(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2003/0030412 A1
`Matsuda et al.
`(43) Pub. Date: Feb. 13, 2003
`
`
`US 20030030412A1
`
`(54) POWER CONTROL CIRCUIT, ELECTRONIC
`INSTRUMENT, AND CHARGING METHOD
`
`(52) us. Cl.
`
`.............................................................. 320/127
`
`(75)
`
`Inventors: Kuniaki Matsuda, Sapporo-shi (JP);
`Shun Oshita, Sapporo-shi (JP)
`
`Correspondence Address:
`OLIFF & BERRIDGE, PLC
`P.O. BOX 19928
`ALEXANDRIA, VA 22320 (US)
`
`(73) Assignee:
`
`SEIKO EPSON CORPORATION,
`Tokyo (JP)
`
`(21) Appl. No.:
`
`10/201,779
`
`(22)
`
`Filed:
`
`Jul. 25, 2002
`
`(30)
`
`Foreign Application Priority Data
`
`Aug. 10, 2001
`
`(JP) ...................................... 2001-243535
`
`Publication Classification
`
`(51)
`
`Int. Cl.7 ........................................................ H02J 7/00
`
`(57)
`
`ABSTRACT
`
`When an electronic instrument Q is in normal operating
`mode and set to be slave, power from a rechargeable battery
`or an external power source is supplied to a data transfer
`control circuit, and when the electronic instrument Q is in
`charge mode and set to be slave, power from VBUS is
`supplied thereto to charge a rechargeable battery. When an
`external power source can be used in charge mode, power
`from the external power source is supplied to the recharge-
`able battery instead of from VBUS. When an electronic
`instrument P is in normal operating mode and set to be
`master, power from a rechargeable battery or an external
`power source is supplied to the data transfer control circuit
`and the electronic instrument Q; and when the electronic
`instrument P is in charge mode and set to be master, power
`from the rechargeable battery or the external power source
`is supplied to the electronic instrument Q through the VBUS
`in order to charge a rechargeable battery of the electronic
`instrument Q. In charge mode, the supply of power to the
`data transfer control circuit is either turned off or an energy-
`saving mode is set.
`
`ID DE-
`TECTION
`
`ID DE-
`
`
`
`
`
`
`
`SWITCHOVER
`
`
`TICCURRENT
`POW-ER
`LIMITAU
`
`SOURCE i. Tum
`20HI. SELECTOR
`
`1 g
`POWER-
`
`SUPPLY
`
`SWITCHING
`CHARGE
`
`LEVEL
`
`
`DETECTION
`
`
`VOLTAGE
`
`LEVEL
`
`
`DETECTION
`
`ELECTRONIC EQUIPMENT 0 (SLAVE SIDE)
`ELECTRONIC EQUIPMENT P (MASTER SIDE)
`CMODE
`CMODE
`
`
`
`3O
`
`POWER
`
`POWER
`
`
`
`CONTROL
`
`CONTROL
`
`
`
`
`
`TECTION Flt—-
`
`CURRENT '-
`
`
`
`
`UM'TAU '
`POWER
`“0” I
`SOURCE
`
`
`40 SELECTOR
`sWITCHOVER
`
`
`POWER—
`
`
`SUPPLY
`
`SWITCHING
`CHARGE
`
`
`
`LEVEL
`DETECTION
`
`
`VOLTAGE
`LEVEL
`
`DETECTION
`
`
`4
`
`
`DATA
`
`
`TRANSFER
`TRANSFER
`RECHARGEABLE
`
`DATA
`E
`
`
`
`BATTERY
`CONTROL (use -”E=- CONTROL (USB
`;
`
`
`
`PROCESSING) PROCESSING)
`
`0'
`
`EXTERNAL
`POWER
`SOURCE
`
`
`
`
`RECHARGEABLE
`BATTERY
`
`EXTERNAL
`
`
`POWER
`SOURCE
`
`
`
`Apple Inc. v. Qualcomm Incorporated
`IPR2018-01283
`
`Qualcomm Ex. 2004
`
`Page 1 of 25
`
`Apple Inc. v. Qualcomm Incorporated
`IPR2018-01283
`Qualcomm Ex. 2004
`Page 1 of 25
`
`

