applied to the digital
signal 2010 to form a frequency modulation signal 2020. Generally,
the frequency modulation may be performed by the frequency
modulation device 1820 or any other similar devices, such as a
LTC6900 chip. The frequency modulation signal 2020 may have one or
more modulated frequencies, such as a first (low) frequency 2022
and a second (high) frequency 2024. Depending on the assignment
scheme, the first and second frequencies 2022 and 2024 may be
assigned to one of the low state 2012 or the high state 2024 of the
data signal 2010.
[0177] In the present case, for example, the first frequency 2022
may be assigned to the high state 2012, and the second frequency
2024 may be assigned to the low state 2024. Accordingly, the
frequency modulation signal 2020 may have the first frequency 2022
during TP 1, the second frequency 2024 during TP 2, the first
frequency 2022 during TP 3 and TP 4, and the second frequency 2022
during TP 5.
[0178] The frequency modulation signal 2020 may be used for
encoding two or more signals simultaneously. In one embodiment, for
example, the frequency modulation signal 2020 may be used for
encoding two digital signals with four logic states. As such, the
frequency modulation signal 2020 may have four frequency levels
assigned to the four logic states. In another embodiment, for
example, the frequency modulation signal 2020 may be used for
encoding three digital signals with eight logic states.
Accordingly, the frequency modulation signal 2020 may have eight
frequency levels assigned to the eight logic states.
[0179] In yet another embodiment, for example, the frequency
modulation signal 2020 may be used for encoding one digital signal
and one analog signal. The digital signal may carry feedback
information regarding the patient's biometrics. The analog signal
may carry feedback information regarding the value of the
regulation voltage V.sub.REG. Accordingly, the frequency modulation
signal 2020 may have a first frequency band and a second frequency
band. Particularly, the high state of the digital signal and the
spectrum of the analog signal may be jointly represented by the
first frequency band, while the low state of the digital signal and
the spectrum of the analog signal may be jointly represented by the
second frequency band.
[0180] After the frequency modulation signal 2020 is generated, it
may be combined, mixed, or superimposed with the original amplitude
modulated carrier to form a frequency modulated amplitude
modulation signal 2030. The original amplitude modulated carrier
may be originated from the RF Board, and it may retain its carrier
frequency at the implant antenna. As such, the frequency modulated
amplitude modulation signal 2030 may have a common carrier
frequency and a message frequency. The common carrier frequency may
be constant throughout the entire transmission period, while the
message (envelop) frequency may track closely to the first and
second frequencies 2022 and 2024 of the frequency modulation signal
2020. Accordingly, the frequency modulated amplitude modulation
signal 2030 may have a first message(envelop) frequency 2032 during
TP 1, a second message (envelop) frequency 2034 during TP 2, and
the first message frequency 2032 during TP 3.
[0181] Using the frequency modulated amplitude modulation signal
2030 to provide feedback information may provide several
advantages. For example, the transmission of the frequency
modulated amplitude modulation signal 2030 may consume very little
energy from the Implant because it may take advantage of the
original amplitude modulation signal and it may be passively
transmitted. For another example, the intermediate frequency
modulation scheme may allow multiple pieces of information to be
transmitted simultaneously, thereby increasing the transmission
efficiency and shortening the total transmission time. For another
example, the frequency modulated amplitude modulation signal 2030
may only require one communication channel. As such, the external
antenna and the implant antenna may be transferring power and
communicating at the same time. For yet another example, the
frequency modulated amplitude modulation signal 2030 may have a
high tolerance to parasitic noise. Mainly, the underlying
information may be encoded in different frequency levels and/or
frequency bands, which may be highly resistive to distortion caused
by parasitic noise.
[0182] FIG. 21 shows a schematic view of a double modulation
subsystem 2100 according to an embodiment of the present invention.
Generally, the double modulation subsystem 2100 may help generate
the feedback signal for communicating the value of the regulation
voltage V.sub.REG to the RF Board. As such, the double modulation
subsystem 2100 may be used as a communication system and in
conjunction with the power regulation subsystem 1800.
[0183] The double modulation subsystem 2100 may include a frequency
modulation device 2120, an output transistor 2150, a data switch
2112, a voltage regulation resistor R.sub.REG, a data resistor
R.sub.CMD, and a bias resistor R.sub.BO. The frequency modulation
device 2120 may have similar functional features as the frequency
modulation device 1820. Moreover, the frequency modulation device
2120 may adjust a switching frequency (f.sub.SW) of the frequency
modulated signal 1822 according to the regulation voltage and the
status of the data switch 2112.
[0184] The data switch 2112 may be used for generating serial data
signals similar to the data signal 2010 as shown in FIG. 20. More
specifically, the data switch 2112 may be controlled by the implant
microcontroller 476 (previously shown in FIG. 4), which may encode
various information to the data signal. In one embodiment, for
example, the implant microcontroller may encode the patient's
identification information to the data signal. In another
embodiment, for example, the implant microcontroller may encode the
patient's gastric band adjustment record to the data signal. In yet
another embodiment, for example, the implant microcontroller may
encode a handshake confirmation message to the data signal.
[0185] The frequency modulation device 2120 may be implemented by a
LTC 6900 chip or other equivalent devices. From a functional
standpoint, the frequency modulation device 2120 may determine the
switching frequency according to the local voltage V.sub.CC, a set
voltage V.sub.SET and an input current I.sub.RES. Similar to the
power system as shown in FIG. 18, the regulation voltage V.sub.REG
may be generated by the regulation device 1370 at a first node
(e.g., the V.sub.REG node). The set voltage V.sub.SET at a second
node (e.g., the V.sub.SET node) may be controlled by a data path,
which may include the data switch 2112 and the command resistor
R.sub.CMD. Moreover, the voltage regulator 1872 may generate the
local voltage V.sub.CC at a third node (e.g., the V.sub.CC node).
The local voltage V.sub.CC may perform as a current source for the
pull up resistor 1874 and the data path.
[0186] In one embodiment, the frequency modulation device 2120 may
include a differential amplifier 2132, a pass transistor 2134, and
an oscillator 2140. The differential amplifier 2132 may generate an
input differential voltage V.sub.DIFF by amplifying the potential
difference between the local voltage V.sub.CC and a set voltage
V.sub.SET (i.e. V.sub.CC-V.sub.SET). The pass transistor 2134 may
be biased by a bias voltage V.sub.BIAS to pass the input current
I.sub.RES from the V.sub.SET node to the oscillator 2140. After
receiving the input differential voltage V.sub.DIFF and the input
current I.sub.RES, the oscillator 2140 may generate the frequency
modulation signal 1822 with the switching frequency f.sub.SW, which
may be modeled by Equation 1:
f sw = 1 MHz .times. 20 k .OMEGA. .times. I RES ( V CC - V SET ) .
##EQU00001##
[0187] Generally, the input current I.sub.RES may be a summation of
several currents joining at the V.sub.SET node. For example, when
the data switch 2112 is closed, it may conduct a data current
(I.sub.CMD) from the V.sub.CC node to the V.sub.SET node. The data
current I.sub.CMD may be characterized as
(V.sub.CC-V.sub.SET)/R.sub.REG. For another example, a regulation
current I.sub.REG may be conducted across the regulation resistor
R.sub.REG. The magnitude of the regulation current I.sub.REG may
depend on the level of regulation, such that it may range from
(V.sub.CC-V.sub.SET)/R.sub.REG to about
0.5*(V.sub.CC-V.sub.SET)/R.sub.REG. For yet another example, a bias
current I.sub.BO may be conducted across the bias resistor
R.sub.BO, and it may be characterized as
(V.sub.CC-V.sub.SET)/R.sub.BO.
[0188] When the data signal is at a low state (i.e. data switch
2112 closed) and when there is no power regulation, the switching
frequency may be modeled by Equation 2, which recites:
f SW , LL , NR = 1 MHz .times. 20 k .OMEGA. .times. ( 1 R BO + 1 R
REG + 1 R CMD ) . ##EQU00002##
[0189] When the data signal is at a high state (i.e. data switch
2112 open) and when there is no power regulation, the switching
frequency may be modeled by Equation 3, which recites:
f SW , HL , NR = 1 MHz .times. 20 k .OMEGA. .times. ( 1 R BO + 1 R
REG ) . ##EQU00003##
[0190] When the data signal is at a low state and when there is
maximum power regulation, the switching frequency may be modeled by
Equation 4, which recites:
f SW , LL , MR = f SW , LL , NR - 1 MHz .times. 10 k .OMEGA.
.times. ( V CC R REG .times. ( V CC - V SET ) ) . ##EQU00004##
[0191] When the data signal is at a high state and when there is
maximum power regulation, the switching frequency may be modeled by
Equation 5, which recites:
f SW , HL , MR = f SW , HL , NR - 1 MHz .times. 10 k .OMEGA.
.times. ( V CC R REG .times. ( V CC - V SET ) ) . ##EQU00005##
[0192] When the data signal is at a low state and when the
regulation voltage is at V.sub.REG, the switching frequency may be
modeled by Equation 6, which recites:
f SW , LL , VR = f SW , LL , NR - 1 MHz .times. 20 k .OMEGA.
.times. ( V CC - V REG R REG .times. ( V CC - V SET ) ) .
##EQU00006##
[0193] For low output level and regulation voltage at V.sub.REG,
the switching frequency may be modeled by Equation 7, which
recites:
f SW , HL , VR = f SW , HL , NR - 1 MHz .times. 20 k .OMEGA.
.times. ( V CC - V REG R REG .times. ( V CC - V SET ) ) .
##EQU00007##
[0194] As persons skilled in the art may readily appreciate, the
value of the swing frequency f.sub.SW may depend on the resistances
of the various resistors, which may be adjusted to meet various
design goals. In one embodiment, for example, the resistance of the
bias resistor R.sub.BO may be about 29.43 k.OMEGA.. In another
embodiment, for example, the resistance of the regulation resistor
R.sub.REG may be about 1 M.OMEGA.. In yet another embodiment, for
example, the resist R.sub.CMD may be about 430 k.OMEGA.. Moreover,
V.sub.CC may be set at about 5V, such that V.sub.SET may be at
about 3.9V.
