U.S. patent application number 15/013493 was filed with the patent office on 2017-07-13 for mobile device charger for charging mobile device and related adaptive charging voltage generator.
This patent application is currently assigned to Richtek Technology Corporation. The applicant listed for this patent is Richtek Technology Corporation. Invention is credited to Isaac Y. CHEN, Tzu-Chen LIN, Jing-Meng LIU, Ta-Yung YANG.
Application Number | 20170201101 15/013493 |
Document ID | / |
Family ID | 56350332 |
Filed Date | 2017-07-13 |
United States Patent
Application |
20170201101 |
Kind Code |
A1 |
YANG; Ta-Yung ; et
al. |
July 13, 2017 |
MOBILE DEVICE CHARGER FOR CHARGING MOBILE DEVICE AND RELATED
ADAPTIVE CHARGING VOLTAGE GENERATOR
Abstract
An adaptive charging voltage generator of a mobile device
charger includes: a power receiving interface for receiving a DC
voltage and a cable current from a cable; a terminal communication
interface for transmitting a charging voltage and a charging
current to a connection terminal of the mobile device charger and
for receiving a communication signal generated by the mobile device
from the connection terminal; a buck converter for receiving the DC
voltage and the cable current from the power receiving interface
and for generating the charging voltage and the charging current,
wherein the charging voltage is lower than the DC voltage while the
charging current is greater than the cable current; and a charging
voltage control circuit coupled with the buck converter and
configured for controlling the buck converter according to the
communication signal.
Inventors: |
YANG; Ta-Yung; (Taoyuan
City, TW) ; LIU; Jing-Meng; (Hsinchu County, TW)
; CHEN; Isaac Y.; (Hsinchu County, TW) ; LIN;
Tzu-Chen; (Changhua County, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Richtek Technology Corporation |
Chupei City |
|
TW |
|
|
Assignee: |
Richtek Technology
Corporation
Chupei City
TW
|
Family ID: |
56350332 |
Appl. No.: |
15/013493 |
Filed: |
February 2, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62277737 |
Jan 12, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02J 7/0044 20130101;
G06F 1/266 20130101; H02J 7/0042 20130101; H02J 7/0072 20130101;
H02M 3/158 20130101; H02J 2207/20 20200101; H02M 2001/007 20130101;
H02J 7/00 20130101; H02J 7/007 20130101; H04M 19/00 20130101; H02J
2207/40 20200101; H02M 3/1584 20130101 |
International
Class: |
H02J 7/00 20060101
H02J007/00 |
Claims
1. A mobile device charger (100) for charging a mobile device
(150), comprising: an adaptive charging voltage generator (110); a
connection terminal (120) coupled with the adaptive charging
voltage generator (110) and utilized for detachably connecting to
the mobile device (150); a cable (130) coupled with the adaptive
charging voltage generator (110); and a power source unit (140)
connected to the cable (130) and utilized for supplying a DC
voltage (VA) and a cable current (IA) to the cable (130); wherein
the adaptive charging voltage generator (110) comprises: a power
receiving interface (210) arranged to operably receive the DC
voltage (VA) and the cable current (IA) from the cable (130); a
terminal communication interface (220) arranged to operably
transmit a charging voltage (VB) and a charging current (IB) to the
connection terminal (120) and to operably receive a communication
signal (X1B; X2B) generated by the mobile device (150) from the
connection terminal (120); a buck converter (230), coupled between
the power receiving interface (210) and the terminal communication
interface (220), arranged to operably receive the DC voltage (VA)
and the cable current (IA) from the power receiving interface (210)
and to operably generate the charging voltage (VB) and the charging
current (IB), wherein the charging voltage (VB) is lower than the
DC voltage (VA) while the charging current (IB) is greater than the
cable current (IA); and a charging voltage control circuit (260),
coupled with the terminal communication interface (220) and the
buck converter (230), arranged to operably control the buck
converter (230) according to the communication signal (X1B;
X2B).
2. The mobile device charger (100) of claim 1, wherein the adaptive
charging voltage generator (110) further comprises: a first ADC
(240), coupled with the charging voltage control circuit (260),
arranged to operably generate a first digital signal (DS1)
corresponding to at least one of the charging voltage (VB) and the
charging current (IB); wherein the charging voltage control circuit
(260) controls the buck converter (230) according to the
communication signal (X1B; X2B) and further in view of the first
digital signal (DS1).
3. The mobile device charger (100) of claim 1, wherein the adaptive
charging voltage generator (110) further comprises: a temperature
sensor (250), coupled with the charging voltage control circuit
(260), arranged to operably sense temperature of the connection
terminal (120); wherein the charging voltage control circuit (260)
controls the buck converter (230) according to the communication
signal (X1B; X2B) and further in view of a sensing result of the
temperature sensor (250).
4. The mobile device charger (100) of claim 3, wherein the adaptive
charging voltage generator (110) further comprises: a first ADC
(240), coupled with the charging voltage control circuit (260),
arranged to operably generate a first digital signal (DS1)
corresponding to at least one of the charging voltage (VB) and the
charging current (IB); wherein the charging voltage control circuit
(260) controls the buck converter (230) according to the
communication signal (X1B; X2B), the sensing result of the
temperature sensor (250), and further in view of the first digital
signal (DS1).
5. The mobile device charger (100) of claim 3, wherein the charging
voltage control circuit (260) controls the buck converter (230) to
reduce at least one of the charging voltage (VB) and the charging
current (IB) when the temperature of the connection terminal (120)
increases.
6. The mobile device charger (100) of claim 3, wherein the charging
voltage control circuit (260) controls the buck converter (230) to
reduce at least one of the charging voltage (VB) and the charging
current (IB) when the temperature of the connection terminal (120)
exceeds a predetermined threshold level.
7. The mobile device charger (100) of claim 1, wherein the charging
voltage control circuit (260) is further coupled with the power
receiving interface (210), and arranged to operably control the
power source unit (140) through the power receiving interface (210)
and the cable (130) according to the communication signal (X1B;
X2B); wherein the power source unit (140) generates the DC voltage
(VA) and the cable current (IA) under control of the charging
voltage control circuit (260).
8. The mobile device charger (100) of claim 7, wherein the adaptive
charging voltage generator (110) further comprises: a first ADC
(240), coupled with the charging voltage control circuit (260),
arranged to operably generate a first digital signal (DS1)
corresponding to at least one of the charging voltage (VB) and the
charging current (IB); wherein the charging voltage control circuit
(260) instructs the power source unit (140) to adjust at least one
of the DC voltage (VA) and the cable current (IA) according to the
communication signal (X1B; X2B) and further in view of the first
digital signal (DS1).