`

`Patent Application Publication
`
`Feb. 13, 2003 Sheet 1 0f 12
`
`US 2003/0030412 A1
`
`FICE-‘I/\
`
`MASTER
`
`
`
`
`
`7
`
`
`
`u_% 4*" J
`ELEZ
`ELLW
`DESKTOPPC
`
`USB
`CABLE
`
`@
`CE
`
`OUTLET
`
`FIG.
`
`1 B
`
`SLAVE
`:bHARGmG
`
`
`
`2:93:33.»
`Egg
`MOBu
`
`PHONE
`
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`MOBmE
`PHONE
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`'m#
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`x
`
`_._____--__.______- ______
`DIGITAL CAMERA
`
`,
`
`Page 2 Of 25
`
`lIIIlIIIIIIIl|| IIII||IIIIII IIIIIIIIIIIIIIIlIIIIlII IIIIIIIIII|| IIIIIIIIIIIIIIIIIII IIIIIIIIIlII IllIlI
`
`
`
`
`
`
`
`NOTEBOOK PC
`
`OUTLE
`
`FHCE. 1(3
`
`PORTABLE AUDIO PLAYER
`
`Page 2 of 25
`
`

`

`Patent Application Publication
`
`Feb. 13, 2003 Sheet 2 0f 12
`
`US 2003/0030412 A1
`
`FIG. 2A
`
`A PLUG
`
`B PLUG
`
`
`
`FIG. 2B
`
`FIG. 2C
`
`GND
`
`D- (DATA LINE)
`
`
`
`
`D+ (DATA LINE)
`
`
`
`USB CABLE
`
`- ELECTRONIC
`. EQUIPMENT Q
`
`ELECTRONIC
`EQUIPMENT P
`
`‘
`
`MASTER
`
`SLAVE
`
`FIG. 2D
`
`EQUIPMENT Q
`
`ELECTRONIC
`EQUIPMENT P
`
`USB CABLE
`
`ELECTRONIC
`
`SLAVE
`
`MASTER
`
`Page 3 of 25
`
`Page 3 of 25
`
`

`

`Patent Application Publication
`
`Feb. 13, 2003 Sheet 3 0f 12
`
`US 2003/0030412 A1
`
`FIG. 3A
`
`ELECTRONIC
`ELECTRONIC
`‘ PLUG U33 CABLE B PLUG EQUIPMENT 0
`EQUIPMENT P
`100 -—-————
`102
`
`
`
`BATTERY
`
`CHARGING
`
`BATTERY
`
`MASTER
`
`SLAVE
`
`FIG. 3B
`
`
`
`ELECTRONIC
` ELECTRONIC
`EQUIPMENTP BPLUG U33 CABLE APLUG EOUIPMENTQ
`
`
`, 100
`-————I
`102
`RECHARGEABLE _ RECHARGEABLE
`
`
`CHARGING
`BATTERY
`BATTERY
`
`
`SLAVE
`
`MASTER
`
`Page 4 Of 25
`
`Page 4 of 25
`
`

`

`Patent Application Publication
`
`Feb. 13, 2003 Sheet 4 0f 12
`
`US 2003/0030412 A1
`
` mOmDOwmomDOw
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`
`Page 5 0f25
`
`Page 5 of 25
`
`