[0195] Accordingly, the swing frequency f.sub.SW,LL,NR may be about
746 kHz, the swing frequency f.sub.SW,HL,NR may be about 699.5 kHz,
the swing frequency f.sub.SW,LL,MR may be about 700.5 kHz, and the
swing frequency f.sub.SW,HL,MR may be about 654 kHz. Furthermore,
the swing frequency f.sub.SW,LL,VR may range from about 746 kHz to
about 700.5 kHz, while the swing frequency f.sub.SW,HL,VR may range
from about 699.5 kHz to about 654 kHz.
[0196] Referring to FIG. 22, a frequency chart of the double
modulation scheme is shown according to the above parameters. With
a binary data signal, the double modulation scheme may include a
low state band 2202 and a high state band 2204. The low state band
2202 may represent the range of swing frequencies that may be
assigned to the low state value of the data signal. Similarly, the
high state band 2204 may represent the range of swing frequencies
that may be assigned to the high state value of the data signal.
Because the swing frequency may incorporate or embedded with power
regulation information, each of the low and high state bands 2202
and 2204 may have a maximum swing frequency (i.e. f.sub.SW,LL,NR
and f.sub.SW,HL,NR) for representing a no-regulation scenario, a
transient swing frequency (i.e. f.sub.SW,LL,VR and f.sub.SW,HL,VR)
for representing a rapid regulation scenario, and a minimum swing
frequency (i.e. f.sub.SW,LL,MR and f.sub.SW,HL,RM) for representing
a maximum-regulation scenario.
[0197] Although FIG. 22 shows only two swing frequency bands, the
frequency modulation device 2100 may provide two or more swing
frequency bands. In one embodiment, for example, the frequency
modulation device 2100 may provide four swing frequency bands for
encoding two binary data signals. In another embodiment, for
example, the frequency modulation device 2100 may provide eight
swing frequency bands for encoding three binary data signals. In
yet another embodiment, for example, the frequency modulation
device 2100 may provide sixteen swing frequency bands for encoding
four binary data signals.
[0198] The discussion now turns to the demodulation scheme and the
demodulation device used for decoding the feedback signals from the
Implant. FIG. 23A shows a frequency spectrum of the frequency
modulation feedback signal according to an embodiment of the
present invention. Generally, the frequency modulation feedback
signal may occupy one of the low state band 2202 or the high state
band 2204 to transmit a single binary bit of data. However, the
frequency modulation feedback signal may shift from a higher end of
the band to a lower end of the band as the regulation voltage
V.sub.REG of the implant increases. Such intra-band frequency shift
may occur during the transmission of the single binary bit of data.
Advantageously, the RF Board may be able to regulate the power
within the Implant in real time, so that the regulation process may
be independent of the data transmission process.
[0199] FIG. 23B shows a demodulation 2300 of the frequency
modulated amplitude modulation signal according to an embodiment of
the present invention. Generally, the demodulation signal may map a
low frequency band to a high voltage state, and it may map a high
frequency band to a low voltage state. Moreover, the demodulation
signal may have a first DC level 2310 when the implant requests no
regulation, and it may have a second DC level 2330 when the Implant
requests power reduction (or power regulation). Accordingly, a
potential difference 2320 between the first and second DC levels
2310 and 2320 may correspond to the level of power reduction
requested by the Implant.
[0200] FIG. 23B shows that the maximum regulation demodulation
signal may overlap with the no regulation demodulation signal.
However, in an alternative embodiment, the maximum regulation
demodulation signal and the no regulation demodulation signal may
occupy non-overlapping voltage ranges.
[0201] Referring to FIG. 24, a schematic view of a demodulation
device 2400 is shown according to an embodiment of the present
invention. Generally, the demodulation device 2400 may implement
the functional features of the demodulation device 1330 as
discussed in FIG. 13. Particularly, the demodulation device 2400
may include a demodulation processor 2410, a low pass filter 2420,
a signal strength amplifying stage 2422, a data amplifying stage
2432, a three-stage power control amplifying stage 2440, and a
power override device 2450.
[0202] The demodulation processor 2410 may be used for processing
the signal ANT_RX, which may be received and extracted from the
external antenna. The signal strength amplifying stage 2422 may
receive the processed signal and generate a signal strength
indicator signal RSSI. Generally, the signal strength indicator
signal RSSI may indicate the strength of the telemetric coupling
between the external antenna and the implant antenna.
[0203] The low pass filter 2420 may be used for filtering out the
high frequency component of the processed signal. As such, the
carrier frequency may be eliminated, and the frequency modulated
feedback signal may be further processed. Next, the data amplifying
stage 2432 may receive the filtered signal and generate a data
signal RF_RX according to the state band of the filtered signal.
Simultaneously, the three-stage power control amplifying stage 2440
may receive the filtered signal and generate a voltage supply
control signal VSUP_CTRL according to the frequency shift caused by
the regulation voltage VREG.
[0204] Accordingly, the power supply device 1340 (previously shown
in FIG. 13) may use the voltage supply control signal VSUP_CTRL to
adjust the RF supply voltage 1342. Because the modulation device
1320 may be powered by the RF supply voltage 1342, the amplitude
component of the amplitude modulation signal may be controlled
indirectly by the RF supply voltage 1342. As a result, the power
transmission may be regulated by reducing the amplitude component
of the amplitude modulation signal.
[0205] Additionally, the three-stage power control amplifying stage
may include a second stage 2444 for generating a regulation level
signal REG_LEVEL, which may indicate the level of regulation
requested by the Implant. Generally, the level of regulation may be
higher when the Implant's DC input voltage VIN is much higher than
the breakdown voltage VBD. Alternatively, the level of regulation
may be lower when the Implant's DC input voltage VIN is below or
slightly above the breakdown voltage VBD.
[0206] FIG. 25 shows the relationship among various output signals
of the demodulation device and a transmission distance separating
the external antenna and the implant antenna. Generally, as the
transmission distance increases, the signal strength indicator
signal RSSI and the regulation level signal REG_LEVEL may increase.
As such, the RF voltage supply VSUP may decrease to reduce the
power transmission to the Implant. As shown in FIG. 25, the RF
Board and the Implant may undergo rapid power regulation when the
transmission distance ranges from 30 mm to about 40 mm. Moreover,
the RF Board and the Implant may undergo maximum power regulation
when the transmission distance is below 20 mm.
[0207] According to an embodiment of the present invention and
referring again to FIG. 11, the FM demodulator in the RF
demodulator block 1108 may generate a received signal strength
indicator (RSSI), a REG_LEVEL signal and a VSUP_CTRL signal.
Ultimately the VSUP_CTRL signal controls the output voltage VSUP.
FIG. 25 shows some examplary results of the RSSI signal, the
REG_LEVEL signal, and the output voltage VSUP at various
transmission distances.
[0208] The discussion now turns to the software algorithms
implemented in the HID subsystem and the RF subsystem. FIG. 26
shows the communication protocol UART 2600 among the HID subsystem,
RF subsystem, and the implant according to an embodiment of the
present invention. Generally, the HID microcontroller 2622 may
function as the master device within the control device (control
unit) 2620 and it may control most user interfaces, such as the
display device, the buttons, the audio output device (e.g.,
speaker), and the memory devices. The HID microcontroller 2622 may
send command message 2602 to the RF microcontroller 2624, and
request the RF microcontroller 2624 to perform several
functions.
[0209] The RF microcontroller 2624 may perform as a slave to the
HID microcontroller 2622. Nevertheless, the RF microcontroller 2624
may send notification messages 2604 to the HID microcontroller 2622
even without being requested. The RF microcontroller 2626 may
control the power induction process in the implant, the charging
circuit in the docking station, the communication to and from the
implant, and the communication with the HID microcontroller 2622.
The GND-GND link 2608 may provide the "0 Volt" reference for all
other signals. The RTS-CTS link 2606 may be a flux control line,
which may be used for stopping the incoming flux of data from the
HID sub-system when the RF sub-system is not ready to accept
them.
[0210] FIG. 27 shows the state diagram of the HID subsystem
algorithm 2700 according to an embodiment of the present invention.
Each state and transition will be discussed in detail in
conjunction with FIGS. 8A-8R, which shows various screen shots of
the control device. Generally, there may be five major blocks of
states, including the power off block 2710, the active or power on
block 2720, the charge block 2750, the error block 2760, and the
warning block 2770.
[0211] The transition from the power off block 2710 to the power on
block 2720 may be triggered by pressing the power on button on the
control device 110 as shown in FIGS. 5A and 5B. Similarly, the
transition from the power on block 2720 to the power off block 2710
may be triggered by pressing the power off button or after a
10-minute time out delay since a user has not interacted with the
HID subsystem.
[0212] Generally, any state within the power on block 2720 may
transit to the warning block 2770 and/or the error block 2760. To
exit the warning block 2770 and/or the error block 2760, the user
may enter the power off block 2710 by pressing the power off button
or waiting for the 10-minute time out delay.
[0213] The charge block 2750 may be entered when the control device
is connected to the docking station during the active mode. Once
the control device is disconnected from the docking station, the
charge block 2750 may return to a previous state of the power on
block 2720. Normally, the returned state may be a state from which
the charge block 2750 is transited initially.
[0214] As the power on block 2720 is initiated, the INIT state 2722
may initialize the HID subsystem, display the welcome screen, and
load the code entry screen. After that, the ASKING FOR CODE state
2724 may be entered. The ASKING FOR CODE state 2724 may repeat
itself until a correct 4-digit pass code is received, upon which
the SEARCHING state 2726 may be entered. Once the external antenna
is positioned close enough to the implant to establish a sufficient
good telemetric (or electromagnetic) coupling, which may be
represented by three out of five search bars in the searching
screen, the UPLOADING state 2728 may be initiated.
[0215] In the UPLOADING state 2728, the loading start screen may be
displayed, followed by the loading end screen. Moreover, the
implant is powered up and the communication with the implant is
initiated. If, at any point of the UPLOADING state 2728, the
telemetric coupling deteriorates and becomes insufficient, the HID
subsystem may return to the SEARCHING state 2726. Otherwise, the
patient information is uploaded from the implant such that the
STANDBY state 2730 may be initiated.
