U.S. patent application number 11/959229 was filed with the patent office on 2008-04-24 for magnetic sensor for a transducer.
Invention is credited to Steven E. Boor.
Application Number | 20080095391 11/959229 |
Document ID | / |
Family ID | 32659392 |
Filed Date | 2008-04-24 |
United States Patent
Application |
20080095391 |
Kind Code |
A1 |
Boor; Steven E. |
April 24, 2008 |
Magnetic Sensor for a Transducer
Abstract
A system and method for assisting listening wherein an
integrated circuit selects one or more audio sources from among a
plurality audio sources to be presented to a signal processing
circuit. Selection of the audio source can be automatically
executed in response to detection of an external magnetic field,
such as from a telephone handset, or manually controlled by a user
input.
Inventors: |
Boor; Steven E.; (Plano,
TX) |
Correspondence
Address: |
MARSHALL, GERSTEIN & BORUN LLP;Suite 6300
Sears Tower
233 S. Wacker Drive
Chicago
IL
60606-6357
US
|
Family ID: |
32659392 |
Appl. No.: |
11/959229 |
Filed: |
December 18, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11464641 |
Aug 15, 2006 |
7317997 |
|
|
11959229 |
Dec 18, 2007 |
|
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|
10736151 |
Dec 15, 2003 |
7162381 |
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11464641 |
Aug 15, 2006 |
|
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|
60433486 |
Dec 13, 2002 |
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Current U.S.
Class: |
381/326 |
Current CPC
Class: |
H04R 25/603 20190501;
H04R 25/554 20130101; H04R 25/502 20130101; H04R 25/43 20130101;
H04R 2225/61 20130101 |
Class at
Publication: |
381/326 |
International
Class: |
H04R 25/00 20060101
H04R025/00 |
Claims
1. An assisted-listening device comprising: two or more audio
sources adapted to provide an audio signal; a signal processing
circuit adapted to process the audio signal provided by the audio
sources; and an integrated circuit disposed in one of the audio
sources, the integrated circuit including a sensor and a magnetic
field threshold comparator for detecting an external magnetic field
presence and a magnetic field threshold, the magnetic field
threshold comparator including an output; wherein the magnetic
field threshold comparator output being operably coupled to the
signal processing circuit changes in response to the sensed
external magnetic field.
2. The assisted-listening device of claim 1, wherein the integrated
circuit further comprises: a gate including two or more audio
source inputs, and an output, the gate being adapted to select one
or more of the inputs in response to the sensed external magnetic
field and the gate output being operably connected to the signal
processing circuit.
3. The assisted-listening device of claim 2, wherein the integrated
circuit further comprises: a magnetic field threshold value
operably coupled to the magnetic field threshold comparator, the
comparator operably coupled to the sensor and adapted to provide to
the signal processing circuit one or more of the audio source
inputs to the gate in response to the sensed external magnetic
field and the magnetic field threshold value.
4. The assisted-listening device of claim 1, wherein the integrated
circuit further comprises: a manual override for allowing one or
more audio source signals to be presented to the signal processing
circuit.
5. The assisted-listening device of claim 1, wherein the sensor is
selected from the group consisting of a lateral bipolar
magnetotransistor (LBMT), a split-drain MAGFET, a Hall effect
sensor, a microelectromechanical system (MEMS) device, and an
active telecoil.
6. The assisted-listening device of claim 1, wherein the sensor has
a power consumption of substantially 100 .mu.W or less.
7. The assisted-listening device of claim 1, wherein one or more of
the audio sources is an electroacoustic transducer, an
electromagnetic transducer, or combination thereof.
8. The assisted-listening device of claim 7, wherein the
electroacoustic transducer is a microphone.
9. The assisted-listening device of claim 7, wherein the
electromagnetic transducer is a telecoil.
10. The assisted listening device of claim 3, wherein the
integrated circuit further comprises: a signal shaping device
operably coupled to the signal processing circuit.
11. The assisted-listening device of claim 10, wherein the signal
shaping device is selected from the group consisting of biasing,
amplifying, filtering, and rectifying devices.
12. A device comprising: a transducer adapted to provide a signal;
and a sensor for detecting an external magnetic field presence is
disposed in the transducer.
13. The device of claim 12, further comprising: a magnetic field
threshold comparator and a magnetic field threshold value, the
magnetic field threshold comparator being operably coupled to the
sensor and the magnetic field threshold value; and a gate adapted
to provide an output signal in response to the sensor detecting the
presence of the external magnetic field; wherein the magnetic field
threshold comparator, the magnetic field threshold value, and the
gate are disposed in the transducer.
14. The device of claim 13, further comprising: a signal processing
circuit operably coupled to an output of the gate.