`

`Patent Application Publication
`
`Feb. 13, 2003 Sheet 5 0f 12
`
`US 2003/0030412 A1
`
`FIG. 5A
`
`ELECTRONIC EQUIPMENT P
`
`USB CABLE
`
`LOW MSSEL
`LEVEL
`
`MASTER
`
`"""
`
`
`
`FIG. SB
`
`( SOCKET
`receptacle)
`
`ELECTRONIC EQUIPMENT 0
`
`USB CABLE
`
`HIGH MSSEL
`LEVEL
`
`SLAVE
`
`"""
`
`
`
`
`FIG. 5C
`
`( SOCKET
`receptacle)
`
`Page 6 of 25
`
`Page 6 of 25
`
`

`

`Patent Application Publication
`
`Feb. 13, 2003 Sheet 6 0f 12
`
`US 2003/0030412 A1
`
`FIG. 6
`
`START
`
`S1
`
`
`
`MASTER OR SLAVE?
`
`MASTER
`
`
`
`
`
`(MSSEL?)
`
`
`32
`NORMAL
`33
`NORMAL
`
`NORMAL
`OPERATING
`NORMAL
`OPERATING
`
`
`OPERATING MODE OR
`MODE
`OPERATING MODE OR
`MODE
`
`
`
`
`
`CHARGE MODE?
` CHARGE MODE?
`
`
`(CMODE?)
`(CMODE?)
`
`
`CHARGE
`CHARGE
`
`MODE
`MODE
`
`
`
`Page 7 of 25
`
`Page 7 of 25
`
`

`

`Patent Application Publication
`
`Feb. 13, 2003 Sheet 7 0f 12
`
`US 2003/0030412 A1
`
`FIG- 7
`
`S1 1
`
`SLAVE AND NORMAL
`
`OPERATING MODE
`
`
`
`TURN ON POWER SUPPLY
`
`
`TO DATA TRANSFER
`CONTROL CIRCUIT
`
`
`
`
`
`SELECT VBUS-SIDE PATH
`BY SELECTOR
`
`
`
`
` CAN EXTERNAL
`
`POWER SOURCE BE USED?
`(VLDET‘?)
`
`SUPPLY POWER FROM USE VBUS
`SUPPLY POWER FROM USE VBUS
`
`
`
`LINE OR EXTERNAL POWER
`LINE OR RECHARGEABLE
`
`
`
`SOURCE TO DATA TRANSFER
`BATTERY (SLAVE SIDE) TO DATA
`
`
`
`CONTROL CIRCUIT, THROUGH
`' TRANSFER CONTROL CIRCUIT,
`
`
`
`POWER SOURCE SWITCHOVER
`THROUGH POWER SOURCE
`
`
`
`CIRCUIT
`SWITCHOVER CIRCUIT
`
`
`
`SUPPLY POWER FROM EXTERNAL
`POWER SOURCE TO
`RECHARGEABLE BATTERY
`
`(SLAVE SIDE), THROUGH POWER
`
`SOURCE SWITCHOVER CIRCUIT
`
`817
`CHARGE RECHARGEABLE
`
`
`
`BATTERY (SLAVE SIDE)
`
`
`[S1 8
`
`
`LEVEL AT EEAAE'PLT?HIGH AS
`
`
`THRESHOLD LEVEL?
`
`THE SLAVE-
`SIDE EXTERNAL
`POWER SOURCE
`IS USED TO
`CHARGE THE
`
`SLAVE-SIDE
`RECHARGEABLE
`BATTERY
`
`
`
`HALT SUPPLY OF POWER TO
`RECHARGEABLE BATTERY
`
` S19
`
`Page 8 of 25
`
`Page 8 of 25
`
`

