U.S. patent application number 14/792725 was filed with the patent office on 2015-10-29 for charging device.
The applicant listed for this patent is Renesas Electronics Corporation. Invention is credited to Takashi Makita, Mamoru Mochizuki, Yoshiharu Ono, Tsutomu Tanaka.
Application Number | 20150311729 14/792725 |
Document ID | / |
Family ID | 49157009 |
Filed Date | 2015-10-29 |
United States Patent
Application |
20150311729 |
Kind Code |
A1 |
Ono; Yoshiharu ; et
al. |
October 29, 2015 |
CHARGING DEVICE
Abstract
There is provided a charging device which can rapidly charge,
with a single charger, portable devices of a plurality of charging
specifications. A plurality of available power indicating circuits
included in a USB module 10 notify, through a data line, a portable
device coupled to the charging device of a signal indicating
suppliable amount of current. A CPU 4 obtains, from a portable
device coupled thereto, information identifying the portable
device, at the time of adjustment. A memory 6 has a table stored
therein, for a plurality of portable devices, defining a
correspondence between information identifying a portable device
and an available power indicating circuit. Referring to the table
based on the obtained information, the CPU 4 selects an available
power indicating circuit and, at the time of actual operation,
activates only the selected available power indicating circuit.
Inventors: |
Ono; Yoshiharu; (Kanagawa,
JP) ; Tanaka; Tsutomu; (Kanagawa, JP) ;
Mochizuki; Mamoru; (Tokyo, JP) ; Makita; Takashi;
(Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Renesas Electronics Corporation |
Kawasaki-shi |
|
JP |
|
|
Family ID: |
49157009 |
Appl. No.: |
14/792725 |
Filed: |
July 7, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13771322 |
Feb 20, 2013 |
|
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14792725 |
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Current U.S.
Class: |
320/106 |
Current CPC
Class: |
H02J 7/0042 20130101;
H02J 7/007 20130101; Y02E 60/10 20130101; G01R 31/385 20190101;
H02J 7/00 20130101; H02J 7/00038 20200101; H02J 7/00045 20200101;
H02J 7/00047 20200101; H01M 10/4257 20130101 |
International
Class: |
H02J 7/00 20060101
H02J007/00; G01R 31/36 20060101 G01R031/36 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 19, 2012 |
JP |
2012-062212 |
Claims
1-5. (canceled)
6. A method for charging a portable device via a universal serial
bus of a charging device, the method comprising: supplying current
to a portable device from a power supply of the charging device
through a voltage bus (VBUS); measuring the amount of current
supplied to the portable device though the voltage bus (VBUS);
notifying the portable device coupled to the charging device of a
signal indicating suppliable amount of current; obtaining
information identifying the portable device at a control unit
coupled to the portable device; selecting an available power
indicating circuit based on the obtained information by referring
to a previously stored table which defines, for a plurality of
portable devices, correspondence between information identifying
the portable devices and available power indicating circuits, and
activating only the selected available power indicating circuit at
a time of actual operation, wherein, when the control unit does not
obtain from a portable device coupled thereto information
identifying the portable device, or when an available power
indicating circuit corresponding to information identifying the
portable device is not defined in the table, the control unit
activates the available power indicating circuits one by one,
causes a measurement unit to measure the amount of current supplied
to the portable device through a voltage bus (VBUS), stores a
measurement result in a storage unit, selects, by referring to the
storage unit, an available power indicating circuit exhibiting a
maximum current supply amount, and activates only the selected
available power indicating circuit at a time of actual
operation.
7. The charging method according to claim 6, further comprising
setting, in the power supply unit, a limit value for the amount of
current supplied through the voltage bus (VBUS) in accordance with
an available power indicating circuit to be activated.
8. The charging device according to claim 6, further comprising:
setting one or more limit values for the amount of current supplied
through the voltage bus (VBUS) in accordance with an available
power indicating circuit to be activated at a time of adjustment;
measuring the amount of current to be supplied to the portable
device under respective limit values; storing a measurement result
in the storage unit; selecting an available power indicating
circuit exhibiting the maximum current supply amount and a limit
value for amount of current to be supplied; activating only the
selected available power indicating circuit at a time of actual
operation; and setting, in the power supply unit, the limit value
for the amount of current to be supplied.