9. The mobile device charger (100) of claim 7, wherein the adaptive
charging voltage generator (110) further comprises: a temperature
sensor (250), coupled with the charging voltage control circuit
(260), arranged to operably sense temperature of the connection
terminal (120); wherein the charging voltage control circuit (260)
instructs the power source unit (140) to adjust at least one of the
DC voltage (VA) and the cable current (IA) according to the
communication signal (X1B; X2B) and further in view of a sensing
result of the temperature sensor (250).
10. The mobile device charger (100) of claim 9, wherein the
adaptive charging voltage generator (110) further comprises: a
first ADC (240), coupled with the charging voltage control circuit
(260), arranged to operably generate a first digital signal (DS1)
corresponding to at least one of the charging voltage (VB) and the
charging current (IB); wherein the charging voltage control circuit
(260) instructs the power source unit (140) to adjust at least one
of the DC voltage (VA) and the cable current (IA) according to the
communication signal (X1B; X2B), the sensing result of the
temperature sensor (250), and further in view of the first digital
signal (DS1).
11. The mobile device charger (100) of claim 9, wherein the
charging voltage control circuit (260) instructs the power source
unit (140) to reduce at least one of the DC voltage (VA) and the
cable current (IA) when the temperature of the connection terminal
(120) increases.
12. The mobile device charger (100) of claim 9, wherein the
charging voltage control circuit (260) instructs the power source
unit (140) to reduce at least one of the DC voltage (VA) and the
cable current (IA) when the temperature of the connection terminal
(120) exceeds a predetermined threshold level.
13. The mobile device charger (100) of claim 1, wherein the cable
(130) is a USB (Universal Serial Bus) cable, while the
communication signal (X1B; X2B) is selected from D+ and D- signals
defined by USB series specifications.
14. The mobile device charger (100) of claim 1, wherein the cable
(130) is a USB cable, while the communication signal (X1B; X2B) is
selected from CC1 and CC2 signals defined by USB-PD (Universal
Serial Bus Power Delivery) series specifications.
15. The mobile device charger (100) of claim 1, wherein the
charging current (IB) is greater than 5 A.
16. The mobile device charger (100) of claim 1, wherein the buck
converter (230) comprises: a first power stage (510) arranged to
operably receive the DC voltage (VA); a second power stage (520)
arranged to operably receive the DC voltage (VA) and configured in
parallel connection with the first power stage (510); an output
capacitor (420), coupled with outputs of the first power stage
(510) and the second power stage (520), arranged to operably
provide the charging voltage (VB) and the charging current (IB); a
feedback circuit (430), coupled with the output capacitor (420),
arranged to operably generate a feedback signal (FB) according to
at least one of the charging voltage (VB) and the charging current
(IB); and a power stage control circuit (540), coupled with the
first power stage (510), the second power stage (520), and the
feedback circuit (430), arranged to operably control energy
conversion operations of the first power stage (510) and the second
power stage (520) according to the feedback signal (FB) under
control of the charging voltage control circuit (260).
17. The mobile device charger (100) of claim 16, wherein each of
the first power stage (510) and the second power stage (520) is a
synchronous power stage and comprises: an upper switch (511; 521),
comprising a first terminal for receiving the DC voltage (VA); a
lower switch (513; 523), wherein a first terminal of the lower
switch (513; 523) is coupled with a second terminal of the upper
switch (511; 521), while a second terminal of the lower switch
(513; 523) is coupled with a fixed-level terminal; and an inductor
(515; 525), wherein a first terminal of the inductor (515; 525) is
coupled with the second terminal of the upper switch (511; 521) and
the first terminal of the lower switch (513; 523), while a second
terminal of the inductor (515; 525) is coupled with the output
capacitor (420); wherein the power stage control circuit (540)
alternatively turns on the upper switch (511; 521) and the lower
switch (513; 523).
18. The mobile device charger (100) of claim 1, wherein there is no
switch device positioned on a current path between the power
receiving interface (210) and an input terminal of the buck
converter (230).
19. The mobile device charger (100) of claim 1, wherein the power
source unit (140) is an adapter, a power bank, a car charger, or a
display monitor.
20. The mobile device charger (100) of claim 1, wherein the mobile
device (150) comprises: a connector (152) for detachably connecting
with the connection terminal (120) of the mobile device charger
(100) to receive the charging voltage (VB) and the charging current
(IB) from the connection terminal (120); a battery (154); and a
battery charging circuit (156), comprising: a switch device (310),
coupled between the connector (152) and the battery (154), arranged
to selectively conduct the charging voltage (VB) and the charging
current (IB) to the battery (154) under control of a switch signal
(SW); a second ADC (320), arranged to operably generate a second
digital signal (DS2) corresponding to at least one of a battery
input voltage (Vbat) and a battery input current (that) of the
battery (154); and a battery charging circuit controller (330),
coupled with the connector (152), the switch device (310), and the
second ADC (320), wherein the battery charging circuit controller
(330) is arranged to operably generate and transmit the
communication signal (X1B; X2B) to the mobile device charger (100)
through the connector (152), and arranged to operably generate the
switch signal (SW) according to the second digital signal
(DS2).
21. An adaptive charging voltage generator (110) of a mobile device
charger (100), wherein the mobile device charger (100) is utilized
for charging a mobile device (150) and comprises a connection
terminal (120) utilized for detachably connecting to the mobile
device (150); a cable (130); and a power source unit (140) utilized
for supplying a DC voltage (VA) and a cable current (IA) to the
cable (130), the adaptive charging voltage generator (110)
comprising: a power receiving interface (210) arranged to operably
receive the DC voltage (VA) and the cable current (IA) from the
cable (130); a terminal communication interface (220) arranged to
operably transmit a charging voltage (VB) and a charging current
(IB) to the connection terminal (120) and to operably receive a
communication signal (X1B; X2B) generated by the mobile device
(150) from the connection terminal (120); a buck converter (230),
coupled between the power receiving interface (210) and the
terminal communication interface (220), arranged to operably
receive the DC voltage (VA) and the cable current (IA) from the
power receiving interface (210) and to operably generate the
charging voltage (VB) and the charging current (IB), wherein the
charging voltage (VB) is lower than the DC voltage (VA) while the
charging current (IB) is greater than the cable current (IA); and a
charging voltage control circuit (260), coupled with the terminal
communication interface (220) and the buck converter (230),
arranged to operably control the buck converter (230) according to
the communication signal (X1B; X2B).