15. The device of claim 13, further comprising: one or more
additional transducers adapted to provide at least one signal, the
gate being adapted to select one or more signals in response to the
sensed external magnetic field.
16. The device of claim 15, further comprising: a signal processing
circuit operably coupled to the output of the gate.
17. The device of claim 15, further comprising: a manual override
for allowing one or more signals to be output from the gate.
18. The device of claim 16, further comprising: a manual override
for allowing one or more signals to be presented to the signal
processing circuit.
19. The device of claim 12, wherein the sensor is selected from the
group consisting of a lateral bipolar magnetotransistor (LBMT), a
split-drain MAGFET, a Hall effect sensor, a microelectromechanical
system (MEMS) device, and an active telecoil.
20. The device of claim 12, wherein the sensor has a power
consumption of substantially 100 .mu.W or less.
21. The device of claim 12, wherein the transducer is a microphone
or a telecoil.
22. The device of claim 15, wherein one or more of the transducers
is a microphone, a telecoil, or combination thereof.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent is a continuation of U.S. Ser. No. 11/464,641,
filed Aug. 15, 2006, which is a continuation of U.S. Ser. No.
10/736,151, filed Dec. 15, 2003, which claims the benefit of U.S.
Provisional Patent Application No. 60/433,486, filed Dec. 13, 2002,
the disclosures of which are hereby incorporated herein by
reference in its entirety for all purposes.
TECHNICAL FIELD
[0002] This patent relates to assisted-listening systems. More
specifically, this patent relates to an assisted-listening device
capable of determining and adapting to surrounding environmental
conditions.
BACKGROUND
[0003] Assisted-listening devices, e.g., hearing aids and the like,
should be capable of operating in, and being adaptable to, several
environmental conditions. For example, the assisted-listening
device should to be capable of automatically selecting amongst
various audio sources, e.g., telecoil, microphone, or auxiliary.
One commercially available hearing aid utilizes a magnetic reed
switch to provide magnetic field detection and automatic transducer
mode selection. Unfortunately, there are a number of limitations
associated with utilizing the magnetic reed switch. Frequently, the
reed switch lacks the sensitivity to operate with many types of
telephones and often requires placing an external magnet onto the
telephone handset earpiece. Additionally, the reed switch requires
use of a portion of the communicate device, such as a very limited
space within the hearing aid. Furthermore, the reed switch may be
susceptible to damage or performance changes if the hearing aid is
dropped or subjected to extremely high magnetic fields--thus
undermining the effective reliability of the assisted-listening
system. Another shortcoming involves the added costs that are
incurred to implement the reed switch into the assisted-listening
system due to the additional components and manufacturing effort
required.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] For a more complete understanding of the disclosure,
reference should be made to the following detailed description and
accompanying drawings wherein:
[0005] FIG. 1 is a schematic block diagram of an integrated circuit
in accordance with an embodiment of the invention;
[0006] FIG. 2 is a schematic block diagram of an integrated circuit
in accordance with another embodiment of the invention; and
[0007] FIG. 3 is a schematic block diagram of an integrated circuit
in accordance with still another embodiment of the invention.
DETAILED DESCRIPTION
[0008] One of the described embodiments is directed to a system and
method for assisting listening e.g. hearing devices and methods of
facilitating hearing, and the like, wherein an integrated circuit
facilitates selection of an audio source mode in response to the
detection of an external magnetic field. In the exemplary
embodiment, an integrated circuit for an assisted-listening device
is operably disposed between a plurality of audio sources and a
signal processing circuit. The integrated circuit may include a
magnetic field sensor and a threshold comparator. A gate, e.g., a
multiplexer, may be operably coupled and responsive to the output
from the magnetic field threshold comparator. The gate may include
a plurality of inputs being capable of coupling to a variety of
transducer outputs or auxiliary audio sources, e.g., magnetic
(telecoil), acoustic (microphone). In response to the presence of a
magnetic field, one of the audio sources or transducer outputs is
selected to be output to the signal processing circuit.
[0009] In an alternate described embodiment, a manual override mode
may be provided for allowing multiple audio source outputs and/or
transducer outputs to be simultaneously presented to the signal
processing circuit.
[0010] In still another described embodiment, an integrated circuit
is operably disposed between a plurality of audio sources and a
signal processing circuit. The integrated circuit may include a
sensor for detecting an external magnetic field presence. A
magnetic field threshold comparator may be operably connected to
the sensor. A gate is operably responsive to the magnetic field
threshold comparator. The gate includes a plurality of inputs and a
gate output. The plurality of inputs are connected to the plurality
of audio sources. The gate output comprises a plurality of mode
signals and is connected to the signal processing circuit. The gate
output is responsive to the magnetic field threshold comparator
such that detection of the external magnetic field enables one of
the plurality of audio source signals to be presented to the signal
processing circuit.