[0216] The STANDBY state 2730 may lead to several states depending
on the triggering conditions. For example, if the magnetic coupling
deteriorates and becomes insufficient, the HID subsystem may return
to the SEARCHING state 2726. For another example, if the Locked key
is pressed, the HID subsystem may enter the LOCKED state 2732 in
which the locked screen may be displayed, and from which any key
may be pressed to return to the ASKING FOR CODE state 2724.
[0217] For yet another example, if the code-change auxiliary key is
pressed, the HID subsystem may enter the ASKING FOR OLD CODE state
2734 in which the enter-old-code screen may be displayed. Once the
correct 4-digit code is received and the Next auxiliary key is
pressed, the ASKING FOR NEW CODE state 2736 may be entered, in
which the enter-new-code screen may be displayed. After receiving
the new 4-digit code, the HID subsystem may enter the CONFIRM NEW
CODE state 2738, in which the confirm-or-cancel-code screen may be
displayed and the user may elect to either confirm or cancel the
entered code. If the user presses the OK auxiliary key to confirm
the entered code, the code changed screen may be displayed and the
HID subsystem may return to the STANDBY state 2730; otherwise, if
the user presses the Cancel auxiliary key to cancel the entered new
code, the HID subsystem may simply return to the STANDBY state
2730.
[0218] While in the STANDBY state 2730, the user may request a
graph of the patient's gastric band adjustment history by pressing
the Chart auxiliary key. Accordingly, the GRAPH state 2740 may be
entered, and the history plot screen may be displayed. From the
GRAPH state 2740, the HID subsystem may enter the LIST state 2742
if the user presses the List auxiliary key, thereby loading the
history list screen. After reviewing the history plot screen and/or
the history list screen, the user may press the Return key to
return to the STANDBY state 2730.
[0219] Moreover, the user may adjust the width of the gastric band
from the STANDBY state 2730. For example, when the Open button is
pressed, the HID subsystem may enter the MOVE IMPLANT state 2744,
in which the opening screen may be displayed. Accordingly, the
implant motor may drive the gastric band to expand its diameter.
For another example, when the Close button is pressed, the HID
subsystem may initiate the MOVE IMPLANT state 2744, in which the
closing screen may be displayed. Accordingly, the implant motor may
drive the gastric band to constrict its diameter.
[0220] In order to achieve a desirable gastric band diameter, the
user may repeat the above process either by pressing the Open
button or Close button repeatedly, or by pressing the Open button
and the Close button alternately. During the MOVE IMPLANT state
2744, if the implant motor is blocked and such blockage is
detected, the HID subsystem may return to the STANDBY state 2730.
Moreover, during the MOVE IMPLANT state 2744, if the magnetic
coupling deteriorates and becomes insufficient, the HID subsystem
may return to the SEARCHING state 2726.
[0221] When the control device is connected to the docking station,
the CHARGE block 2750 may be entered, during which the battery
recharging may be performed and the battery recharging screen may
be displayed. In the CHARGE block 2750, the initial state is the
FAST CHARGE state 2752, during which the recharging process is
controlled by current. Once the fast charging is complete, the
NORMAL CHARGE state 2754 may be entered, and the battery recharging
process may be controlled by voltage. Once the battery is fully
charged, the HID subsystem may enter the FULL CHARGE state 2756.
The HID subsystem may alternate between the NORMAL CHARGE state
2754 and the FULL CHARGE state 2756 if the control device remained
connected to the docking station long enough for the battery to
dissipate some of the charges.
[0222] The discussion now turns to the RF subsystem algorithm. FIG.
28 shows the state diagram of an RF subsystem algorithm 2800
according to an embodiment of the present invention. The RF
subsystem powers and communicates with the implant, such that it
may manage the implant's telemetric (electromagnetic) coupling,
control the implant's power consumption, count the motor steps, and
receive feedback information from the implant. The RF subsystem may
also communicate with the HID subsystem, monitor battery
recharging, respond errors and interrupts, and perform cyclic
redundant check (CRC), delay, filtering and driving.
[0223] As shown in FIG. 28, the RF module cycles among four
different states, each of them may last about 500 .mu.s. The first
state may be the HID Communication state 2810, in which the RF
subsystem may receive up to two commands from the HID subsystem. In
response, the RF subsystem may respond to these commands by sending
up to eight notification messages. The second state may be the RF
Power state 2820, in which the power level to the implant may be
monitored and controlled. The third state may be the Implant
Communication state 2830, in which data may be sent to and/or
received from the implant. The received data may be further
analyzed in this state. The fourth state may be the Battery Charger
state 2840, in which battery power may be monitored and controlled
if the control device (control device) is properly connected to the
docking station. Generally, the RF subsystem may cycle or return
back to the HID Communication state 2810 after completing the
Battery Charger state 2840.
[0224] Referring again to FIG. 26, the HID microcontroller 2622 may
interact with the RF microcontroller 2624 through a UART interface
2600. Generally, the HID microcontroller 2622 (master) may send up
to two commands consecutively. The HID microcontroller 2622
(master) may demand answer messages from the RF microcontroller
2624 (slave). In response, the slave may send up to eight
notifications consecutively to the master. According to an
embodiment of the present invention, Table 2 below shows the data
structures for the command, the answer message and the notification
message.
TABLE-US-00002 TABLE 2 Data structures of the command message, the
answer message, and the notification message. HEADER DATA CRC CODE
SEQ LENGTH DATA[0] . . . DATA[Length-1] CRC COMMAND FROM MASTER
(HID) 16-bit 16-bit 16-bit 16-bit . . . 16-bit 16-bit ANSWER
MESSAGE FROM SLAVE (RF) 0x0000 16-bit 16-bit 16-bit . . . 16-bit
16-bit NOTIFICATION MESSAGE FROM SLAVE (RF) 0x4154 16-bit 16-bit
16-bit . . . 16-bit 16-bit
[0225] These command and messages may share a similar data
structure, which may includes a six-byte header followed by a
2*LENGTH-byte long data field and a two-byte CRC code. As discussed
herein, LENGTH may be a predefined parameter specifying the length
of the data. Within the six-byte header, the first two bytes
contain the command code, the next two bytes contain a sequence
number, and the last two bytes describe the LENGTH of the following
data field. The data field may be empty if LENGTH equals 0.
[0226] Generally, the HID master does not transmit all the header
bytes at one time. In one embodiment, for example, FIG. 29A shows a
command only communication protocol between the HID and RF
subsystems. More particularly, the HID master may send a two-byte
command code to the RF slave, which may respond by sending back an
ACK message. Upon receiving the ACK message, the HID master may
begin transmitting the Sequence bytes, the LENGTH bytes, and the
CRC bytes according to the shown order.
[0227] In another embodiment, for example, FIG. 29B shows a
command-data communication protocol between the HID and RF
subsystems. The protocol illustrated in FIG. 29B may be similar to
the protocol illustrated in FIG. 29A except that the Data bytes may
be sent after the LENGTH bytes.
[0228] Next, FIG. 30 shows an answer message communication protocol
from the RF subsystem according to an embodiment of the present
invention. After receiving and processing the command message from
the HID master, the RF slave may send back an answer message with
data structure as shown in Table 2. Similarly, FIG. 31 shows that
the RF slave may initiate notification message without receiving
prior command from the HID master.
[0229] The discussion now turns to the features of the docking
station. FIGS. 32A-32C show an exploded view, a front view and a
back view of a docking station 3200 according to an embodiment of
the present invention. Generally, the docking station 3200 may
include a bottom shell 3202, a top shell 3204, four rubber foot
3206, a regulatory sticker 3208, a ballast 2 bottom 3210, a ballast
1 top 3212, a magnet 3214, two alignment pins 3216, a main PCB
3218, and a supplementary PCB 3220.
[0230] The docking station 3200 may have a saddle structure 3232,
which may provide one or more contact point for coupling with the
control device. The main PCB 3218 may be used for performing power
protection to protect the docking station 3200 and the control
device from the power surge of the power adapter. Moreover, the
main PCB 3218 may assist the RF subsystem in monitoring the
charging status and the charging temperature.
[0231] FIG. 33 shows a schematic view of the docking station
subsystem 3310 interacting with the RF Board 3350 according to an
embodiment of the present invention. The docking station system
3310 may be implemented by the main PCB 3218 (see FIG. 32), and it
may include a temperature measurement block 3312, a power supply
management block 3314, a protection block 3316, and a shunt
resistance device 3318. The power supply management block 3314 may
interact with the RF board 3350 to perform battery charging
(charging status) management and charging temperature (overheat
prevention) management.
[0232] Charging current may be estimated by measuring voltage
across the shunt resistance device 3318. In one embodiment, for
example, the shunt resistance device 3318 may have a resistance of
about 0.015.OMEGA.. Moreover, there may be NTC thermistors inside
the batteries for proper temperature measurement, as well as
several polyswitches for resetting the circuit in case of power
surges at the battery level.
[0233] FIG. 34 shows a fast charge mode voltage-current chart
according to an embodiment of the present invention. At the
beginning of the fast charge mode, the charging process is
controlled through a constant current I.sub.ch. According to an
embodiment of the current invention, I.sub.ch may be about 5 A.
After the battery charge V.sub.B reaches a certain voltage, it will
decrease by .DELTA.V and the charging circuit then switches to the
normal charge mode.
[0234] The RF board may perform the charge monitoring. A dedicated
NiMh charger chip (e.g., the LTC1759 chip) may be used for
controlling the charging process. The LTC1759 chip may use
temperature measurement of the battery pack to adjust its charging
algorithm. The LTC1759 chip may be a high current DC-to-DC power
supply controlled by a NiMH charger controller, both of which may
be included in a single chip. Thus, the LTC1759 chip may control
the power given to the battery pack and ensure that it complies
with the charging profile as shown in FIG. 34.