22. The adaptive charging voltage generator (110) of claim 21,
further comprising: a first ADC (240), coupled with the charging
voltage control circuit (260), arranged to operably generate a
first digital signal (DS1) corresponding to at least one of the
charging voltage (VB) and the charging current (IB); wherein the
charging voltage control circuit (260) controls the buck converter
(230) according to the communication signal (X1B; X2B) and further
in view of the first digital signal (DS1).
23. The adaptive charging voltage generator (110) of claim 21,
further comprising: a temperature sensor (250), coupled with the
charging voltage control circuit (260), arranged to operably sense
temperature of the connection terminal (120); wherein the charging
voltage control circuit (260) controls the buck converter (230)
according to the communication signal (X1B; X2B) and further in
view of a sensing result of the temperature sensor (250).
24. The adaptive charging voltage generator (110) of claim 23,
further comprising: a first ADC (240), coupled with the charging
voltage control circuit (260), arranged to operably generate a
first digital signal (DS1) corresponding to at least one of the
charging voltage (VB) and the charging current (IB); wherein the
charging voltage control circuit (260) controls the buck converter
(230) according to the communication signal (X1B; X2B), the sensing
result of the temperature sensor (250), and further in view of the
first digital signal (DS1).
25. The adaptive charging voltage generator (110) of claim 23,
wherein the charging voltage control circuit (260) controls the
buck converter (230) to reduce at least one of the charging voltage
(VB) and the charging current (IB) when the temperature of the
connection terminal (120) increases.
26. The adaptive charging voltage generator (110) of claim 23,
wherein the charging voltage control circuit (260) controls the
buck converter (230) to reduce at least one of the charging voltage
(VB) and the charging current (IB) when the temperature of the
connection terminal (120) exceeds a predetermined threshold
level.
27. The adaptive charging voltage generator (110) of claim 21,
wherein the charging voltage control circuit (260) is further
coupled with the power receiving interface (210), and arranged to
operably control the power source unit (140) through the power
receiving interface (210) and the cable (130) according to the
communication signal (X1B; X2B); wherein the power source unit
(140) generates the DC voltage (VA) and the cable current (IA)
under control of the charging voltage control circuit (260).
28. The adaptive charging voltage generator (110) of claim 27,
further comprising: a first ADC (240), coupled with the charging
voltage control circuit (260), arranged to operably generate a
first digital signal (DS1) corresponding to at least one of the
charging voltage (VB) and the charging current (IB); wherein the
charging voltage control circuit (260) instructs the power source
unit (140) to adjust at least one of the DC voltage (VA) and the
cable current (IA) according to the communication signal (X1B; X2B)
and further in view of the first digital signal (DS1).
29. The adaptive charging voltage generator (110) of claim 27,
further comprising: a temperature sensor (250), coupled with the
charging voltage control circuit (260), arranged to operably sense
temperature of the connection terminal (120); wherein the charging
voltage control circuit (260) instructs the power source unit (140)
to adjust at least one of the DC voltage (VA) and the cable current
(IA) according to the communication signal (X1B; X2B) and further
in view of a sensing result of the temperature sensor (250).
30. The adaptive charging voltage generator (110) of claim 29,
further comprising: a first ADC (240), coupled with the charging
voltage control circuit (260), arranged to operably generate a
first digital signal (DS1) corresponding to at least one of the
charging voltage (VB) and the charging current (IB); wherein the
charging voltage control circuit (260) instructs the power source
unit (140) to adjust at least one of the DC voltage (VA) and the
cable current (IA) according to the communication signal (X1B;
X2B), the sensing result of the temperature sensor (250), and
further in view of the first digital signal (DS1).
31. The adaptive charging voltage generator (110) of claim 29,
wherein the charging voltage control circuit (260) instructs the
power source unit (140) to reduce at least one of the DC voltage
(VA) and the cable current (IA) when the temperature of the
connection terminal (120) increases.
32. The adaptive charging voltage generator (110) of claim 29,
wherein the charging voltage control circuit (260) instructs the
power source unit (140) to reduce at least one of the DC voltage
(VA) and the cable current (IA) when the temperature of the
connection terminal (120) exceeds a predetermined threshold
level.
33. The adaptive charging voltage generator (110) of claim 21,
wherein the cable (130) is a USB (Universal Serial Bus) cable,
while the communication signal (X1B; X2B) is selected from D+ and
D- signals defined by USB series specifications.
34. The adaptive charging voltage generator (110) of claim 21,
wherein the cable (130) is a USB cable, while the communication
signal (X1B; X2B) is selected from CC1 and CC2 signals defined by
USB-PD (Universal Serial Bus Power Delivery) series
specifications.
35. The adaptive charging voltage generator (110) of claim 21,
wherein the charging current (IB) is greater than 5 A.
36. The adaptive charging voltage generator (110) of claim 21,
wherein the buck converter (230) comprises: a first power stage
(510) arranged to operably receive the DC voltage (VA); a second
power stage (520) arranged to operably receive the DC voltage (VA)
and configured in parallel connection with the first power stage
(510); an output capacitor (420), coupled with outputs of the first
power stage (510) and the second power stage (520), arranged to
operably provide the charging voltage (VB) and the charging current
(IB); a feedback circuit (430), coupled with the output capacitor
(420), arranged to operably generate a feedback signal (FB)
according to at least one of the charging voltage (VB) and the
charging current (IB); and a power stage control circuit (540),
coupled with the first power stage (510), the second power stage
(520), and the feedback circuit (430), arranged to operably control
energy conversion operations of the first power stage (510) and the
second power stage (520) according to the feedback signal (FB)
under control of the charging voltage control circuit (260).
37. The adaptive charging voltage generator (110) of claim 36,
wherein each of the first power stage (510) and the second power
stage (520) is a synchronous power stage and comprises: an upper
switch (511; 521), comprising a first terminal for receiving the DC
voltage (VA); a lower switch (513; 523), wherein a first terminal
of the lower switch (513; 523) is coupled with a second terminal of
the upper switch (511; 521), while a second terminal of the lower
switch (513; 523) is coupled with a fixed-level terminal; and an
inductor (515; 525), wherein a first terminal of the inductor (515;
525) is coupled with the second terminal of the upper switch (511;
521) and the first terminal of the lower switch (513; 523), while a
second terminal of the inductor (515; 525) is coupled with the
output capacitor (420); wherein the power stage control circuit
(540) alternatively turns on the upper switch (511; 521) and the
lower switch (513; 523).