`

`Patent Application Publication
`
`Feb. 13, 2003 Sheet 8 0f 12
`
`US 2003/0030412 A1
`
`FIG. 8
`
`
`
`
`
`
`
`e SLAVE AND CHARGE MODE
`
`
`821
`
`
`
`TURN OFF POWER SUPPLY
`TO DATA TRANSFER
`CONTROL CIRCUIT
`
`
`822
`
`
`
`SELECT PATH ON CURRENT
`LIMITATION CIRCUIT SIDE
`BY SELECTOR
`
`
`
`
`823
`
`CAN EXTERNAL
`
`POWER SOURCE BE USED?
`
`(VLDET?)
`
`
`
`
`
`
`
`
`
`
`SUPPLY POWER FROM EXTERNAL
`SUPPLY POWER FROM USE VBUS
`
`POWER SOURCE TO
`LINE T0 RECHARGEABLE
`
`RECHARGEABLE BATTERY
`BATTERY (SLAVE SIDE)
`
`THROUGH POWER SOURCE
`(SLAVE SIDE) THROUGH POWER
`
`SOURCE SWITCHOVER CIRCUIT
`SWITCHOVER CIRCUIT
`
`
`
`
`
`
`
`
`
`826
`CHARGE RECHARGEABLE
`
`BATTERY (SLAVE SIDE)
`
`
`827
`IS CHARGING
`
`
`LEVEL AT LEAST AS HIGH AS
`THRESHOLD LEVEL?
`
`
`
`HALT SUPPLY OF POWER TO
`RECHARGEABLE BATTERY
`
`
`
`
`
`THE VBUS LINE OR
`SLAVE-SIDE EXTERNAL
`POWER SOURCE IS USED
`TO CHARGE THE SLAVE-
`SIDE RECHARGEABLE
`BATTERY
`'
`
`Page 9 of 25
`
`Page 9 of 25
`
`

`

`Patent Application Publication
`
`Feb. 13, 2003 Sheet 9 0f 12
`
`US 2003/0030412 A1
`
`FIG. 9
`
`6 MASTER AND NORMAL OPERATING MODE
`
`
`
`TURN ON POWER SUPPLY
`TO DATA TRANSFER
`CONTROL CIRCUIT
`
`CAN EXTERNAL
`
`POWER SOURCE BE USED?
`
`(VLDET?)
`
`
`
`
`
`
`
`SUPPLY POWER FROM
`
`RECHARGEABLE BATTERY (MASTER
`
`
`SIDE) TO USE VBUS LINE AND DATA
`
`TRANSFER CONTROL CIRCUIT.
`
`
`THROUGH POWER SOURCE
`
`
`SWITCHOVER CIRCUIT
`
`SUPPLY POWER FROM
`EXTERNAL POWER SOURCE TO
`USE VBUS LINE AND DATA
`TRANSFER CONTROL CIRCUIT,
`THROUGH POWER SOURCE
`SWITCHOVER CIRCUIT
`
`
`
`
`SUPPLY POWER FROM EXTERNAL
`POWER SOURCE T0
`RECHARGEABLE BATTERY (MASTER
`SIDE) THROUGH POWER SOURCE
`SWITCHOVER CIRCUIT
`
`CHARGE RECHARGEABLE
`
`BATTERY (MASTER SIDE)
`
`
`
`
`S37
`IS CHARGING
`
`LEVEL AT LEAST AS HIGH AS
`THRESHOLD LEVEL?
`
` S38
`
`HALT SUPPLY OF POWER TO
`RECHARGEABLE BATTERY
`
`
`
`
`
`THE MASTER—
`
`SIDE EXTERNAL
`POWER SOURCE
`IS USED TO
`CHARGE THE
`
`MASTER—SIDE
`RECHARGEABLE
`BATTE RY
`
`Page 10 of 25
`
`Page 10 of 25
`
`