[0235] The discussion now turns to the retractable external antenna
(external antenna with retractable cable). FIGS. 35A-35B show a
perspective view and an exploded view of an external antenna with
retractable cable according to an embodiment of the present
invention. Generally, the retractable external antenna 3500 may
include an antenna bottom 3502, an antenna top 3504, a winding drum
3506, a gear wheel 3508, a button 3510, a button ring 3512, a metal
plate 3514, a PCB 3516, a tap 3518, a compression spring 3522, a
drive spring 3524, an antenna cable 3526, a gear wheel pin 3528, a
center axis 3530, a winding drum lid 3532, a sound barrier 3534, a
glide plate 3536, and a ball bearing 3538.
[0236] To achieve smooth retraction, the retractor components are
placed inside of the winding drum 3506 while the antenna cable 3526
retracts on the circumferential surface of the winding drum 3506.
In order to enable proper power induction, the cable of the antenna
may be fully deployed until a green marker can be seen. Otherwise,
the coiled antenna cable may absorb excessive power induction
energy. The retractable external antenna can be attached to the
control device by pushing the connector against the control device
until a "click" is heard, which signifies that the antenna cable
3626 is locked. Once locked, the antenna cable 3626 is in a
suitable configuration. The locking mechanism ensures a good
electromagnetic coupling by establishing a unique and stable
resting position for the cable.
[0237] The gear wheel 3508 may include a small spring loaded pin
(gear wheel pin) 3528. The antenna top 3504 may have a small hole
(not shown). The "click" sound may be produced when the spring
loaded pin 3528 enters into the small hole. This may occur when the
spring loaded pin 3528 is in front of the hole after the antenna
cable 3526 is fully unwound. When the bottom ring 3512 is pressed,
the spring loaded pin 3528 may be disengaged, thereby releasing the
antenna cable 3526.
[0238] As shown in FIGS. 36A and 36B, the retractable external
antenna 3500 may be stored at the back of the control device
according to an embodiment of the present invention. The magnetic
pins 3606 of the control device provide easy connection points for
connecting to the docking station.
[0239] The discussion now turns to various structural and
functional features of the implant. Referring to FIGS. 37A-37B, a
perspective view and an exploded view of the implant 3700 (e.g., a
gastric band system) are shown according to an embodiment of the
present invention. Generally, the implant 3700 may include a
membrane shell 3702, a dorsal element 3704, a motor sleeve 3706, an
implant electronic device enclosure (protection case) base and
cable sleeve 3708, a manipulation handle 3710, a cable sleeve 3712,
a skeleton 3714, an implant electronic device enclosure (protection
case) cover 3716, a motor and cable assembly 3718, a flexible screw
assembly 3720, an implant electronic device PCB 3722, and a
stabilizing tube 3724.
[0240] The dorsal element 3704 may have a first end, a second end,
and a curvy semi-tubular body connecting the first and second ends.
The first end of the dorsal element 3704 may have a flange lock and
a first opening, while the second end of the dorsal element 3704
may have an open compartment.
[0241] Similarly, the skeleton 3714 may have a distal end, a
proximal end, and a ladder body connecting the distal end and the
proximal end. The proximal end of the skeleton 3714 may have an
open compartment for receiving the motor assembly 3718. Initially,
the distal end of the skeleton 3714 may slide into the second end
of the dorsal element 3704, along its semi-tubular body, and stop
at the first end of the dorsal element 3704. The distal end of the
skeleton 3714 may be secured to the first end of the dorsal element
3704, while the open compartment of the skeleton 3714 may fit into
the open compartment of the dorsal element 3704. In such manner,
the ladder body of the skeleton 3714 may push against the inner
surface of the semi-tubular body of the dorsal element 3704.
Accordingly, the skeleton 3714 may provide support to the
semi-tubular body of the dorsal element.
[0242] The stabilizing tube 3724 may be inserted into the ladder
body of the skeleton 3714, such that it may be used for filling in
the space defined by the ladder body and for stabilizing the ladder
structure.
[0243] The motor assembly 3718 may have a motor coupled to a motor
cable. The motor may be arranged to receive and maneuver the
flexible screw assembly 3720. For example, the motor may have one
or more set of rotors and/or gears for engaging a threaded section
of the flexible screw assembly 3720. The motor may move a crimped
end of the flexible screw assembly 3720 towards or away from the
motor.
[0244] The flexible screw assembly 3720 may have a hooked end,
which may be guided through a center conduit (space) of the
stabilizing tube 3724. Because the stabilizing tube 3724 is adapted
to the curvy shape of the dorsal element 3704, the flexible screw
assembly 3720 may be bended with the stabilizing tube 3724. After
leaving the stabilizing tube 3724, the hook end of the flexible
screw assembly 3720 may be secured to the distal end of the
skeleton, which may be secured to the first end of the dorsal
element.
[0245] Next, the motor of the motor assembly 3718 may engage the
flexible screw assembly 3720. The flexible screw assembly may have
an inner section that is inserted into the stabilizing tube 3724.
Also, the flexible screw assembly 3720 may have an outer section
that stays outside of the stabilizing tube 3724 and extends beyond
the open compartments of the skeleton 3714 and of the dorsal
element 3704. The motor of the motor assembly 3718 may then engage
the threaded section of the flexible screw assembly 3720, and move
the crimped end of the flexible screw assembly 3720 away from the
motor.
[0246] The membrane shell 3102 may have a tubular body, which may
be used for covering the semi-tubular body of the dorsal element
3704. The cable sleeve 3712 may be used for covering and protecting
the motor cable, and the motor sleeve 3706 may be used for covering
and protecting the motor.
[0247] The open end of the motor cable may be soldered onto the
implant electronic device PCB 3722, which may be protected by the
enclosure cover 3716 and the enclosure base 3708. The flange of the
manipulation handle 3710 may be inserted through the hole of the
implant electronic device enclosure, folded over, and secured to
the implant electronic device enclosure by applying an appropriate
amount of MED2-4213 silicon glue or the equivalent thereof on the
flange and the cavity of the manipulation handle 3710. The tapered
end of the manipulation handle may be inserted and guided through
the opening located at the first end of the dorsal element 3704,
thereby leading the second end of the dorsal element 3704 to be
inserted into the first end of the dorsal element 3704.
[0248] Consequently, the dorsal element 3704, and the membrane
shell 3702, may form a ring structure. Particularly, the ring
structure may have an adjustable ventral (inner) ring surface and a
rigid dorsal (outer) ring surface. The adjustable ventral ring
surface may be equipped with several cushion members for applying
pressure against the stomach of a patient.
[0249] As persons skilled in the art may readily appreciate, an
appropriate amount of MED2-4213 silicon glue, or the equivalence
thereof, may be applied to various components, and the various
junctions of thereof, of the implant 3700 for strengthening the
overall structure of the implant 3700.
[0250] The discussion now turns to the implant electronic device
protection case (enclosure) components. Generally, the implant
electronic device PCB 3722 may be coupled to the motor cable, such
that the implant electronic device PCB 3722 may send control
signals to the motor and sense a motor coil current of the motor.
The implant electronic device PCB 3722, and the junction at which
the implant electronic device is coupled to the motor cable, may be
protected by the implant electronic device enclosure, which may
include the enclosure cover 3716, the enclosure base 3708, and the
strain relieving sheath 3850.
[0251] FIGS. 38A and 38B shows a top perspective view and a bottom
perspective view of an enclosure base shell 3810 according to an
embodiment of the present invention. Generally, the enclosure base
shell 3810 may be part of the enclosure base 3708. Particularly,
the enclosure base shell 3810 may include a compartment 3814 for
fitting the electronic device PCB 3722, a cable port 3812 for
receiving and guiding the motor cable, and a handle hinge 3816 for
receiving the flange of the manipulation handle 3710.
[0252] Referring to FIG. 38C, a perspective view of a cladding 3820
is shown according to an embodiment of the present invention.
Generally, the cladding 3820 may be part of the enclosure cover
3716. Particularly, the cladding 3820 may be coupled to and
cooperate with the enclosure base shell 3810 for guiding and
protecting the motor cable. The cladding 3820 may include a
plurality of openings to allow silicon material to be overmolded
therein.
[0253] Referring to FIG. 38D, a perspective view of an enclosure
cover shell 3830 is shown according to an embodiment of the present
invention. Generally, the enclosure cover shell 3830 may be part of
the enclosure cover 3716. The enclosure cover shell 3830 may be
detachably coupled to the enclosure base shell 3810 and the
cladding 3820 to form the enclosure case. The enclosure case may
provide stability and protection for the implant electronic device
PCB 3722 and for the connection established between the implant
electronic device PCB 3722 and the motor cable.
[0254] Referring to FIG. 38E, the strain relieving sheath 3850 may
be used for providing flexible support for the motor cable around
the cable port 3812 area. The strain relieving sheath 3850 may help
prevent breakage of the motor cable by restraining the motion of
the motor cable around the cable port 3812 area. Referring to FIG.
38F, the extremity of the strain relieving sheath 3850 may have a
silicone-PEEK overmolding and a plurality of internal bumps 3852
for keeping the cladding 3820 centered and for distributing the
glue evenly.
[0255] The discussion now turns to the implant electronic device
PCB 3722. FIGS. 39A-39B show a top view and a bottom view of an
implant electronic system board (PCB) 3900, which may be used for
implementing the functional features of the implant electronic
device PCB 3722. Referring to FIG. 39A, the PCB 3900 may include a
power regulation subsystem circuitry 3901, a microprocessor 3902,
and an implant antenna 3904. The implant (internal) antenna 3904
may loop around the periphery of the PCB 3900, and it may be
responsible for receiving the RF signals transmitted from the
external antenna of the control device.
[0256] The power regulation subsystem circuitry 3904 may be coupled
to the implant antenna 3904 via the L2 connection port 3906. The
power regulation subsystem circuitry 3901 may include a power
regulator 3908 for maintaining the local voltage V.sub.cc.
Moreover, the power regulation subsystem circuitry 3904 may receive
the induced power and generate the power regulation signals when
the DC input voltage V.sub.IN is above certain predetermined
threshold (e.g. 5.6 V).