9. A method for charging a portable device via a universal serial
bus of a charging device, the method comprising: supplying current
to a portable device coupled through a voltage bus (VBUS);
measuring the amount of current supplied to the portable device
through the voltage bus (VBUS); notifying the portable device
coupled to the charging device of a signal indicating suppliable
amount of current, the notifying being done through a data line by
a plurality of available power indicating circuits, each circuit
having different current supplying ability; at the time of
adjustment, activating through a control unit the available power
indicating circuits one by one, measuring the amount of current
supplied to the portable device, and storing in a storage unit a
measurement result; selecting, by referring to the storage unit, an
available power indicating circuit exhibiting a maximum current
supply amount; and activating only the selected available power
indicating circuit at a time of actual operation, wherein, at the
time of adjustment, the control unit does not obtain from a
portable device information identifying the portable device.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The disclosure of Japanese Patent Application No.
2012-062212 filed on Mar. 19, 2012 including the specification,
drawings and abstract is incorporated herein by reference in its
entirety.
BACKGROUND
[0002] The present invention relates to a charging device, for
example, a charging device which charges a portable device via a
universal serial bus.
[0003] In recent years, charging of portable devices via a USB has
been becoming common. With USB2.0, the maximum current that can be
taken out from a port is defined as 500 mA, and there is a problem
in which it takes a while to charge a high-capacity secondary
battery.
[0004] To address such problems, there is proposed a mechanism
which can determine the power supply ability of the USB charger
(host) side and obtain a current exceeding 500 mA from a charger
having sufficient power supply ability (Japanese Patent No. 4695220
(Patent Document 1), Japanese Patent No. 4664362 (Patent Document
2), U.S. Pat. No. 7,581,119 B2 (Patent Document 3), Japanese Patent
No. 3811704 (Patent Document 4), U.S. Pat. No. 7,170,259 B2 (Patent
Document 5), Japanese Patent Laid-Open No 2005-6497 (Patent
Document 6), and Battery Charging v1.2 Specification, Internet
<URL: http://www.usb.org/developers/devclass_docs>
(Non-Patent Document 1), for example).
SUMMARY
[0005] However, there exist currently various standards, and thus
rapid charging of many portable devices becomes possible only by
dedicated chargers.
[0006] The other problems and new feature will become clear from
the descriptions in the specification and accompanying
drawings.
[0007] A charging device according to an embodiment includes a
plurality of available power indicating circuits which notify,
through a data line, a portable device coupled to the charging
device of a signal indicating suppliable amount of current. A
control unit obtains, from a portable device coupled thereto,
information identifying the portable device, at the time of
adjustment. A storage unit has a table stored therein, for a
plurality of portable devices, defining a correspondence between
information identifying a portable device and an available power
indicating circuit. Referring to the table based on the obtained
information, the control unit selects an available power indicating
circuit and, at the time of actual operation, activates only the
selected available power indicating circuit.
[0008] According to the embodiment described above, a single
charger can rapidly charge portable devices of a plurality of
charging specifications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 shows a configuration of a charger of an
embodiment;
[0010] FIG. 2 shows a configuration of a USB module 10;
[0011] FIG. 3 shows a configuration of an available power
indicating circuit A;
[0012] FIG. 4 shows a configuration of an available power
indicating circuit B;
[0013] FIG. 5 shows a configuration of an available power
indicating circuit C;
[0014] FIGS. 6A and 6B each show an exemplary charger configuration
signal 115 simultaneously transmitted over data lines D+ and
D-;
[0015] FIG. 7 shows an exemplary table;
[0016] FIG. 8 is a flow chart representing an operation procedure
of a first embodiment;
[0017] FIG. 9 is a flow chart representing an operation procedure
of a second embodiment;
[0018] FIG. 10 shows an exemplary determination procedure according
to an exemplary variation of the second embodiment; and
[0019] FIG. 11 shows a flow chart of a third embodiment.
DETAILED DESCRIPTION
[0020] An embodiment of the present invention will be described
below, referring to the drawings.
First Embodiment
[0021] FIG. 1 shows a configuration of a charger of the present
embodiment.
[0022] Referring to FIG. 1, the charger 1 includes a power supply
IC (Integrated Circuit) 2 and an MCU (Micro Control Unit) 3.