38. The adaptive charging voltage generator (110) of claim 21,
wherein there is no switch device positioned on a current path
between the power receiving interface (210) and an input terminal
of the buck converter (230).
39. The adaptive charging voltage generator (110) of claim 21,
wherein the power source unit (140) is an adapter, a power bank, a
car charger, or a display monitor.
40. The adaptive charging voltage generator (110) of claim 21,
wherein the mobile device (150) comprises: a connector (152) for
detachably connecting with the connection terminal (120) of the
mobile device charger (100) to receive the charging voltage (VB)
and the charging current (IB) from the connection terminal (120); a
battery (154); and a battery charging circuit (156), comprising: a
switch device (310), coupled between the connector (152) and the
battery (154), arranged to selectively conduct the charging voltage
(VB) and the charging current (IB) to the battery (154) under
control of a switch signal (SW); a second ADC (320), arranged to
operably generate a second digital signal (DS2) corresponding to at
least one of a battery input voltage (Vbat) and a battery input
current (that) of the battery (154); and a battery charging circuit
controller (330), coupled with the connector (152), the switch
device (310), and the second ADC (320), wherein the battery
charging circuit controller (330) is arranged to operably generate
and transmit the communication signal (X1B; X2B) to the mobile
device charger (100) through the connector (152), and arranged to
operably generate the switch signal (SW) according to the second
digital signal (DS2).
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority to U.S.
Provisional Application Ser. No. 62/277,737, filed on Jan. 12,
2016; the entirety of which is incorporated herein by reference for
all purposes.
BACKGROUND
[0002] The disclosure generally relates to a battery charger and,
more particularly, to a mobile device charger and related adaptive
charging voltage generator.
[0003] The battery capacity is always the major bottleneck to the
usage time of a mobile device. Therefore, many technologies and
materials have been developed to increase the battery capacity of
the mobile device. When the mobile device runs out of battery
power, a charging cable is typically employed by the user to
connect to the mobile device to recharge the battery.
[0004] However, the time required to charge the battery is
proportional to the capacity of the battery. For many modern mobile
devices, it may take several hours to fully recharge the battery
inside the mobile device. It is apparent that traditional charging
solutions for the mobile device are time-consuming and
inefficient.
SUMMARY
[0005] An example embodiment of a mobile device charger for
charging a mobile device is disclosed, comprising: an adaptive
charging voltage generator; a connection terminal coupled with the
adaptive charging voltage generator and utilized for detachably
connecting to the mobile device; a cable coupled with the adaptive
charging voltage generator; and a power source unit connected to
the cable and utilized for supplying a DC voltage and a cable
current to the cable. The adaptive charging voltage generator
comprises: a power receiving interface arranged to operably receive
the DC voltage and the cable current from the cable; a terminal
communication interface arranged to operably transmit a charging
voltage and a charging current to the connection terminal and to
operably receive a communication signal generated by the mobile
device from the connection terminal; a buck converter, coupled
between the power receiving interface and the terminal
communication interface, arranged to operably receive the DC
voltage and the cable current from the power receiving interface
and to operably generate the charging voltage and the charging
current, wherein the charging voltage is lower than the DC voltage
while the charging current is greater than the cable current; and a
charging voltage control circuit, coupled with the terminal
communication interface and the buck converter, arranged to
operably control the buck converter according to the communication
signal.
[0006] Another example embodiment of an adaptive charging voltage
generator of a mobile device charger is disclosed. The mobile
device charger is utilized for charging a mobile device and
comprises a connection terminal utilized for detachably connecting
to the mobile device; a cable; and a power source unit utilized for
supplying a DC voltage and a cable current to the cable. The
adaptive charging voltage generator comprises: a power receiving
interface arranged to operably receive the DC voltage and the cable
current from the cable; a terminal communication interface arranged
to operably transmit a charging voltage and a charging current to
the connection terminal and to operably receive a communication
signal generated by the mobile device from the connection terminal;
a buck converter, coupled between the power receiving interface and
the terminal communication interface, arranged to operably receive
the DC voltage and the cable current from the power receiving
interface and to operably generate the charging voltage and the
charging current, wherein the charging voltage is lower than the DC
voltage while the charging current is greater than the cable
current; and a charging voltage control circuit, coupled with the
terminal communication interface and the buck converter, arranged
to operably control the buck converter according to the
communication signal.
[0007] Both the foregoing general description and the following
detailed description are examples and explanatory only, and are not
restrictive of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 shows a simplified functional block diagram of a
mobile device charger utilized for charging a mobile device
according to one embodiment of the present disclosure.
[0009] FIG. 2 shows a simplified functional block diagram of an
adaptive charging voltage generator of the mobile device charger in
FIG. 1 according to one embodiment of the present disclosure.
[0010] FIG. 3 shows a simplified functional block diagram of a
battery charging circuit of the mobile device in FIG. 1 according
to one embodiment of the present disclosure.
[0011] FIG. 4 shows a simplified functional block diagram of a buck
converter of the adaptive charging voltage generator of FIG. 2
according to one embodiment of the present disclosure.
[0012] FIG. 5 shows a simplified functional block diagram of a buck
converter of the adaptive charging voltage generator of FIG. 2
according to another embodiment of the present disclosure.
DETAILED DESCRIPTION
[0013] Reference is made in detail to embodiments of the invention,
which are illustrated in the accompanying drawings. The same
reference numbers may be used throughout the drawings to refer to
the same or like parts, components, or operations.
[0014] FIG. 1 shows a simplified functional block diagram of a
mobile device charger 100 utilized for charging a mobile device 150
according to one embodiment of the present disclosure. As shown in
FIG. 1, the mobile device charger 100 comprises an adaptive
charging voltage generator 110, a connection terminal 120, a cable
130, and a power source unit 140. The mobile device 150 comprises a
connector 152, a battery 154, and a battery charging circuit
156.