[0257] The microprocessor 3902 may be coupled to the power
regulation subsystem circuitry 3901. The microprocessor 3902 may be
coupled with the implant antenna 3904. Generally, the
microprocessor 3902 may be used for generating frequency modulation
signals, which may be embedded with power regulation information
and gastric band adjustment history information.
[0258] Particularly, the microprocessor 3902 may be used for
receiving and processing commands send from the control device 110
as shown in FIG. 1. For example, the microprocessor 3902 may
receive a gastric band adjustment command from the control device
110. In response, the microprocessor 3902 may send motor step
signal to the motor for adjusting the width of the gastric
band.
[0259] Moreover, the microprocessor 3902 may receive a gastric band
adjustment history request command from the control device 110. In,
response, the microprocessor 3902 may retrieve the requested data
from a memory device (not shown) and send the retrieved data back
to the control device. In one embodiment, the microprocessor 3902
may have about 8 kB of programmable memory, 512 Bytes of data
memory, 512 Bytes of SRAM, two timers, several input and out pins,
one comparator, an A/D converter and several interrupt sources.
[0260] Referring to FIG. 39B, the bottom surface of the implant
electronic system board 3900 may have nine oval connection pads
3912, each of which may be soldered to one of nine motor wires of
the motor cable. Among the nine ovals connection pads 3912, eight
of them may be grouped in four parallel pairs to provide redundancy
protection. The remaining one oval connection pad 3912 may be
soldered to an FC wire. The large metallic surface 3914 may be
soldered to a motor cable center ground wire (GND).
[0261] The discussion now turns to the structural and functional
features of the manipulation handle 3710. FIGS. 40A-40C show
various views of a manipulation hand 4000, which may be used for
implementing the functional features of the manipulation handle
3710. Generally, the manipulation hand 4000 may have a tapered end
4042, a base end 4044, an elongated body 4043 connecting the
tapered end 4042 and the base end 4044, and a flange 4052 coupled
to the base end 4044.
[0262] The flange 4052 may engage the handle hinge 3816 of the
implant electronic device enclosure 3810. The profiled of the
elongated body 4043 may allow easier insertion into the opening of
the dorsal element. Specifically, the elongated body 4043 may have
an increase thickness from the tapered end 4042 to the base end
4044. Moreover, the elongated body 4043 may have helicoidal arrows
4046, which may be used for indicating the direction for insertion.
In one embodiment, the helicoidal arrows 4046 may form on one side
of the elongated body 4043. In another embodiment, the helicoidal
arrows 4046 may form on both sides of the elongated body 4043 as
shown in FIG. 40C. Accordingly, the helicoidal arrows 4046 may be
viewed at most angles during the implant procedure.
[0263] Referring to FIG. 40B, the manipulation handle 4000 may have
first, second, third and fourth widths. In one embodiment, for
example, the first width 4002 may be about 10.34 mm, the second
width 4004 may be about 17 mm, the third width 4006 may be about
3.33 mm, and the fourth width 4008 may be about 4.2 mm.
[0264] Referring to FIG. 40C, the manipulation handle 4000 may have
a flange length 4010 and a body length 4038. In one embodiment, for
example, the flange length 4010 may be about 13.5 mm, and the body
length 4038 may be about 100.3 mm. The flange 4052 may have a
flange thickness 4012, which may be about 1.4 mm. The elongated
body 4043 may have twelve thicknesses. In one embodiment, for
example, the first thickness 4014 may be about 4.96 mm, the second
thickness 4016 may be about 4.5 mm, the third thickness 4018 may be
about 3.9 mm, the fourth thickness 4020 may be about 3.6 mm, the
fifth thickness 4022 may be about 3.45 mm, the sixth thickness 4024
may be about 3.42 mm, the seven thickness 4026 may be about 3.4 mm,
the eighth thickness 4028 may be about 3.2 mm, the ninth thickness
4030 may be about 3.03 mm, the tenth thickness 4032 may be about
2.9 mm, the eleventh thickness 4034 may be about 2.8 mm, and the
twelfth thickness 4036 may be about 1.7 mm.
[0265] The discussion now turns to the software algorithm of the
implant electronic system. In FIG. 41, a state diagram of implant
electronic device software algorithm is shown according to an
embodiment of the present invention. Generally, the implant
electronic device software algorithm may be executed by the
microprocessor 3902 to perform various functions, such as driving
the motor, counting the motor steps, detecting and eliminating
motor blockage, storing and sending the patient's identification
number and record information, such as the implantation date and
the history of the last ten adjustments, and performing a self test
on motor coils and other electronic components.
[0266] Upon receiving inductive power from the RF Board, the
implant electronic system may enter the "Init" state 4100, in which
the microprocessors, the A/D converters, the input/output devices,
interrupt devices, comparator, and watchdog devices may be
initialized. Once the initialization is completed, the implant
electronic system may enter the "Power On Self Test" state 4102, in
which the motor coils may be tested. If the self test is
successful, the implant electronic system may enter the "Send ID"
state 4108. Otherwise, the implant electronic system may enter the
"Error Detected" state 4104, in which the RF transponder may notify
the control device 110 with the appropriate message.
[0267] The "Send ID" state 4102 may be the default state, such that
it may loop itself and continuously send ID messages back to the
control device 110 until additional command is sent form the
control device.
[0268] Referring to FIGS. 42A and 42B, the data structure of the ID
messages may include three ID bytes, two status bytes, three motor
position bytes, and one CRC code check byte.
[0269] Referring again to FIG. 41, the implant electronic system
may transit out of the "Send ID" state 4102 once it receives a
command from the control device. For example, the implantation date
will be recorded in the EEPROM in the "Record Date" state 4112 if a
"record date" command is received and the implantation flag is
False. For another example, the last 10 implant's positions will be
sent back to the control device during the "Send History" state
4116 if a "send history" command is received.
[0270] Moreover, the implant electronic system may enter the
"Adjust Band" state 4110 if an "Open" or "Close" command is
received. During the "Adjust Band" state, the motor sequence may be
activated, such that the motor may be directed to rotate clockwise
or counter-clockwise.
[0271] A complete list of commands and the associating transmission
protocol can be found on FIGS. 43B and 44B. Particularly, FIG. 43B
illustrates the data structure of commands that do not require
additional parameters being sent to the implant, whereas FIG. 44B
illustrates the data structure of commands that require additional
parameter.
[0272] Among the no-parameter commands, the
"ImplantRequestStopPower" command may instruct the implant to stop
powering the motor; the "ImplantRequestSelfTest" command may
request the implant to perform a self test procedure; the
"ImplantGetCurrentDate" command may request the implant to get the
current date; the "ImplantGetSerialNumber" may instruct the implant
to get the serial number; the "ImplantGetFirmwareVersion" may
instruct the implant to get the firmware version; the
"ImplantGetStepCounter" command may instruct the implant to gets
the current motor step counter; the "ImplantEepromRecovery" command
may instruct the implant to recover all stored EEPROM memory; and
the "ImplantGetExtendedStatusRegister" command may instruct the
implant to get value of an extended status register.
[0273] Among the with-parameter commands, the "ImplantOpenNStep"
command may ask the implant to turn the stepper motor clockwise by
a number of steps in order to open the band; the
"ImplantCloseNStep" command may ask the implant to turn the stepper
motor counter-clockwise by N number of steps in order to close the
band; the "ImplantWriteByteEeprom" command may instruct the implant
to write a byte of data into the EEPROM; the
"ImplantSetCurrentDate" command may instruct the implant to set and
store the current date; the "ImplantReadHistory" command may
instruct the implant to read the adjustment history; the
"ImplantGetParameters" command may instruct the implant to get some
specific parameters; and the "ImplantReadEepromRecovery" may
instruct the implant to recover a specific record stored in
EEPROM.
[0274] Referring again to FIG. 41, motor coil currents may be
monitored during the motor sequence initialization and throughout
the motor rotation phase for detecting and eliminating motor
blockage. If a motor blockage is detected, the implant electronic
system may enter the "Unblock Motor" state 4106 to resolve the
motor blockage issue. In one embodiment, the motor may be directed
to reduce its rotation speed, so that it may generate more torque
to overcome the motor blockage. In another embodiment, the motor
may be directed to change the rotation direction if the motor speed
reduction scheme fails to remove the motor blockage.
[0275] If these two schemes do not resolve the motor blockage
issue, the implant electronic system may enter the "Error Detected"
state 4104, in which an error message will be sent to the control
device 110.
[0276] Otherwise, the implant electronic system may return to the
"Adjust Band" state 4110 to continue adjusting the gastric band.
When the adjustment is completed, the implant electronic system may
enter the "Record Implant Position" state 4118, in which the last
adjustment and the received date will be recorded in the
EEPROM.
[0277] The discussion now turns to the communication protocol
between the control device and the implant electronic system. FIG.
49 shows a timing diagram of a computer interrupt sequence upon a
detection of a control device command at the implant. The command
4904 may be sent by the control device, and it may be carried by an
amplitude modulation signal at a carrier frequency of about 27 MHz.
Once the command 4904 is separated from the carrier, it may be fed
to a comparator to generate the interrupt sequence 4902. Referring
to the digital sequence 4906, the interrupts may be used for
starting and/or stopping a timer. For example, a low state values
(bit 0) and a high state values (bit 1) may be characterized as a
short period and a long period, respectively.
[0278] Referring to FIG. 43A, the implant may acknowledge the
reception of a command by responding with an ACK message if the
command does not contain any parameter. Referring to the FIG. 44A,
the control device may send a command with parameters. In one
embodiment, the parameters and the Cyclic Redundant Check (CRC)
code may be sent at about 2 ms intervals. If the CRC code
verification is successful, the implant may then respond with an
ACK message, which may confirm that the command is properly
received. Otherwise, the implant may send a NACK message to prompt
the control device to resend the command. As shown in FIGS. 45A and
45B, the data structures of the ACK message and the NACK message
may be similar except for the last four bits.
[0279] Referring to FIG. 46A, several commands may request
information from the implant. In response, the implant may embed
the requested information in a response message. Upon receiving the
response message and the embedded information, the control device
may respond with an ACK message.