[0023] The power supply IC2 supplies current to a portable device
coupled through a voltage bus VBUS.
[0024] The MCU 3 includes a CPU (Central Processing Unit) 4, an ADC
(Analog to Digital Converter) 5, a memory 7, and a USB (Universal
Serial Bus) module 10.
[0025] FIG. 2 shows a configuration of the USB module 10. The USB
module 10 has an SIE (Serial Interface Engine) 11, a transceiver
12, an available power indicating circuit A, an available power
indicating circuit B, an available power indicating circuit C, and
switches SW1A, SW2A, SW1B, SW2B, SW1C, and SW2C.
[0026] The SIE 11 is a logical circuit which processes details of a
low level USB protocol. The transceiver 12 processes the physical
transmission and reception function of the USB.
[0027] The available power indicating circuits A, B, and C notify,
through a data line, a portable device coupled to the charging
device of a signal indicating suppliable amount of current.
[0028] FIG. 3 shows a configuration of the available power
indicating circuit A. Referring to FIG. 3, the available power
indicating circuit A includes resistors 322, 326, and 330. DC PWR
(e.g., 5.0V) is voltage-divided by the resistors 322, 326, and 330.
A voltage VDP which has been voltage-divided from a node 324 is
output to a terminal P1. The terminal P1 is coupled to the data
line D+ via a switch SW1A. A voltage VDM which has been
voltage-divided from a node 328 is output to a terminal P2. The
terminal P2 is coupled to the data line D- via a switch SW2A. By
the voltages VDP and VDM, the portable device coupled thereto
recognizes the current supply ability of a charger 1.
[0029] FIG. 4 shows a configuration of an available power
indicating circuit B. The available power indicating circuit B
corresponds to a Dedicated Charging Port (referred to as DCP, in
the following) in the "Battery Charging Specification" which is the
power supply specifications of the USB. DCP is a port having a
current supply ability of 1.5 A at the maximum.
[0030] As shown in FIG. 4, terminals P3 and P4 are coupled by a
resistor R11 (e.g., a maximum of 200.OMEGA.) between. The portable
device applies a voltage to the data line D+. The available power
indicating circuit B receives a voltage from the terminal P3
coupled to the data line D+. The voltage received by the resistor
R11 is reduced and output from the terminal P4 to the data line D-.
The coupled side of the portable device recognizes the current
supply ability of charger 1, in accordance with the magnitude of
the voltage in the data line D-. That is, the portable device
recognizes that the current supply ability of the charger 1 is 1.5
A, when the magnitude of the voltage over the data line D- is equal
to or larger than a predetermined value. In comparison, the
Standard downstream port (SDP in the following) having a current
supply ability of 500 mA in the "Battery Charging Specification"
has no mechanism of returning the voltage which has been received
from the terminal coupled over the data line D+ to the data line -.
Therefore, the portable device recognizes that the current supply
ability of the charger 1 is 500 mA, when the magnitude of the
voltage over the data line D- is equal to or less than a
predetermined value.
[0031] FIG. 5 shows a configuration of the available power
indicating circuit C. As shown in FIG. 5, the available power
indicating circuit C is equivalent to a signal generator 114
described in Patent Document 6.
[0032] The available power indicating circuit C has a digital timer
310, a switching circuit 312, and RC circuits 314 to 316.
[0033] The available power indicating circuit C operates as
follows. The frequency and the duty cycle of a charger
configuration signal 115 can be adjusted by selecting the values of
resistors and capacitors in the RC circuits 314 to 316.
[0034] The digital timer 310 may be a standard timer IC, for
example. The timer 310 generates a timer output signal 318 which
may be subject to tuning by changing the values of resistors and
capacitors in the RC circuits 314 to 316. The RC circuits 314 to
316 are coupled between the discharge (DIS) input and the threshold
(THR) input of the timer 310.
[0035] The timer output signal 318 is coupled as an input of two
transistor pairs 320 and 322, and 324 and 326 in the switching
circuit 312. The switching circuit 312 adjusts the peak voltage and
impedance output from terminals P5 and P6 to the data lines D+ and
D-.
[0036] FIGS. 6A and 6B each show an exemplary charger configuration
signal 115 simultaneously transmitted over data lines D+ and D-.