`

`Patent Application Publication
`
`Feb. 13, 2003 Sheet 10 0f 12
`
`US 2003/0030412 A1
`
`FIG. 10
`
`
`
`0 MASTER AND CHARGE MODE
`
`S41
`
`TURN OFF POWER SUPPLY
`TO DATA TRANSFER
`CONTROL CIRCUIT
`
`
`
`
`
`
`S42
`CAN EXTERNAL
`
`POWER SOURCE BE USED?
`
`(VLDET?)
`
`SUPPLY POWER FROM ‘
`SUPPLY POWER FROM EXTERNAL
`
`
`RECHARGEABLE BATTERY
`
`(MASTER SIDE) TO USE VBUS
`POWER SOURCE To “$3 VBUS
`LINE. THROUGH POWER SOURCE
`UNE- THROUGH POWER SOURCE
`
`SWITCHOVER CIRCUIT
`SWITCHOVER CIRCUIT
`
`SUPPLY POWER FROM EXTERNAL
`
`POWER SOURCE TO
`RECHARGEABLE BATTERY
`(MASTER SIDE) THROUGH POWER
`
`SOURCE SWITCHOVER CIRCUIT
`
`CHARGE RECHARGEABLE
`
`BATTERY (MASTER SIDE)
`
`
`
`
`IS CHARGING
`
`LEVEL AT LEAST AS HIGH AS
`THRESHOLD LEVEL?
`
` S48
`
`HALT SUPPLY OF POWER TO
`RECHARGEABLE BATTERY
`
`THE MASTER-
`SIDE EXTERNAL
`POWER SOURCE
`IS USED TO
`CHARGE THE
`MASTER-SIDE
`RECHARGEABLE
`BATTERY
`
`Page 11 Of 25
`
`Page 11 of 25
`
`

`

`Patent Application Publication
`
`Feb. 13, 2003 Sheet 11 0f 12
`
`US 2003/0030412 A1
`
`FIG. 11
`
`54
`
`52
`
`
`
`
`END-POINT
`
`BUFFER
`
`
`
`GENERATION
`
`
`OSCILLATION
`
`DATA TRANSFER CONTROL (USB PROCESSING) CIRCUIT
`
`57
`
`58
`
`Page 12 of 25
`
`Page 12 of 25
`
`

`

`Patent Application Publication
`
`Feb. 13, 2003 Sheet 12 0f 12
`
`US 2003/0030412 A1
`
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`Page 13 0f25
`
`Page 13 of 25
`
`
`
`
`
`
`