[0280] In FIG. 46B, a data structure of a response message is shown
according to an embodiment of the present invention. Generally, the
response message may include a start bit, two synchronization bits,
eight "length" bits, several response message bits the size of
which is defined by the value contains in the "length" bits, and
eight CRC bits.
[0281] Referring to FIGS. 47A and 47B, several timeout conditions
may be met when the implant takes more than 200 ms to send back
either an ACK message or a response message. Generally, timeout
conditions and/or a NACK message from the implant may trigger the
resending of commands from the control device. According to an
embodiment of the present invention, this resending mechanism may
repeat up to about five times.
[0282] FIG. 50 shows a screen shot of the timing diagrams of the
control device's command and the implant's response. The response
time t.sub.resp may be measured from the sending of the command
5010 (from the control device 110) to the sending of the response
5020 (from the implant). The start pulse duration t.sub.sd may be
the duration for transmitting the first response pulse, and the
data bit duration t.sub.db may be the duration for transmitting one
message data bit. In one embodiment, the start pulse duration
t.sub.sd may be set at 400 .mu.s and the data bit duration t.sub.db
may be set at 200 .mu.s. In order to instruct the microcontroller
to stop its current task and get ready to receive the message, the
start bit duration may be set to low.
[0283] The discussion now turns to the gastric band adjustment
history storage function of the implant electronic system. In FIG.
48, a data structure of implant adjustment history record 4800
(hereafter "history data record") may be shown according to an
embodiment of the present invention. Generally, the history data
record 4800 may reserve four bytes for storing gastric band
position information, three bytes for storing date information, and
one byte for storing CRC code.
[0284] Particularly, the gastric band position may be represented
by about 71,000 motor steps, which may be stored in the four-byte
data field. Because the EEPROM in the CAD has a size of about 512
bytes, information may normally be stored in duplicates of 256-byte
size in a first record location and a second record location.
Advantageously, the implant electronic device may be able to use
the second set of records for data if the first set of records is
corrupted.
[0285] The motor used in the implant may be a step motor. One step
of the motor may correspond to one binary value stored in the
counter. The stored value of "0" may represent a substantially (or
fully) open band, while a stored value of "71,000" may represent a
substantially (or fully) closed band. Moreover, more than one
control devices may access and retrieve information from the
implant, such that multiple care-takers and/or physicians may
monitor and adjust the gastric band for the patient.
[0286] The discussion now turns to the operation of the motor.
Referring to FIGS. 55A-55B a perspective top view and a perspective
bottom view of a motor 5500 according to an embodiment of the
present invention. Generally, the motor 5500 may be used for
implementing the functional features of the motor assembly 3718 as
shown in FIG. 37B. The motor 5500 may include the upper bearings
5504, lower bearings 5508, a set of motor gears 5505, a first motor
coil 5506, a second motor coil 5507, a maneuver channel 5510, and a
motor switch PCB 5530.
[0287] The motor switch PCB 5530 may have a layer of gold plate
over the copper layer and large pads for cleaner thermo soldering,
and the set of motor gears 5505 may be covered by dry lubrication
with a diamond like coating (DLC) to achieve better surface tension
for avoiding water drop formation.
[0288] The maneuver channel 5510 may be used for receiving the
threaded section of the flexible screw. When the set of gears 5505
are turned, the flexible screw may be maneuvered along the maneuver
channel 5510. In a band widening step, for example, the flexible
screw may be maneuvered from the upper bearing 5504 side of the
maneuver channel 5510 to the lower bearing 5508 side of the
maneuver channel 5510. In a band tightening step, for example, the
flexible screw may be maneuvered from the lower bearing 5508 side
of the maneuver channel 5510 to the upper bearing 5504 side of the
maneuver channel 5510.
[0289] The motor 5500, the motor wires 5522, and the flexible screw
may be protected by several devices. Before entering the motor
5500, for example, the motor wires 5522 may be protected by the
motor cable 5524. At or near the lower bearings 5508, for example,
the motor wires 5522 may be protected by a cable cone 5542 of a
motor traveling PCB protection cap 5540.
[0290] Referring to FIGS. 55E-55F, a perspective bottom view and a
perspective top view of a motor traveling PCB protection cap 5540
are shown according to an embodiment of the present invention. The
motor traveling PCB protection cap 5540 may include the cable cone
and a PCB brace 5544. The cable cone 5542 may be used for
protecting the motor wires 5522. The PCB brace 5544 may be used for
protecting the lower bearings 5508 and holding the motor switch PCB
5530. The motor traveling PCB protection cap 5540 may be made of a
PEEK material, and it may be mounted to the lower bearing 5508 of
the motor 5500.
[0291] FIGS. 55C-55D show a perspective bottom view and a
perspective top view of motor cap 5520 according to an embodiment
of the present invention. The motor cap 5520 may cover the motor
traveling PCB protection cap 5540 and thereby providing further
protection for the lower bearing 5508 of the motor 5500. The motor
cap 5520 may define a maneuver aperture 5526, which may help guide
the longitudinal movement of the flexible screw 5560. The motor cap
5520 may include a set of flanges 5527, which may be used for
anchoring to the skeleton 5800. The motor 5500 may be partially
secured by the motor cap 5520 and the motor traveling PCB
protection cap 5540. After receiving and securing the motor 5500,
the motor cap 5520 may anchor the motor 5500 to the skeleton 5800.
The motor cap 5520 may have several rails to allow silicone to form
overmolding thereon.
[0292] The motor cable 5524 and part of the flexible screw may be
further protected by an overmold motor sleeve. Referring to FIGS.
55G-55H, a perspective side view and a perspective front view of a
motor sleeve 5550 are shown according to an embodiment of the
present invention. The motor sleeve 5550 may be made of an LSR
silicon material overmolded on a PEEK material. The LSR silicon
overmolded PEEK may provide a sealing surface to protect fluid from
entering the motor 5500. Moreover, the motor sleeve 5550 a
plurality of internal bumps 5552 to facilitate even gluing between
the interior of the motor sleeve 5550 and the motor cable 5524.
[0293] FIG. 55I shows an exploded view of a motor coil 5560
according to an embodiment of the present invention. Generally, the
motor coil 5560 may be used for implementing the first and/or
second motor coils 5506 and 5507. Particularly, the motor coil 5560
may include a first connection board 5564, a second connection
board 5566, a core 5562, an inner shield 5570, a coil body 5568,
and an outer shield 5572.
[0294] The first and second connection boards 5564 and 5566 may
provide a connection interface between the motor wires and the coil
body 5568. Moreover, the first and second connection boards 5564
and 5568 may help secure the coil body 5568 around the center of
the core 5562. The first and second connection boards 5564 and 5568
may engage the core 5562 and sandwich the coil body 5568 between
both ends of the core 5562. The coil body 5568 may have several
coils that are made of silver wire. When current passes through the
coils, the coil body 5568 may induce a magnetic flux along the core
5562. The inner and outer shield 5570 and 5572 may shield the coil
body 5568 from electromagnetic interference, such that the magnetic
flux generated by one motor coil (e.g., the motor coil 5506 or
5507) will not interfere with the magnetic flux generated by
another motor coil (e.g., the motor coil 5507 or 5506).
[0295] FIGS. 55J-55K show various views of the motor cable 5524
according to an embodiment of the present invention. Generally, the
motor cable 5524 may include a central conductor 5521, nine twisted
wires 5522, and a PTFE tape 5525. The central conductor 5521 may be
crimped and attached to the motor 5500 on one end, and it may be
crimped and soldered to the implant electronic system PCB 3722 on
the other end. The central conductor 5521 may be a ground wire or a
skeleton wire depending on the particular circuit configuration
being used.
[0296] Specifically, the central conductor 5521 may include
ninety-one MP35NLT alloy wires each with diameter of 0.04 mm. The
nine twisted wires 5522 may be connected to the first and second
motor coils or the end of a travel switch. Each of the nine twisted
wires 5522 may include seven AISI316L silver plated stainless steel
wires 5523, each of which may have a diameter of 0.12 mm.
[0297] FIG. 56 shows a side view of a flexible screw assembly 5600
according to an embodiment of the present invention. Generally, the
flexible screw assembly 5600 may be used for implementing the
functional features of the flexible screw assembly 3720. The
flexible screw assembly 5600 may have a hook end 5602, a central
wire 5604, an intercalary wire (threaded section) 5605, and a
crimped end 5608. The central wire 5604 may be surrounded by the
stabilizing tube as discussed in FIG. 37B, and it may be attached
to the end of the intercalary wire 5605 opposite to a crimped end
5608. Moreover, the central wire 5604 may be used for controlling
the size of the gastric band when the intercalary wire 5605 is
being moved back and forth the maneuver channel 5510 of the motor
5500 (see FIGS. 55A and 55B).
[0298] The flexible screw assembly 5600 may have an overall length
5612 of about 136.20 mm and with a tolerant range of about 0.1 mm.
The intercalary wire 5605 may have an overall length 5614 of about
52 mm and with a tolerant range of about 0.1 mm. The hook member
5602 may have a width 5601 and a length 5618. The width 5601 may be
about 2.5 mm and with a tolerant range of about 0.1 mm, whereas the
length 5618 may be about 8 mm and with a tolerant range of about
0.1 mm.
[0299] FIGS. 57A-57H provide various views of the motor 5500
engaging the flexible screw 5600 to illustrate the structural and
functional relationships between the motor 5500 and the flexible
screw assembly 5600. Initially, each of the first and second motor
coils 5506 and 5507 may receive a motor current from the implant
electronic device PCB 3722 and via the motor wires 5522. The first
and second motor coils 5506 may each generate a magnetic flux in
response to the received motor current. The generated magnetic flux
may be collected by the stator 5547, which may convert the magnetic
flux to mechanical force for driving a set of rotors 5541.
[0300] The set of rotors 5541 may be engaged to and for driving the
set of gears 5505. The set of gears 5505 may include a set of
auxiliary gears 5543 and a primary gear 5545. The set of auxiliary
gears 5543 may be engaged between the rotor 5541 and the primary
gear 5545, such that the set of auxiliary gears 5543 may redirect
the mechanical force from the rotor 5543 to the primary gear
5545.