[0015] In the mobile device charger 100, the connection terminal
120 is coupled with the adaptive charging voltage generator 110 and
utilized for detachably connecting to the connector 152 of the
mobile device 150. The cable 130 is coupled with the adaptive
charging voltage generator 110. The power source unit 140 is
connected to the cable 130. The power source unit 140 is utilized
for supplying a programmable DC voltage and a programmable current
to the cable 130 in response to an instruction data generated by
the adaptive charging voltage generator 110. Then, the adaptive
charging voltage generator 110 generates and supplies a DC charging
voltage and a charging current for charging the mobile device 150
to the connection terminal 120 based on the programmable DC voltage
and the programmable current received from the cable 130.
[0016] In the mobile device 150, the connector 152 is utilized for
detachably connecting with the connection terminal 120 of the
mobile device charger 100 to receive the charging voltage and the
charging current generated by the adaptive charging voltage
generator 110 from the connection terminal 120. The battery
charging circuit 156 is coupled with the connector 152 and the
battery 154 and utilized for controlling the charging operation of
the battery 154. For simplicity of illustration, other components
in the mobile device 150 and their connection relationships are not
illustrated in FIG. 1.
[0017] When the connection terminal 120 is connected with the
connector 152, the battery charging circuit 156 may transmit an
instruction data to the adaptive charging voltage generator 110 to
instruct the adaptive charging voltage generator 110 to supply
appropriate charging voltage and charging current to the mobile
device 150 through the connection terminal 120 and the connector
152. Upon receipt of the instruction data transmitted from the
battery charging circuit 156, the adaptive charging voltage
generator 110 generates and transmits another instruction data to
the power source unit 140 to instruct the power source unit 140 to
supply a high-voltage and low-current signal to the adaptive
charging voltage generator 110 through the cable 130. The adaptive
charging voltage generator 110 converts the high-voltage and
low-current signal supplied from the power source unit 140 into a
low-voltage and high-current signal, and then transmit the
low-voltage and high-current signal to the battery charging circuit
156 through the connection terminal 120 and the connector 152.
[0018] For example, the adaptive charging voltage generator 110 may
instruct the power source unit 140 to provide a DC voltage VA and a
cable current IA to the adaptive charging voltage generator 110
through the cable 130. The adaptive charging voltage generator 110
converts the DC voltage VA and the cable current IA into a charging
voltage VB and a charging current IB, and then transmit the
charging voltage VB and the charging current IB to the battery
charging circuit 156 through the connection terminal 120 and the
connector 152. In above situation, the DC voltage VA generated by
the power source unit 140 is higher than the charging voltage VB
generated by the adaptive charging voltage generator 110, while the
cable current IA generated by the power source unit 140 is lower
than the charging current IB generated by the adaptive charging
voltage generator 110.
[0019] Since the cable 130 only needs to transmit a small cable
current IA, the cable 130 can be realized with a thin cable, such
as a conventional USB (Universal Serial Bus) cable, instead of a
thick and short power cable.
[0020] From one aspect, the power loss of the cable 130 can be
minimized when the cable 130 is realized with a thin cable. From
another aspect, there is no special restriction to the length of
the cable 130 since the resistance of the thin cable is low.
[0021] For the purpose of explanatory convenience in the following
description, it is assumed hereinafter that the adaptive charging
voltage generator 110 may utilize communication signals X1A and X2A
to transmit instruction data to the power source unit 140, and the
battery charging circuit 156 may utilize communication signals X1B
and X2B to transmit instruction data to the adaptive charging
voltage generator 110.
[0022] In some embodiments where the cable 130 is realized with a
USB cable, the communication signals X1A and X2A as well as the
communication signals X1B and X2B may be realized with the D+ and
D- signals defined by USB series specifications.
[0023] Alternatively, the communication signals X1A and X2A as well
as the communication signals X1B and X2B may be realized with the
CC1 and CC2 signals defined by USB-PD (Universal Serial Bus Power
Delivery) series specifications.
[0024] In practice, the power source unit 140 may be realized with
a power adapter, a power bank, a car charger, a display monitor, or
any other device capable of supplying programmable DC voltage and
programmable current in response to the instruction of the adaptive
charging voltage generator 110. In some embodiments where the power
source unit 140 is realized with a power adapter, the mobile device
charger 100 may be assembled as a single data transmitting and
charging cable. In some embodiments where the power source unit 140
is realized with a power bank or a display monitor, the cable 130
may be provided with a connection terminal (not shown in FIG. 1)
for detachably connecting to the power source unit 140.
[0025] Additionally, the mobile device 150 may be realized with
various portable electronic devices, such as a mobile phone, a
tablet PC, a notebook computer, a netbook computer, a portable
video display, or the like.
[0026] Please refer to FIG. 2, which shows a simplified functional
block diagram of the adaptive charging voltage generator 110 of the
mobile device charger 100 according to one embodiment of the
present disclosure.
[0027] As shown in FIG. 2, the adaptive charging voltage generator
110 comprises a power receiving interface 210, a terminal
communication interface 220, a buck converter 230, a first ADC
(analog-to-digital converter) 240, a temperature sensor 250, and a
charging voltage control circuit 260.
[0028] The power receiving interface 210 is arranged to operably
receive the DC voltage VA and the cable current IA from the cable
130 and to operably communicate with the power source unit 140
through the cable 130. The terminal communication interface 220 is
arranged to operably transmit the charging voltage VB and the
charging current IB to the connection terminal 120 and to operably
receive the communication signals X1B and X2B generated by the
mobile device 150 from the connection terminal 120. In practice,
each of the power receiving interface 210 and the terminal
communication interface 220 may be realized with a signal bus or a
set of circuitry pins or signal pads.
[0029] The buck converter 230 is coupled between the power
receiving interface 210 and the terminal communication interface
220. The buck converter 230 is arranged to operably receive the DC
voltage VA and the cable current IA from the power receiving
interface 210 and to operably generate the charging voltage VB and
the charging current IB in response to a control signal CTRL. As
described previously, the charging voltage VB is lower than the DC
voltage VA while the charging current IB is greater than the cable
current IA.
[0030] For example, the charging current IB generated by the buck
converter 230 may be configured to be 5 A, 8 A, 10 A, or even
larger magnitude to effectively expedite the charging operation of
the mobile device 150.
[0031] Please note that there is no switch device positioned on a
current path between the power receiving interface 210 and the
input terminal of the buck converter 230.
[0032] The first ADC 240 is coupled with the output of the buck
converter 230, and arranged to operably generate a first digital
signal DS1 corresponding to at least one of the charging voltage VB
and the charging current IB.