FIG. 6A has the charger configuration signal 115 over the data line
D+ plotted along the time axis. FIG. 6B has the charger
configuration signal 115 over the data line D- plotted along the
time axis.
[0037] The charger configuration signal 115 is a periodic digital
signal having a constant frequency (1/T) and a constant duty cycle
(TH/T). The frequency (1/T) and the duty cycle (TH/T) of the
charger configuration signal 115 are set to indicate the current
supply ability of the charger 1. Using the constant frequency (1/T)
and the constant duty cycle (TH/T), the coupled side of the
portable device recognizes the current supply ability of the
charger 1.
[0038] Referring to FIG. 1 again, a memory 6 stores, for a
plurality of portable devices, a table defining the correspondence
between the information identifying a portable device and an
available power indicating circuit and the limit value for the
current supply amount (maximum current supply amount).
[0039] FIG. 7 shows an exemplary table. A vender ID (V_ID) and a
product ID (P_ID) are used as information identifying a portable
device.
[0040] A CPU 4 obtains, from a portable device coupled thereto,
information identifying the portable device when performing
enumeration which is an adjustment stage. Enumeration is a
procedure for identifying a portable device whose host (charger 1)
is coupled to a USB. During enumeration, the portable device
reports its configuration to the host (charger 1). At the time of
recognizing the configuration of the portable device, the host
(charger 1) is allowed to use the portable device.
[0041] Referring to the table based on the obtained information,
the CPU 4 selects an available power indicating circuit and, at the
time of actual operation, activates only the selected available
power indicating circuit, and also turns on only a switch coupled
to the activated available power indicating circuit. In addition,
referring to the table, the CPU 4 sets, in the power supply IC2, a
limit value for the amount of current to be supplied corresponding
to the obtained identification information.
[0042] (Operation)
[0043] FIG. 8 is a flow chart representing an operation procedure
of the first embodiment.
[0044] First, the CPU 4 deactivates all the available power
indicating circuits A, B, and C, and turns off all the switches
SW1A, SW2A, SW1B, SW2B, SW1C, and SW2C coupled to the available
power indicating circuits A, B, and C (step S101).
[0045] Next, the CPU 4 causes the power supply IC2 to supply
current to the portable device through the voltage bus VBUS (step
S102).
[0046] Subsequently, the CPU 4 performs enumeration, detects
existence of coupling of the portable device through the SIE 11,
and obtains information identifying the portable device (vendor ID,
product ID) (step S103).
[0047] When the obtained information identifying the portable
device is not registered in the table (NO at step S104), the
portable device being coupled recognizes the charger 1 as an
ordinary USB module and charges it with 500 mA or lower (step
S105).
[0048] When the obtained information identifying the portable
device is registered in the table (YES at step S104), the CPU 4
causes the power supply IC2 to terminate supply of current through
the voltage bus VBUS (step S106).
[0049] Referring to the table at the time of actual operation, the
CPU 4 activates an available power indicating circuit corresponding
to the obtained identification information, and turns on the switch
coupled to the available power indicating circuit corresponding to
the obtained identification information. In addition, referring to
the table, the CPU 4 sets, in the power supply IC2, a limit value
for the amount of current to be supplied corresponding to the
obtained identification information (step S107).
[0050] Next, the CPU 4 causes the power supply IC2 to supply
current to the portable device through the voltage bus VBUS (step
S108).
[0051] Subsequently, the portable device coupled thereto recognizes
the current supply amount of the charger, in accordance with the
activated available power indicating circuit, and performs charging
(step S109).
[0052] According to the present embodiment, as has been described
above, knowing the type of the portable device coupled thereto
allows activation of an available power indicating circuit suited
to the type, causing the portable device coupled thereto to
recognize the current supply amount of the charger. As a result,
according to the present embodiment, a single charger can support a
plurality of charging specifications, allowing rapid charging of
portable device coupled thereto.
Second Embodiment
[0053] The second embodiment differs from the first embodiment in
the following points.
[0054] The ADC5 measures the amount of current supplied to the
portable device through a voltage bus (VBUS).
[0055] The CPU 4 activates available power indicating circuits one
by one at the time of adjustment, causes the ADC5 to measure the
amount of current supplied to the portable device coupled through
the voltage bus (VBUS), and stores the measurement result in the
memory 6.