[0301] The primary gear 5545 may be positioned within the maneuver
channel 5510. The upper bearings 5504 and the lower bearings 5508
may help position, stabilize, and secure the primary gear 5545
within the maneuver channel 5510. The primary gear 5545 may have an
internal threaded section for engaging the external thread of the
intercalary wire 5606 of the flexible screw 5600. When the primary
gear 5545 is set to rotate, it may move the intercalary wire 5606
along the maneuver channel 5510. As such, upon receiving the
mechanical force, the primary gear 5545 may actual a relative
longitudinal movement between the motor 5500 and the flexible screw
5600.
[0302] Because of the relative longitudinal movement actuated by
the primary gear 5545, the motor 5500 may slide along the
intercalary wire 5606. When the gastric band is formed, the hook
end 5602 of the flexible screw 5600 may be positioned in the
proximity of the motor 5500. As such, the size of the gastric band,
which can be defined in diameter and/or circumference, may be
adjusted by varying a relative distance between the hook end 5602
and an engagement position on the intercalary wire 5606. More
specifically, the engagement position is a position at which the
motor 5500 may engage the intercalary wire 5606. The size of the
gastric band may be increased by sliding the motor 5500 toward the
crimped end 5608 of the flexible screw 5600. Similarly, the size of
the gastric band may be reduced by sliding the motor 5500 toward
the hook end 5602 of the flexible screw 5600.
[0303] The discussion now turns to the motor and the motor blockage
detection mechanism. Referring to FIG. 51, a schematic view of a
motor coil current measurement system 5100 is shown according to an
embodiment of the present invention. The connection between the
motor and the implant electronic device may be established via ten
conductor cable wires. The cable wires 5122 and 5124 may be
connected to the screw end of a travel switch. In one embodiment,
the cable wire 5122 may be one of the motor wires 5522, and the
cable wire 5124 may be the center conductor 5521 as shown in FIG.
55K.
[0304] Generally, the eight cable wires connecting to the motor
coils may be duplicated and connected in parallel. In one
embodiment, for example, the cable wire 5102 may duplicate the
cable wire 5104, the cable wire 5106 may duplicate the cable wire
5108, the cable wire 5112 may duplicate the cable wire 5114, and
the cable wire 5116 may duplicate the cable wire 5118. Each of the
cable wires 5102, 5104, 5106, 5108, 5112, 5114, 5116, and 5118 may
be implemented by one of the nine motor wires 5522 as shown in FIG.
55K.
[0305] The cable wires 5102 and 5104 may be connected to a first
end of the motor coil 2, while the cable wires 5106 and 5108 may be
connected to a second end of the motor coil 2. Similarly, the cable
wires 5112 and 5114 may be connected to a first end of the motor
coil 1, while the cable wires 5116 and 5118 may be connected to a
second end of the motor coil 1.
[0306] As previously discussed, the control device may request the
patient's identification number and history data from the implant
electronic system before the gastric band adjustment process. In
response, the implant electronic system may retrieve and send back
the requested information. After receiving the requested
information, the control device may be ready for adjustment. At
this point, the user may elect to tighten or loosen the gastric
band.
[0307] When the electronic device receives band adjustment commands
from the control device, it may initiate a motor-on sequence which
may include a motor positioning phase, a motor startup phase, and a
motor drive phase. During the motor position phase, the motor is
moved to a known position prior to the actual rotation start. Table
3 may illustrate the motor positioning phase:
TABLE-US-00003 TABLE 3 Sequences during motor positioning.
Direction Duration [ms] Coil 1 Coil 2 Band Closing 5 NEG POS 60 NEG
NEG Band Opening 5 POS POS 60 POS NEG
[0308] A positive pulse POS and a negative pulse NEG may be used
for driving the motor coils. During a band closing sequence, for
example, the first motor coil may receive a negative pulse for 5 ms
and then another negative pulse for 60 ms, whereas the second motor
coil may receive a positive pulse for 5 ms and a negative pulse for
60 ms. Table 4 may provide four pulse pair steps for rotating the
motor:
TABLE-US-00004 TABLE 4 Sequences for motor rotation. Pulse Pair
Band Closing Band Opening Label Coil 1 Coil 2 Coil 1 Coil 2 PPL0
POS NEG NEG NEG PPL1 POS POS NEG POS PPL2 NEG POS POS POS PPL3 NEG
NEG POS NEG
[0309] The pulse pair (PP) combination parameters may be stored in
the implant electronic device's EEPROM. Generally, two pairs of
pulses may drive a full turn of the motor, thereby completing a
single motor step. Accordingly, two motor steps may be completed
after executing pulse pairs PPL0 to PPL3. The completion of each
motor step may be reported back to the control device for
monitoring purposes. During the motor startup phase, the duration
of the pulses may be gradually decreased from about 5.12 ms down to
about 2.6 ms with a delta of about 0.15 ms after each pulse.
[0310] During the motor drive phase, a motor blockage may be
detected. The motor drive phase may be used for refining a minimal
pulse duration, which may range from about 2.6 ms to about 1.2 ms.
The minimal pulse duration may allow the motor coils to turn
smoothly without any motor blockage.
[0311] Referring again to FIG. 51, the minimal pulse duration may
be refined by detecting the motor coil currents across the
resistors 5132 and/or 5134. The motor coil currents may be
amplified by an analog amplifier and then digitized by an
analog-to-digital converter (ADC). In one embodiment, the analog
amplifier may be configured to have an amplifying power of 32, and
the ADC may be configured to generate a 10-bit digital number for
representing the value of the motor coil current.
[0312] Generally, the resistance of the resistors 5132 and 5134 may
be much smaller than the resistance of the motor coils 5142 and
5144. In one embodiment, for example, the resistance of the motor
coil 5142 or 5144 may be 167 times of the resistance of the
resistor 5132 or 5134. In another embodiment, for example, the
resistance of the resistors 5132 and 5134 may each be about
3.6.OMEGA., whereas the resistance of the motor coils 5142 and 5144
may each be about 600.OMEGA.. As such, the voltage drop across the
resistors 5132 and 5134 may be minimal when compared to the voltage
drop across the motor coil resistors 5142 and 5144. Therefore, the
resistance of the resistors 5132 and 5134 may have little effect on
the overall current flowing of the first and second motor
coils.
[0313] Sources of motor blockage may include increased force
required to close the band as its materials get more compressed. As
the radius of the band reduces, it would also become more difficult
to pull on the flexible screw 5600 regardless of the presence of
other materials. Biological tissue also gets more compressed as
radius decreases, leading to more required force from the motor.
The motor may be rated at a pulling force of 20 N but with typical
pulling force of 27 N, such that it would get stalled as the
required force would be higher than the typical pulling force.
[0314] The trend of motor coil current may indicate motor blockage
or the lack thereof. As shown in FIG. 52, for example, a first
current profile 5206 may represent a motor coil current of an
unblocked motor, and a second current profile 5208 may represent a
motor coil current of a blocked motor. In general, the resistance
of a blocked motor may be higher than an unblocked motor. To
maintain a relatively constant voltage across the motor, the motor
coil current of a blocked motor (e.g., the second current profile
5208) may increase rapidly during an initial period 5201 of a motor
step but slowly during a middle period 5202 of the motor step.
[0315] On the other hand, the resistance of an unblocked motor is
typically lower than that of a blocked motor. As such, the motor
coil current of an unblocked motor (e.g., the first current profile
5206) may increase slowly during the initial period 5201 but
rapidly during the middle period 5202. Both motor coil currents
(e.g., the first and second current profiles 5206 and 5208) may
reach a maximum motor coil current 5209 at an ending period 5204 of
the motor step. However, during the middle period 5202, the
integral sum of the blocked motor coil current (e.g., the second
current profile 5208) may be much greater than the integral sum of
the unblocked motor coil current (e.g., the first current profile
5206). This phenomenon may be attributed by the early ramping of
the blocked motor coil current and the late ramping of the
unblocked motor coiled current.
[0316] Based on several measurements, the integral sum of the
blocked motor current during the middle period 5202 is typically
greater than the maximum motor coil current 5209. To the contrary,
the integral sum of the unblocked motor current during the middle
period 5202 is typically less than the maximum motor coil current
5209. As such, the integral sum of a particular motor coil current
during the middle period 5202 may be compared to the maximum motor
coil current 5209 in determining whether the motor is blocked.
[0317] According to an embodiment of the present invention and as
shown in FIG. 54, the implant electronic device (e.g., a processing
device) may execute a software algorithm for detecting motor
blockage. The software algorithm may take advantage of the
aforementioned principle, and it may be stored in a tangible
computer readable medium. In one embodiment, for example, the
tangible computer readable medium may include a flash memory in the
implant electronic device. In another embodiment, for example, the
tangible computer readable medium may include, but not limited to,
random access memory (RAM), flash memory, read-only memory (ROM),
EPROM, EEPROM, registers, hard disk, removable disk, CD-ROM, DVD,
Blu-ray disk, wireless channels, and various other media capable of
storing, containing or carrying instruction(s) and/or data. In yet
another embodiment, the motor coil current may be measured by the
implant electronic device, while the motor blockage detection
software algorithm may be stored in and executed by the control
unit.
[0318] In step 5302, an integral sum value (idt) may be calculated
by measuring the integral sum of motor coil current (Integral_idt)
and normalizing the measurement. In one embodiment, the measurement
may be performed during the PPL2 pulse pair, and the normalization
may be performed by multiplying the measured integral sum of motor
coil current (Integral_idt) by a predetermined parameter
(constant_idt).
[0319] In step 5304, the maximum current (crt) may be calculated by
measuring the maximum motor coil current (Current_Max) and
normalizing the measurement. In one embodiment, the measurement may
be performed during the PPL3 pulse pair, and the normalization may
be performed by multiplying the measured maximum motor coil current
(Current_Max) by a predetermined parameter (constant_Max).
[0320] In step 5308, a determination can be made regarding whether
the integral sum value (idt) is greater than the maximum current
(crt). If a positive determination is made, the algorithm may
proceed to step 5308, in which the value of a block register
(iBlock) may be augmented. The block register value augmentation
may be representative of the possibility that the motor is blocked.