[0033] The temperature sensor 250 is coupled with the charging
voltage control circuit 260, and arranged to operably sense
temperature of the connection terminal 120 to generate a
temperature indicator signal TS. In some embodiments, the
temperature sensor 250 may be positioned close to the connection
terminal 120.
[0034] As described previously, the connection terminal 120 is
detachably connected with the connector 152 when the mobile device
charger 100 is employed to charge the battery 154 of the mobile
device 150. During the charging operation of the battery 154, the
battery 154 and/or the battery charging circuit 156 inevitably
generate heat. Due to the volume and size restriction of the mobile
device 150, the heat dissipation device of the mobile device 150 is
not possible to immediately dissipate the heat to outside space. As
a result, the temperature of the mobile device 150 would inevitably
increase during the charging operation. Through the thermal
conduction between the connector 152 and the connection terminal
120, the temperature sensor 250 may indirectly detect the
temperature of the mobile device 150 by sensing the temperature of
the connection terminal 120.
[0035] In some embodiments where the terminal communication
interface 220 is positioned close to the connection terminal 120,
the temperature sensor 250 may be arranged close to the terminal
communication interface 220 and indirectly sense the temperature of
the connection terminal 120 through the thermal conduction between
the terminal communication interface 220 and the connection
terminal 120.
[0036] The charging voltage control circuit 260 is coupled with the
power receiving interface 210, the terminal communication interface
220, the buck converter 230, the first ADC 240, and the temperature
sensor 250. The charging voltage control circuit 260 is arranged to
operably generate the control signal CTRL according to the
communication signals X1B and X2B, the first digital signal DS1,
and further in view of the temperature indicator signal TS.
[0037] For example, when the communication signals X1B and X2B
indicates that the mobile device 150 is requesting for a higher
charging voltage and/or a larger charging current, the charging
voltage control circuit 260 may adjust the control signal CTRL to
instruct the buck converter 230 to increase the charging voltage VB
and/or the charging current IB. On the contrary, when the
communication signals X1B and X2B indicates that the mobile device
150 is requesting for a lower charging voltage and/or a smaller
charging current, the charging voltage control circuit 260 may
adjust the control signal CTRL to instruct the buck converter 230
to reduce the charging voltage VB and/or the charging current
IB.
[0038] When the charging voltage control circuit 260 determines
that the charging voltage VB and/or the charging current IB exceeds
a desired level based on the first digital signal DS1, the charging
voltage control circuit 260 may adjust the control signal CTRL to
instruct the buck converter 230 to reduce the charging voltage VB
and/or the charging current IB. On the contrary, when the charging
voltage control circuit 260 determines that the charging voltage VB
and/or the charging current IB is below a desired level based on
the first digital signal DS1, the charging voltage control circuit
260 may adjust the control signal CTRL to instruct the buck
converter 230 to increase the charging voltage VB and/or the
charging current IB.
[0039] In addition, the charging voltage control circuit 260 may
adjust the control signal CTRL to instruct the buck converter 230
to reduce the charging voltage VB and/or the charging current IB
when the temperature indicator signal TS indicates that the
temperature of the connection terminal 120 increases.
[0040] In other embodiments, the charging voltage control circuit
260 may adjust the control signal CTRL to instruct the buck
converter 230 to reduce the charging voltage VB and/or the charging
current IB when the temperature indicator signal TS indicates that
the temperature of the connection terminal 120 exceeds a
predetermined threshold level.
[0041] In addition, the charging voltage control circuit 260 is
further arranged to operably generate the communication signals X1A
and X2A according to the communication signals X1B and X2B, the
first digital signal DS1, and further in view of the temperature
indicator signal TS. As described previously, the charging voltage
control circuit 260 transmits the communication signals X1A and X2A
to the power source unit 140 through the power receiving interface
210 and the cable 130.
[0042] For example, when the communication signals X1B and X2B
indicates that the mobile device 150 is requesting for a higher
charging voltage and/or a larger charging current, the charging
voltage control circuit 260 may adjust the communication signals
X1A and X2A to instruct the power source unit 140 to increase the
DC voltage VA and/or the cable current IA. On the contrary, when
the communication signals X1B and X2B indicates that the mobile
device 150 is requesting for a lower charging voltage and/or a
smaller charging current, the charging voltage control circuit 260
may adjust the communication signals X1A and X2A to instruct the
power source unit 140 to reduce the DC voltage VA and/or the cable
current IA.
[0043] When the charging voltage control circuit 260 determines
that the charging voltage VB and/or the charging current IB exceeds
a desired level based on the first digital signal DS1, the charging
voltage control circuit 260 may adjust the communication signals
X1A and X2A to instruct the power source unit 140 to reduce the DC
voltage VA and/or the cable current IA. On the contrary, when the
charging voltage control circuit 260 determines that the charging
voltage VB and/or the charging current IB is below a desired level
based on the first digital signal DS1, the charging voltage control
circuit 260 may adjust the communication signals X1A and X2A to
instruct the power source unit 140 to increase the DC voltage VA
and/or the cable current IA.
[0044] In addition, the charging voltage control circuit 260 may
adjust the communication signals X1A and X2A to instruct the power
source unit 140 to reduce the DC voltage VA and/or the cable
current IA when the temperature indicator signal TS indicates that
the temperature of the connection terminal 120 increases.
[0045] In other embodiments, the charging voltage control circuit
260 may adjust the communication signals X1A and X2A to instruct
the power source unit 140 to reduce the DC voltage VA and/or the
cable current IA when the temperature indicator signal TS indicates
that the temperature of the connection terminal 120 exceeds a
predetermined threshold level.
[0046] In practice, the charging voltage control circuit 260 may be
realized with various digital circuits, or a combination of digital
circuits and analog circuits.
[0047] As can be appreciated from the foregoing elaborations, the
charging voltage control circuit 260 may adjust the control signal
CTRL and/or the communication signals X1A and X2A based on the
temperature indicator signal TS. Accordingly, the charging voltage
VB and charging current IB generated by the adaptive charging
voltage generator 110 can be adaptively modified based on the
thermal condition of the connector 152 or the mobile device 150.
From one aspect, the adaptive charging voltage generator 110 offers
an additional over temperature protection to the mobile device
150.
[0048] In practice, the charging voltage control circuit 260 may
utilize the communication signals X1B and X2B to report the
temperature sensing result of the temperature sensor 250 to the
battery charging circuit 156, so that the battery charging circuit
156 is enabled to have more information about the thermal condition
of the connector 152 or the mobile device 150.