[0056] Referring to the memory 6, the CPU 4 selects an available
power indicating circuit exhibiting the maximum current supply
amount and, at the time of actual operation, activates only the
selected available power indicating circuit, and also turns on only
the switch coupled to the activated available power indicating
circuit. In addition, the CPU 4 sets, in the power supply IC2, a
limit value for the amount of current to be supplied corresponding
to the available power indicating circuit to be activated.
[0057] FIG. 9 is a flow chart representing an operation procedure
of the second embodiment. Referring to FIG. 9, the CPU 4 first
activates only the available power indicating circuit A, turns on
the switches SW1A and SW2A coupled to the available power
indicating circuit A, and turns off the remaining switches SW1B,
SW2B, SW1C, and SW2C. The CPU 4 sets, in the power supply IC2, a
limit value for the current supply amount corresponding to the
available power indicating circuit A (corresponding to the standard
A) (step S201).
[0058] Next, the CPU 4 causes the power supply IC2 to supply
current to the portable device through the voltage bus VBUS (step
S202).
[0059] Subsequently, the ADC5 measures, for a certain time period,
the amount of current supplied through the voltage bus VBUS. The
CPU 4 stores, in the memory 6, the maximum amount of current
detected in the ADC5 (step S203).
[0060] Then, the CPU 4 causes the power supply IC2 to terminate
supply of current through the voltage bus VBUS (step S204).
[0061] Next, the CPU 4 activates only the available power
indicating circuit B, turns on the switches SW1B and SW2B coupled
to the available power indicating circuit B, and turns off the
remaining switches SW1A, SW2A, SW1C, and SW2C. The CPU 4 sets, in
the power supply IC2, a limit value for the current supply amount
corresponding to the available power indicating circuit B
(corresponding to the standard B) (step S205).
[0062] Subsequently, the CPU 4 causes the power supply IC2 to
supply current to the portable device through the voltage bus VBUS
(step S206).
[0063] Then, the ADC5 measures, for a certain time period, the
amount of current supplied through the voltage bus VBUS. The CPU 4
stores, in the memory 6, the maximum amount of current detected in
the ADC5 (step S207).
[0064] Subsequently, the CPU 4 causes the power supply IC2 to
terminate supply of current through the voltage bus VBUS (step
S208).
[0065] Then, the CPU 4 activates only the available power
indicating circuit C, turns on the switches SW1C and SW2C coupled
to the available power indicating circuit C, and turns off the
remaining switches SW1A, SW2A, SW1B, and SW2B. The CPU 4 sets, in
the power supply IC2, a limit value for the current supply amount
corresponding to the available power indicating circuit C
(corresponding to the standard C) (step S209).
[0066] Next, the CPU 4 causes the power supply IC2 to supply
current to the portable device through the voltage bus VBUS (step
S210).
[0067] Subsequently, the ADC5 measures, for a certain time period,
the amount of current supplied through the voltage bus VBUS. The
CPU 4 stores, in the memory 6, the maximum amount of current
detected in the ADC5 (step S211).
[0068] Then, the CPU 4 causes the power supply IC2 to terminate
supply of current through the voltage bus VBUS (step S212).
[0069] Next, referring to data stored in the memory, the CPU 4
selects the available power indicating circuit which has supplied
the maximum amount of current (step S213).
[0070] Subsequently, the CPU 4 activates the selected available
power indicating circuit at the time of actual operation, and turns
on the switch coupled to the selected available power indicating
circuit. In addition, the CPU 4 sets, in the power supply IC2, a
limit value for the current supply amount corresponding to selected
available power indicating circuit (step S214).
[0071] Then, the CPU 4 causes the power supply IC2 to supply
current to the portable device through the voltage bus VBUS (step
S215).
[0072] Next, the portable device coupled thereto recognizes the
current supply amount of the charger in accordance with the
activated available power indicating circuit, and performs charging
(step S216).
[0073] According to the present embodiment, as has been described
above, an available power indicating circuit can be selected so
that the current available at the portable device is maximized. As
a result, a single charger can support a plurality of charging
specifications, allowing rapid charging of portable device coupled
thereto. In addition, a limit value for the amount of current to be
supplied from the power supply IC can be set in accordance with the
portable device.