Hence, the higher the value of block register is, the more likely
that the motor blockage has occurred.
[0321] On the other hand, if a negative determination is made in
step 5308, the algorithm may proceed to step 5312, in which the
value of the block register (iBlock) may be compared with a
predefined value. If the value of the block register is less than
the predefined value, a reduction step 5316 may be executed for
reducing the value of the block register. In one embodiment, the
value of the block register may be a negative number. If the value
of the block register is greater than the predefined value, an
increment step 5314 may be executed for augmenting the value of the
block register.
[0322] In step 5320, a determination is made regarding whether a
motor blockage has occurred. The value of the block register may be
compared with a predefined threshold. The predefined threshold may
represent a threshold probability that a motor blockage has
occurred. If the value of the block register does not reach the
predefined threshold, the algorithm may assume no motor blockage
has happened yet, and it may return to step 5302 for the next motor
sequence. However, if the value of the block register exceeds the
predefined threshold, the algorithm may determine that the motor is
blocked, and it may enter a different sequence.
[0323] Once a motor blockage is detected, the implant electronic
device may direct the motor to decrease its speed and to enhance
the motor torque. In one embodiment, for example, the implant
electronic device may decrease the pulse duration to about 1.2 ms
to produce more motor torque. If the motor load decreases, thereby
requiring less motor torque, the implant electronic device may
direct the motor to increase its speed again.
[0324] The discussion now turns to several gastric band components.
Referring to FIGS. 58A-58C, various views of a bendable skeleton
5800 may be shown according to an embodiment of the present
invention. Generally, the bendable skeleton 5800 may be used for
implementing the functional features of the skeleton 3814. The
bendable skeleton may be made of a PEEK material, which may be
corrosion resistive and durable against stress.
[0325] The bendable skeleton 5800 may have an open compartment 5802
for receiving and securing the motor, a ladder body 5804 for
supporting the dorsal ring surface of the gastric band, and a
distal end member 5806 for providing an anchor point for the hook
end (element) 5602 of the flexible screw 5600 to the first end of
the dorsal element. The ladder body 5804 may also embrace the
stabilizing tube 5820. In return, the stabilizing tube 5802 may
guide the center wire of the flexible screw assembly to travel from
the open compartment 5802 to the distal end member 5806 of the
bendable skeleton 5800.
[0326] The open compartment 5802 may have a diameter 5808, a
vertical distance 5810 separating the open compartment 5802 and the
distal end member 5806, and an overall length 5812. In one
embodiment, the diameter 5805 may be about 13.6 mm, the vertical
distance 5810 may be about 67.6 mm, and the overall length 5812 may
be about 111.23 mm.
[0327] FIGS. 59A-59B show a perspective view and a cross-sectional
view of the stabilizing tube 5820 according to an embodiment of the
present invention. Generally, the stabilizing tube 5820 may be made
of an ePTFE material. The stabilizing tube 5820 may have an overall
length 5912, a first height 5914, a second height 5916, a radius
5922, a thickness 5920, and a channel radius 5918. In one
embodiment, the overall length 5912 may be about 130 mm, the first
height 5914 may be about 2.55 mm, the second height 5916 may be
about 4.4 mm, the radius 5922 may be about 5 mm, the thickness 5920
may be about 3.5 mm, and the channel diameter 5918 may be about 3
mm.
[0328] FIGS. 60A-60D show various views of a dorsal element 6000
according to an embodiment of the present invention. Generally, the
dorsal element 6000 may be used for implementing the functional
features of the dorsal element 3704 as shown in FIG. 37B. The
dorsal element 6000 may include an open compartment 6001, an
opening 6002, and a semi-tubular ring (body) 6022 connecting the
open compartment 6001 and the opening 6002. The side wall of the
open compartment 6001 may have a locking protrusion and a
ring-locked indicator 6030 formed on the locking protrusion. During
the band formation, the open compartment 6001 may be inserted into
the opening 6002, which may have a clip ring with a locking flange
6006. The locking flange may have a port for securing the locking
protrusion. Once the locking protrusion is secured by the flange
port, the ring-lock indicator 6030 may become visible.
[0329] FIGS. 61A-61C show various views of an anti-slip cushion
6100 according to an embodiment of the present invention. The
cushion 6100 may have a width 6102, a thickness 6104, a first
length 6106, and a second length 6110. In one embodiment, the width
6102 may be about 17.92 mm, the thickness 6104 may be about 4.42
mm, the first length 6106 may be about 17.3 mm, and the second
length 6110 may be slightly shorter than the first length 6106.
[0330] The front surface of the cushion 6100 may be symmetrical
along a vertical axis, and it may have a convex shield-like surface
with an array of curvy groove lines 6108 to provide more friction.
Advantageously, the curvy groove lines 6108 may help the gastric
band to remain in contact with the patient stomach and reduce the
likelihood of band slippage. Moreover, the shield-like convex
surface of the cushion 6100 may efficiently stimulate the valgus
nerve of the patient.
[0331] FIGS. 62A-62C show various views of a membrane shell 6200
according to an embodiment of the present invention. In general,
the membrane shell 6200 may include a tubular structure made of
several segments 6208. The tubular structure 6202 may have a
circular contour, and it may be used for encapsulating the dorsal
element 6000, the skeleton 5800, and part of the flexible screw
5600. The segments 6208 may be used for receiving the cushions
6100. The membrane shell 6200 may be made of several NuSil LSR
silicones, depending on the level of hardness it is designed to
achieve. In one embodiment, for example, the membrane shell 6200
may be made of MED-4870, which is a silicone with a hardness of
about 70 Shore A.
[0332] FIGS. 63A-63C show various views of a cushioned membrane
shell 6300 according to an embodiment of the present invention. The
cushioned membrane shell 6300 may include several cushions 6308,
which may be made of MED-4801. When compared to MED-4870, MED-4801
may have a hardness of about 1 Shore A. Accordingly, the cushioned
membrane shell 6300 may have a soft inner circumferential surface
and a hard outer circumferential surface.
[0333] In an alternative embodiment, the cushions 6308 may be made
of a silicone elastomer external shell filled with saline solution
or made of a silicone elastomer external shell filled with silicone
gel. Specifically, the silicone elastomer for the cushions may have
a hardness ranges from about 1 Shore A to about 10 Shore A, whereas
the silicone elastomer for the membrane shell may have a hardness
ranges from about 20 Shore A to about 45 Shore A.
[0334] Unless otherwise indicated, all numerical parameters used in
the specification and claims are to be understood as being modified
in all instances by the term "about." Accordingly, unless indicated
to the contrary, the numerical parameters set forth in the
specification and attached claims are approximations that may vary
depending upon the desired properties sought to be obtained by the
present invention. At the very least, and not as an attempt to
limit the application of the doctrine of equivalents to the scope
of the claims, each numerical parameter should at least be
construed in light of the number of reported significant digits and
by applying ordinary rounding techniques. Notwithstanding that the
numerical ranges and parameters setting forth the broad scope of
the present invention are approximations, the numerical values set
forth in the specific examples are reported as precisely as
possible. Any numerical value, however, inherently contains certain
errors necessarily resulting from the standard deviation found in
their respective testing measurements.
[0335] The terms "a," "an," "the," and similar referents used in
the context of describing the present invention (especially in the
context of the following claims) are to be construed to cover both
the singular and the plural, unless otherwise indicated herein or
clearly contradicted by context. Recitation of ranges of values
herein is merely intended to serve as a shorthand method of
referring individually to each separate value falling within the
range. Unless otherwise indicated herein, each individual value is
incorporated into the specification as if it were individually
recited herein. All methods described herein can be performed in
any suitable order unless otherwise indicated herein or otherwise
clearly contradicted by context. The use of any and all examples,
or exemplary language (e.g., "such as") provided herein is intended
merely to better illuminate the present invention and does not pose
a limitation on the scope of the present invention otherwise
claimed. No language in the specification should be construed as
indicating any non-claimed element essential to the practice of the
present invention.
[0336] Groupings of alternative elements or embodiments of the
invention disclosed herein are not to be construed as limitations.
Each group member may be referred to and claimed individually or in
any combination with other members of the group or other elements
found herein. It is anticipated that one or more members of a group
may be included in, or deleted from, a group for reasons of
convenience and/or patentability. When any such inclusion or
deletion occurs, the specification is deemed to contain the group
as modified thus fulfilling the written description of all Markush
groups used in the appended claims.
[0337] Certain embodiments of this invention are described herein,
including the best mode known to the inventors for carrying out the
invention. Of course, variations on these described embodiments
will become apparent to those of ordinary skill in the art upon
reading the foregoing description. The inventor expects skilled
artisans to employ such variations as appropriate, and the
inventors intend for the invention to be practiced otherwise than
specifically described herein. Accordingly, this invention includes
all modifications and equivalents of the subject matter recited in
the claims appended hereto as permitted by applicable law.
Moreover, any combination of the above-described elements in all
possible variations thereof is encompassed by the invention unless
otherwise indicated herein or otherwise clearly contradicted by
context.
[0338] Furthermore, certain references have been made to patents
and printed publications throughout this specification. Each of the
above-cited references and printed publications are individually
incorporated herein by reference in their entirety.
[0339] Specific embodiments disclosed herein may be further limited
in the claims using consisting of or consisting essentially of
language. When used in the claims, whether as filed or added per
amendment, the transition term "consisting of" excludes any
element, step, or ingredient not specified in the claims. The
transition term "consisting essentially of" limits the scope of a
claim to the specified materials or steps and those that do not
materially affect the basic and novel characteristic(s).
Embodiments of the invention so claimed are inherently or expressly
described and enabled herein.
[0340] In closing, it is to be understood that the embodiments of
the present invention disclosed herein are illustrative of the
principles of the present invention. Other modifications that may
be employed are within the scope of the present invention. Thus, by
way of example, but not of limitation, alternative configurations
of the present invention may be utilized in accordance with the
teachings herein. Accordingly, the present invention is not limited
to that precisely as shown and described.
* * * * *