[0049] Please refer to FIG. 3, which shows a simplified functional
block diagram of the battery charging circuit 156 of the mobile
device 150 according to one embodiment of the present disclosure.
The battery charging circuit 156 comprises a switch device 310, a
second ADC 320, and a battery charging circuit controller 330.
[0050] The switch device 310 is coupled between the connector 152
and the battery 154. The switch device 310 is arranged to
selectively conduct the charging voltage VB and the charging
current IB to the battery 154 under control of a switch signal
SW.
[0051] The second ADC 320 is arranged to operably generate a second
digital signal DS2 corresponding to at least one of a battery input
voltage Vbat and a battery input current that of the battery
154.
[0052] The battery charging circuit controller 330 is coupled with
the connector 152, the switch device 310, and the second ADC 320.
The battery charging circuit controller 330 is arranged to operably
generate and transmit the communication signals X1B and X2B to the
mobile device charger 100 through the connector 152 to instruct the
adaptive charging voltage generator 110 to provide appropriate
charging voltage VB and charging current IB. Additionally, the
battery charging circuit controller 330 is further arranged to
operably generate the switch signal SW according to the second
digital signal DS2, so as to control the battery input voltage Vbat
and the battery input current that.
[0053] For example, when the battery charging circuit controller
330 determines that the battery input voltage Vbat and/or the
battery input current that exceeds (or is lower than) a desired
level based on the second digital signal DS2, the battery charging
circuit controller 330 may adjust the switch signal SW to turn off
the switch device 310.
[0054] When the battery 154 is fully recharged or charged to a
predetermined level, the battery charging circuit controller 330
may adjust the switch signal SW to turn off the switch device 310
to protect the battery 154 from over charging.
[0055] FIG. 4 shows a simplified functional block diagram of the
buck converter 230 of the adaptive charging voltage generator 110
according to one embodiment of the present disclosure.
[0056] In this embodiment of FIG. 4, the buck converter 230
comprises a single power stage 410, an output capacitor 420, a
feedback circuit 430, and a power stage control circuit 440.
[0057] The power stage 410 is coupled with the input terminal of
the buck converter 230 and arranged to operably receive the DC
voltage VA. The output capacitor 420 is coupled with the output of
the power stage 410 and arranged to operably provide the charging
voltage VB and the charging current IB to the output terminal of
the buck converter 230.
[0058] In practice, the power stage 410 may be realized with a
synchronous power stage or an asynchronous power stage. For
example, as shown in FIG. 4, the power stage 410 is realized with a
synchronous power stage and comprises an upper switch 411, a lower
switch 413, and an inductor 415. The upper switch 411 comprises a
first terminal for receiving the DC voltage VA. A first terminal of
the lower switch 413 is coupled with a second terminal of the upper
switch 411, while a second terminal of the lower switch 413 is
coupled with a fixed-level terminal, such as a ground terminal A
first terminal of the inductor 415 is coupled with the second
terminal of the upper switch 411 and the first terminal of the
lower switch 413, while a second terminal of the inductor 415 is
coupled with the output capacitor 420.
[0059] The feedback circuit 430 is coupled with the output
capacitor 420 and arranged to operably generate a feedback signal
FB according to at least one of the charging voltage VB and the
charging current IB.
[0060] The power stage control circuit 440 is coupled with the
power stage 410 and the feedback circuit 430. The power stage
control circuit 440 is arranged to operably control the energy
conversion operation of the power stage 410 according to the
feedback signal FB and the control signal CTRL. For example, the
power stage control circuit 440 may generate and utilize switch
control signals S1 and S2 to respectively control the switching
operations of the upper switch 411 and the lower switch 413, so
that the charging voltage VB and the charging current IB provided
by the output capacitor 420 meets the instruction of the control
signal CTRL.
[0061] In practice, the power stage control circuit 440 may be
realized with various PWM (pulse width modulation) signal
generators or PFM (pulse frequency modulation) signal
generators.
[0062] The buck converter 230 may comprise more than one power
stage. For example, FIG. 5 shows a simplified functional block
diagram of the buck converter 230 according to another embodiment
of the present disclosure.
[0063] In the embodiment of FIG. 5, the buck converter 230
comprises multiple power stages, the output capacitor 420, the
feedback circuit 430, and a power stage control circuit 540. For
the purpose of explanatory convenience in the following
description, only two exemplary power stages (i.e., a first power
stage 510 and a second power stage 520) are illustrated in FIG.
5.
[0064] The first power stage 510 is coupled with the input terminal
of the buck converter 230 and arranged to operably receive the DC
voltage VA.
[0065] The second power stage 520 is coupled with the input
terminal of the buck converter 230 and arranged to operably receive
the DC voltage VA. In addition, the second power stage 520 is
configured in parallel connection with the first power stage
510.
[0066] The output capacitor 420 is coupled with the outputs of both
the first power stage 510 and the second power stage 520 and
arranged to operably provide the charging voltage VB and the
charging current IB.
[0067] The feedback circuit 430 is coupled with the output
capacitor 420, and arranged to operably generate a feedback signal
FB according to at least one of the charging voltage VB and the
charging current IB.
[0068] The power stage control circuit 540 is coupled with the
first power stage 510, the second power stage 520, and the feedback
circuit 430. The power stage control circuit 540 is arranged to
operably control energy conversion operations of the first power
stage 510 and the second power stage 520 according to the feedback
signal FB and the control signal CTRL.
[0069] In practice, each of the first power stage 510 and the
second power stage 520 may be realized with a synchronous power
stage or an asynchronous power stage. In the embodiment of FIG. 5,
for example, each of the first power stage 510 and the second power
stage 520 is realized with a synchronous power stage.
[0070] As shown in FIG. 5, the first power stage 510 comprises an
upper switch 511, a lower switch 513, and an inductor 515. The
upper switch 511 comprises a first terminal for receiving the DC
voltage VA. A first terminal of the lower switch 513 is coupled
with a second terminal of the upper switch 511, while a second
terminal of the lower switch 513 is coupled with a fixed-level
terminal, such as a ground terminal A first terminal of the
inductor 515 is coupled with the second terminal of the upper
switch 511 and the first terminal of the lower switch 513, while a
second terminal of the inductor 515 is coupled with the output
capacitor 420.