Exemplary Variation of the Second Embodiment
[0074] In this exemplary variation, the CPU 4 sets one or more
limit values for the amount of current to be supplied through the
voltage bus (VBUS), in accordance with the available power
indicating circuit to be activated at the time of adjustment. The
CPU 4 causes the ADC5 to measure, for a certain time period, the
amount of current to be supplied to the portable device through the
voltage bus VBUS under respective limit values, and stores the
maximum value of the measured amount of current in the memory
6.
[0075] Referring to the memory 6, the CPU 4 selects an available
power indicating circuit exhibiting the maximum current supply
amount and a limit value for the amount of current to be supplied,
activates only the selected available power indicating circuit at
the time of actual operation, and sets, in the power supply IC2,
the limit value for the amount of current to be supplied.
[0076] FIG. 10 shows an exemplary determination procedure according
to an exemplary variation of the second embodiment. First, the
available power indicating circuit A is selected, and the limit
value for the current supply amount of the power supply IC2 is set
to 0.5 A. At this time, the maximum value within a certain time
period of the amount of current supplied to the portable device
through the voltage bus VBUS is measured to be 0.1 A. Next, the
limit value for the current supply amount of the power supply IC2
is changed to 0.8 A. At this time, the maximum value within a
certain time period of the amount of current supplied to the
portable device through the voltage bus VBUS is measured to be 0.1
A. Next, the limit value for the current supply amount of the power
supply IC2 is changed to 1.8 A. At this time, the maximum value
within a certain time period of the amount of current supplied to
the portable device through the voltage bus VBUS is measured to be
1.2 A.
[0077] Next, the available power indicating circuit B is selected,
and the limit value for the current supply amount of the power
supply IC2 is set to 1.8 A. At this time, the maximum value within
a certain time period of the amount of current supplied to the
portable device through the voltage bus VBUS is measured to be 0.1
A. Next, the limit value for the current supply amount of the power
supply IC2 is changed to 2.1 A. At this time, the maximum value
within a certain time period of the amount of current supplied to
the portable device through the voltage bus VBUS is measured to be
0.1 A.
[0078] Subsequently, the available power indicating circuit C is
selected, and the limit value for the current supply amount of the
power supply IC2 is set to 1.8 A. At this time, the maximum value
within a certain time period of the amount of current supplied to
the portable device through the voltage bus VBUS is measured to be
0.1 A.
[0079] As a result of the above, in the case where the available
power indicating circuit is A and the limit value for the current
supply amount of the power supply IC2 is 1.8 A, the maximum value
within a certain time period of the amount of current supplied to
the portable device through the voltage bus VBUS is maximized.
Therefore, at the time of actual operation, only the available
power indicating circuit A is activated, and 1.8 A is set, in the
power supply IC, as the limit value for the amount of current
supplied.
Third Embodiment
[0080] The third embodiment is a combination of the selection of an
available power indicating circuit by the first embodiment and the
selection of an available power indicating circuit by the second
embodiment.
[0081] FIG. 11 shows a flow chart of the third embodiment.
Referring to FIG. 11, the CPU 4 first causes the power supply IC2
to supply current to the portable device through the voltage bus
VBUS (step S301).
[0082] Next, the CPU 4 performs enumeration. When there is no
response from the portable device, the process flow proceeds to
step S305.
[0083] When there is a response from the portable device,
information identifying the portable device coupled thereto (vendor
ID, product ID) is obtained. When the obtained identification
information is not registered in the table (No at step S303), the
process flow proceeds to step S305.
[0084] When the obtained identification information is registered
in the table (YEs at step S303), the CPU 4 specifies an available
power indicating circuit corresponding to the obtained
identification information, referring to the table (step S304).
[0085] Next, the CPU 4 causes the power supply IC2 to terminate
supply of current through the voltage bus VBUS (step S318).
[0086] The CPU 4 activates the specified available power indicating
circuit at the time of actual operation, and turns on the switch
coupled to the specified available power indicating circuit. In
addition, referring to the table, the CPU 4 sets, in the power
supply IC2, a limit value for the current supply amount
corresponding to the obtained identification information (step
S319).
[0087] Subsequently, the CPU 4 causes the power supply IC2 to
supply current to a portable device through the voltage bus VBUS
(step S320).