[0011] In another described embodiment, an integrated circuit may
include a sensor for detecting an external magnetic field presence.
A magnetic field threshold comparator may include a first input
operably connected to a magnetic field threshold value and a second
input operably connected to the sensor. The magnetic field
threshold comparator further includes an output being adaptable for
connecting to a signal processing circuit. The output comprises a
first signal and a second signal and is determined in response to
the comparison of the sensed external magnetic field and the
magnetic field threshold value wherein the first signal is
presented to the signal processing circuit when the magnetic field
threshold value exceeds the sensed external magnetic field and the
second signal is presented to the signal processing circuit when
the sensed external magnetic field exceeds the magnetic field
threshold value.
[0012] Although the following text sets forth a detailed
description of numerous different embodiments of the invention, it
should be understood that the legal scope of the invention is
defined by the words of the claims set forth at the end of this
patent. The detailed description is to be construed as exemplary
only and does not describe every possible embodiment of the
invention because describing every possible embodiment would be
impractical, if not impossible. Numerous alternative embodiments
could be implemented, using either current technology or technology
developed after the filing date of this patent, which would still
fall within the scope of the claims defining the invention.
Moreover, structure, features and functions of the herein described
embodiments should be considered interchangeable, and every
structure, feature or function may be used with any of the
embodiments herein described.
[0013] FIG. 1 depicts an integrated circuit 10, shown in dotted
lines, operably disposed between a plurality of audio sources 12
and a signal processing circuit 14. The integrated circuit 10
includes an magnetic field sensor 16 a magnetic field sensor
amplifier 17 and a gate 18. The gate 18, preferably a multiplexer,
is operably responsive to the output from the magnetic field sensor
amplifier 17. The magnetic field sensor 16 may include a threshold
comparator 26 wherein detection of a magnetic field is based upon
whether the magnetic field strength detected is above or below a
threshold level. The threshold level 19 can be fixed or adjustable.
The magnetic field sensor amplifier 17 provides an output signal to
the gate 18 to ensure desired operation.
[0014] The gate 18 includes a plurality of inputs 20 for receiving
the outputs of transducers or auxiliary audio sources, e.g.,
magnetic (telecoil) 12 via coupled magnetic telecoil amplifier 28,
acoustic (microphone) 13.
[0015] FIG. 2 depicts an alternate embodiment of an integrated
circuit 10'. It is to be understood that the present invention may
be embodied in these and other configurations. Circuit design
preferences, manufacturing constraints, etc., are only a few of the
many parameters that may influence whether certain devices, e.g.,
gate 18, are to be included in the configuration of the integrated
circuit.
[0016] The integrated circuit 10' includes a magnetic field sensor
16' that integrates therewith the magnetic field sensor 15 and a
magnetic filed sensor amplifier 17'. An output of the magnetic
field sensor 16' is coupled to a threshold comparator 26 which also
couples a threshold value input 19'. The output of the threshold
comparator 26 is then coupled to the gate 18. The threshold level
again may be fixed or adjustable. FIG. 3. depicts an alternate
embodiment of an integrated circuit 10'' including a magnetic field
sensor 16'' having a magnetic field sensor 17'', similar to that
illustrated in FIG. 2 as integrated circuit 10'. As shown in FIG.
3, signal shaping devices 29, e.g., biasing elements, amplifiers,
filters, rectifiers, etc., and other circuit devices may also be
incorporated in the design of the integrated circuit 10''.
[0017] Any of the embodiments of the integrated circuit 10, 10' and
10'' may further include a manual override 24, which allows one or
more than one of the plurality of inputs 20 to be manually selected
and presented to the signal processing circuit 14.
[0018] Several techniques may be utilized to detect the presence of
the external magnetic field--often referred to as a B-field--for
the control of the gate 18, e.g., microphone-telecoil multiplexer
(MT MUX) in presenting a signal to the signal processing circuit
14. Some B-field detection methods include, but are not limited to:
[0019] detection of a static B-field above or below a certain
threshold level (the detection level can be hysteretic to guard
against oscillatory behavior); [0020] detection of the AC EMF
generated by the telecoil when merely bringing the telephone
handset into close proximity of the telecoil; [0021] detection of
the AC EMF generated by the telecoil in response to the audio
signal transmitted by a telephone handset or a room loop; or,
[0022] any combination of the above.
[0023] The static B-field detection method may be preferred because
it is more robust in the presence of electromagnetic interference
(EMI)--either environmental or man-made. The other external B-field
detection methods are susceptible to "false" B-field detection from
EMI, which may result in an undesirable transducer mode selection
change that would require user intervention to correct. Although
all three detection methods may initially respond unfavorably to
EMI, the first method is capable of automatically reverting back to
proper transducer mode operation without user intervention once the
EMI event has subsided.