[0071] Similarly, the second power stage 520 comprises an upper
switch 521, a lower switch 523, and an inductor 525. The upper
switch 521 comprises a first terminal for receiving the DC voltage
VA. A first terminal of the lower switch 523 is coupled with a
second terminal of the upper switch 521, while a second terminal of
the lower switch 523 is coupled with a fixed-level terminal, such
as a ground terminal A first terminal of the inductor 525 is
coupled with the second terminal of the upper switch 521 and the
first terminal of the lower switch 523, while a second terminal of
the inductor 525 is coupled with the output capacitor 420.
[0072] The power stage control circuit 540 may generate and utilize
switch control signals 51 and S2 to alternatively turn on the upper
switch 511 and the lower switch 513 of the first power stage 510.
In addition, the power stage control circuit 540 may further
generate and utilize switch control signals Sm and Sn to
alternatively turn on the upper switch 521 and the lower switch 523
of the second power stage 520. In practice, the power stage control
circuit 540 may be realized with various PWM signal generators or
PFM signal generators.
[0073] As is well known in related art, a higher DC voltage VA may
cause a higher power loss and heat at the power stage of the buck
converter 230, such as the power stage 410 in FIG. 4 or the power
stages 510 and 520 in FIG. 5. The development trend of the mobile
device 150 is slim and compact, and thus the volume and inner space
of the mobile device 150 are very restricted. Therefore, it is very
difficult for the mobile device 150 to have sufficient space to
install heat dissipation devices required for effectively and
rapidly dissipating the heat generated by the buck converter
230.
[0074] In addition, the components inside the mobile device 150
must be very small due to the volume restriction of the mobile
device 150. Accordingly, if the mobile device manufacturer wants to
forcedly integrate a buck converter into the mobile device 150,
then the inductors of the buck converter must be very small. As a
result, the switching frequency of the power switches of the buck
converter must be high, which results more power loss at the power
switches and the inductors of the buck converter.
[0075] The buck converter 230 in this disclosure is arranged in the
adaptive charging voltage generator 110 outside the mobile device
150, and thus the buck converter 230 is allowed to use larger
inductors. In this situation, the switching frequency of the power
switches of the buck converter 230 (e.g., the switches 411, 413,
511, 513, 521, and 523) can be much lower than the case where the
buck converter is arranged inside the mobile device 150. As a
result, the power loss of the buck converter 230 can be effectively
reduced.
[0076] Due to the heat dissipation and power efficiency concerns
described above, it is obvious that the disclosed buck converter
230 is not suitable to be integrated into the mobile device
150.
[0077] As can be seen from the foregoing descriptions, the single
power stage 410 in the embodiment of FIG. 4 is replaced by multiple
power stages in the embodiment of FIG. 5. Hence, the volume and
size of each inductor in the embodiment of FIG. 5 can be smaller
than the single inductor 415 in the embodiment of FIG. 4. As a
result, the volume and size of the entire buck converter 230 of
FIG. 5 can be greatly reduced compared to the embodiment of FIG. 4.
Accordingly, the volume and size of the adaptive charging voltage
generator 110 can be effectively reduced by adopting the buck
converter 230 of FIG. 5 in comparison with the embodiment adopting
the buck converter 230 of FIG. 4.
[0078] According to the foregoing elaborations, it can be
appreciated that there is no volume and size restriction to the
components of the adaptive charging voltage generator 110 since the
adaptive charging voltage generator 110 is outside the mobile
device 150. Accordingly, there is no volume and size restriction to
the components (e.g., the inductors) of the buck converter 230
inside the adaptive charging voltage generator 110. As a result,
the switching frequency of the power switches of the buck converter
230 can be lowered to reduce the power loss at the power stages of
the buck converter 230.
[0079] In addition, since the cable 130 only needs to transmit a
small cable current IA, the cable 130 can be realized with a thin
and long cable, instead of a thick and short power cable.
[0080] Furthermore, since the disclosed adaptive charging voltage
generator 110 converts the cable current IA supplied by the power
source unit 140 into a much larger charging current IB, the
charging speed of the battery 154 can be effectively increased and
thus reduce the required time for charging the battery 154.
[0081] In addition, the adaptive charging voltage generator 110 is
able to adaptively modify the charging voltage VB and the charging
current IB according to the communication signal generated by the
mobile device 150. Accordingly, the disclosed adaptive charging
voltage generator 110 can be utilized to charge different kinds of
mobile devices, and thus can be employed in various
applications.
[0082] In some embodiments, the power source unit 140 may be
configured to simply supply the DC voltage VA at a fixed voltage
level. In this situation, the circuitry of the charging voltage
control circuit 260 may be simplified since there is no need to
generate the communication signals X1A and X2A described above.
[0083] In some embodiments, the first ADC 240 and/or the
temperature sensor 250 may be omitted to simplify the circuitry
complexity of the adaptive charging voltage generator 110.
[0084] In the previous descriptions, each of the power stages of
the buck converter 230 is realized with a synchronous power stage.
This is merely an exemplary embodiment, rather than a restriction
to the practice implementations. For example, each of the power
stages 410, 510, and 520 shown in FIG. 4 and FIG. 5 may be instead
realized to be an asynchronous power stage.
[0085] Certain terms are used throughout the description and the
claims to refer to particular components. One skilled in the art
appreciates that a component may be referred to as different names.
This disclosure does not intend to distinguish between components
that differ in name but not in function. In the description and in
the claims, the term "comprise" is used in an open-ended fashion,
and thus should be interpreted to mean "include, but not limited
to." The phrases "be coupled with," "couples with," and "coupling
with" are intended to compass any indirect or direct connection.
Accordingly, if this disclosure mentioned that a first device is
coupled with a second device, it means that the first device may be
directly or indirectly connected to the second device through
electrical connections, wireless communications, optical
communications, or other signal connections with/without other
intermediate devices or connection means.
[0086] The term "and/or" may comprise any and all combinations of
one or more of the associated listed items. In addition, the
singular forms "a," "an," and "the" herein are intended to comprise
the plural forms as well, unless the context clearly indicates
otherwise.
[0087] The term "voltage signal" used throughout the description
and the claims may be expressed in the format of a current in
implementations, and the term "current signal" used throughout the
description and the claims may be expressed in the format of a
voltage in implementations.
[0088] Other embodiments of the invention will be apparent to those
skilled in the art from consideration of the specification and
practice of the invention disclosed herein. It is intended that the
specification and examples be considered as exemplary only, with a
true scope and spirit of the invention indicated by the following
claims.
* * * * *