[0088] Next, the portable device coupled thereto recognizes the
current supply amount of the charger in accordance with the
activated available power indicating circuit, and performs charging
(step S321).
[0089] In contrast, when there is no response from the portable
device at step S302 and identification information (vendor ID,
product ID) obtained at step S303 is not registered in the table,
the following process is performed.
[0090] The CPU 4 causes the power supply IC2 to terminate supply of
current through the voltage bus VBUS (step S305).
[0091] Next, the CPU 4 activates only the available power
indicating circuit A, turns on the switches SW1A and SW2A coupled
to the available power indicating circuit A, and turns off the
remaining switches SW1B, SW2B, SW1C, and SW2C. The CPU 4 sets, in
the power supply IC2, a limit value for the current supply amount
corresponding to the available power indicating circuit A (step
S306).
[0092] Subsequently, the CPU 4 causes the power supply IC2 to
supply current to the portable device through the voltage bus VBUS
(step S307).
[0093] Next, the ADC5 measures, for a certain time period, the
amount of current supplied through the voltage bus VBUS. The CPU 4
stores, in the memory 6, the maximum amount of current detected in
the ADC5 (step S308).
[0094] Subsequently, the CPU 4 causes the power supply IC2 to
terminate supply of current through the voltage bus VBUS (step
S309).
[0095] Then, the CPU 4 activates only the available power
indicating circuit B, turns on the switches SW1B and SW2B coupled
to the available power indicating circuit B, and turns off the
remaining switches SW1A, SW2A, SW1C, and SW2C. The CPU 4 sets, in
the power supply IC2, the maximum amount of current corresponding
to the available power indicating circuit B (step S310).
[0096] Next, the CPU 4 causes the power supply IC2 to supply
current to the portable device through the voltage bus VBUS (step
S311).
[0097] Subsequently, the ADC5 measures, for a certain time period,
the amount of current supplied through the voltage bus VBUS. The
CPU 4 stores, in the memory 6, the maximum amount of current
detected in the ADC5 (step S312).
[0098] Then, the CPU 4 causes the power supply IC2 to terminate
supply of current through the voltage bus VBUS (step S313).
[0099] Subsequently, the CPU 4 activates only the available power
indicating circuit C, turns on the switches SW1C and SW2C coupled
to the available power indicating circuit C, and turns off the
remaining switches SW1A, SW2A, SW1B, and SW2B. The CPU 4 sets, in
the power supply IC2, the maximum of the current supply amount
corresponding to the available power indicating circuit C (step
S314).
[0100] Next, the CPU 4 causes the power supply IC2 to supply
current to the portable device through the voltage bus VBUS (step
S315).
[0101] Then, the ADC5 measures, for a certain time period, the
amount of current supplied through the voltage bus VBUS. The CPU 4
stores, in the memory 6, the maximum amount of current detected in
the ADC5 (step S316).
[0102] Next, referring to data stored in the memory, the CPU 4
selects the available power indicating circuit which has supplied
the maximum amount of current (step S317).
[0103] Subsequently, the CPU 4 causes the power supply IC2 to
terminate supply of current through the voltage bus VBUS (step
S318).
[0104] Then, the CPU 4 activates the selected available power
indicating circuit at the time of actual operation, and turns on
the switch coupled to the selected available power indicating
circuit. In addition, the CPU 4 sets, as the current limit value of
the power supply IC2, the amount of maximum current of the selected
available power indicating circuit (step S319).
[0105] Next, the CPU 4 causes the power supply IC2 to supply
current to the portable device through the voltage bus VBUS (step
S320).
[0106] Subsequently, the portable device coupled thereto recognizes
the current supply amount of the charger in accordance with the
activated available power indicating circuit, and performs charging
(step S321).
[0107] According to the present embodiment, as has been described
above, an available power indicating circuit can be selected using
identification information when the identification information from
the portable device is available, and an available power indicating
circuit can be selected so that current available in the portable
device side is maximized when identification information from the
portable device is not available. As a result, a single charger can
support a plurality of charging specifications, allowing rapid
charging of portable device coupled thereto.
[0108] Although the invention made by the inventors has been
specifically described above based on embodiments, it is needless
to say that the present invention is not limited to the embodiments
and various modifications are possible within a scope not departing
from the gist of the invention.
* * * * *
References