[0024] Another advantage of the static B-field detection method is
that it can be configured with amplifiers which operate only at low
frequencies, i.e., a very low bandwidth requirement, on the order
of 10 Hz. This is very advantageous for the development of a
detector and control circuit which operate with minimum power
consumption.
[0025] There are several possible semiconductors, e.g., solid-state
silicon, devices that could be utilized as detectors for the static
B-field of a telephone handset. The silicon external B-field
detectors may include: a lateral bipolar magnetotransistor (LBMT),
a split-drain MAGFET, or a micro-electromechanical system (MEMS)
type device. A standard Hall effect sensor may also be
utilized.
[0026] Advantages of using the LBMT are: it is a very sensitive
silicon device for the detection of B-fields; it is less noisy than
the MAGFET device; and, it detects B-fields that are tangential to
the silicon surface--which would be in the same direction as the
maximum sensitivity of the telecoil, when using standard mounting
methods to attach the IC to the body of the telecoil. Unlike the
LBMT, the MAGFET and standard Hall effect sensor are sensitive to
B-fields that are perpendicular to the silicon surface. This is a
potential disadvantage for the LBMT that may require non-standard
mounting techniques to attach the IC to the telecoil body to ensure
that the telecoil has the same maximum B-field sensitivity
orientation direction as the sensor device.
[0027] For assisted-listening device applications, power
consumption of the B-field sensor should be 100 microwatts or less
to extend the battery life of the hearing aid as much as possible.
At this power level, it is possible that the MAGFET may also
provide adequate sensitivity for use as a B-field sensor since
LBMTs are routinely operated at milliwatt power levels to obtain
high B-field detection sensitivity. However, the LBMT could be
operated at a low duty cycle to save power, since the B-field
detection circuitry does not require continuous operation.
[0028] Because both the LBMT and the split-drain MAGFET can be
utilized to generate a differential current output that is
proportional to the B-field strength, either device could be
readily integrated into the same silicon integrated circuit with a
telecoil preamplifier commonly incorporated in assisted-listening
devices. The other amplifier circuitry needed to convert the
detector differential current output into a digital
signal--utilized to control the transducer selection mode needed
for MT MUX operation--could also be easily integrated into the same
silicon IC with all of the above circuitry. Note that a standard
Hall effect sensor operates in voltage mode, so an alternative
voltage based signal processing architecture would be necessary to
generate the desired control signal for MT MUX operation.
[0029] It is to be understood that embodiments and implementations
of the invention are not limited to the particular magnetic field
detection method, and the implementation of other semiconductor
devices for magnetic field detection is within the scope of the
present invention.
[0030] In addition, an override switch can be utilized to control
MT MUX operation and provide a user the ability to manually select
a mode of operation that allows both the telecoil and microphone
outputs--or other audio sources--to be presented simultaneously to
the signal processing circuit of an assisted-listening device. This
feature is desirable in listening environments such as churches,
auditoriums, and classrooms that are often wired with magnetic room
loops to assist the hearing impaired wherein hearing aid users can
simultaneously utilize the magnetic and the acoustic audio
information supplied in these situations.
[0031] As discussed above, many of the limitations of today's
assisted-listening devices are addressed by the described
embodiments. For example, each of the embodiments is capable of
being readily incorporated with telecoil preamplifier electronics
in "active telecoil" transducers at very low cost onto the same
integrated circuit. Additional benefits that may include: [0032]
providing the ability to automatically detect whether a telephone
handset is in close proximity; [0033] providing the ability to
automatically select the appropriate audio source, i.e., microphone
output, to be output to the signal processing circuitry of an
assisted-listening device when the external magnetic field strength
is less than a predetermined threshold level; [0034] providing the
ability to automatically select the appropriate audio source, i.e,
telecoil output, to be output to the signal processing circuitry of
an assisted-listening device when the external magnetic field
strength is greater than a predetermined threshold level; [0035]
providing improved assisted-listening device reliability through an
integrated circuit design that is more resilient and less
susceptible to damage or performance shifts; [0036] efficiently
utilizing existing available space within the assisted-listening
device; and, [0037] reducing the complexity and cost of the
assembly process for assisted-listening device manufacturers by
reducing the number of device components.
[0038] Other modifications and alternative embodiments of the
invention will be apparent to those skilled in the art in view of
the foregoing description. This description is to be construed as
illustrative only, and is for the purpose of teaching those skilled
in the art the best mode of carrying out the invention. The details
of the structure and method may be varied substantially without
departing from the spirit of the invention, and the exclusive use
of all modifications which come within the scope of the appended
claims is reserved.
* * * * *