`

`US 2003/0030412 A1
`
`Feb. 13, 2003
`
`POWER CONTROL CIRCUIT, ELECTRONIC
`INSTRUMENT, AND CHARGING METHOD
`
`Japanese patent application no. 2001-243535 filed
`[0001]
`on Aug. 10, 2001 is hereby incorporated by reference in its
`entirety.
`
`BACKGROUND
`
`[0002] The present invention relates to a power control
`circuit, an electronic instrument, and a charging method.
`
`It is usual for a portable electronic instrument such
`[0003]
`as mobile phones to be battery-powered, and it is necessary
`to provide a dedicated AC adapter or charger for charging a
`rechargeable battery (a chargeable storage battery, or sec-
`ondary battery) thereof. It often happens that such an AC
`adapter or charger cannot be used in a portable electronic
`instrument of different types (made by the same manufac-
`turer or another manufacturer) . For that reason, when the
`possessor of a plurality of portable electronic instruments
`goes out, it is necessary to carry a number of AC adapters or
`chargers, which is inconvenient.
`
`[0004] Recently, the universal serial bus (USB) standard
`has suddenly permeated the marketplace, as an interface
`standard for connecting a personal computer (hereinafter
`called “PC”) to its peripherals. This USB standard has the
`advantage of enabling the use of connectors of the same
`standard to connect a peripheral instrument such as a mouse,
`keyboard, and printer, which are connected by connectors of
`different standards in the prior art, and of making it possible
`to implement plug-and-play and hot-plug features.
`
`In addition to data lines (D+ and D—), a USB cable
`[0005]
`has power lines (VBUS and GND) . Use of these power lines
`in the USB cable makes it possible to charge a portable
`electronic instrument such as mobile phones, and techniques
`disclosed in Japanese Patent Application Laid-Open Nos.
`2000-339067 and 2000-201204 are known as prior-art tech-
`niques relating to such a charging method.
`
`techniques necessitate
`these prior-art
`[0006] However,
`dedicated connectors and control circuits for connecting the
`USB cable to a portable electronic instrument such as a
`mobile phone, so that a general-purpose USB cable alone
`cannot be used for connecting a PC and the portable elec-
`tronic instrument.
`
`In addition, these prior-art techniques dictate that
`[0007]
`the side that supplies power for charging a rechargeable
`battery (the source of the power for charging) is fixed as the
`PC acting as host, and the side that charges the rechargeable
`battery with the power supplied from the charging power is
`fixed as the portable electronic instrument that is the device
`(function or target) . It is therefore not possible to set an
`electronic instrument to be either the source that supplies the
`charging power or the destination of that charging power. A
`problem arises in that a PC which is a host must always be
`used when using a USB cable to charge a rechargeable
`battery of a portable electronic instrument.
`
`SUMMARY
`
`[0008] One aspect of the present invention relates to a
`power control circuit used in an electronic instrument that is
`provided with a universal serial bus (USB) interface,
`
`[0009] wherein when the electronic instrument has been
`set to a slave side for USB data transfer and has been set to
`
`normal operating mode, the power control circuit supplies
`power from a USB power line, power from a rechargeable
`battery, or power from an external power source to a data
`transfer control circuit which controls USB data transfer;
`and
`
`[0010] wherein when the electronic instrument has been
`set to the slave side for USB data transfer and has been set
`
`to charge mode, the power control circuit supplies power
`from the USB power line to the rechargeable battery of the
`electronic instrument in order to charge the rechargeable
`battery.
`
`[0011] Another aspect of the present invention relates to a
`power control circuit used in an electronic instrument that is
`provided with a universal serial bus (USB) interface,
`
`[0012] wherein when the electronic instrument has been
`set to a master side for USB data transfer and has been set
`
`to normal operating mode, the power control circuit supplies
`power from a rechargeable battery or power from an external
`power source to a data transfer control circuit which controls
`USB data transfer; and
`
`[0013] wherein when the electronic instrument has been
`set to the master side for USB data transfer and has been set
`
`to charge mode, the power control circuit supplies power
`from the rechargeable battery or power from the external
`power source to another electronic instrument on a slave
`side through a USB power line,
`in order to charge a
`rechargeable battery of the other electronic instrument on
`the slave side connected to the electronic instrument by
`USB.
`
`[0014] A further aspect of the present invention relates to
`a power control circuit used in an electronic instrument that
`is provided with a universal serial bus (USB) interface,
`
`[0015] wherein when the electronic instrument has been
`set to a slave side for USB data transfer and has been set to
`
`normal operating mode, the power control circuit supplies
`power from a USB power line, power from a rechargeable
`battery, or power from an external power source to a data
`transfer control circuit which controls USB data transfer;
`
`[0016] wherein when the electronic instrument has been
`set to the slave side for USB data transfer and has been set
`
`to charge mode, the power control circuit supplies power
`from the USB power line to the rechargeable battery of the
`electronic instrument in order to charge the rechargeable
`battery;
`
`[0017] wherein when the electronic instrument has been
`set to a master side for USB data transfer and has been set
`
`to normal operating mode, the power control circuit supplies
`power from the rechargeable battery or power from the
`external power source to the data transfer control circuit
`which controls USB data transfer; and
`
`[0018] wherein when the electronic instrument has been
`set to the master side for USB data transfer and has been set
`
`to charge mode, the power control circuit supplies power
`from the rechargeable battery or power from the external
`power source to another electronic instrument on the slave
`side through the USB power line,
`in order to charge a
`rechargeable battery of the other electronic instrument on
`the slave side connected to the electronic instrument by
`USB.
`
`Page 14 of 25
`
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`

`

`US 2003/0030412 A1
`
`Feb. 13, 2003
`
`BRIEF DESCRIPTION OF THE SEVERAL
`VIEWS OF THE DRAWING
`
`[0019] FIGS. 1A, 1B, and 1C are illustrative of the
`charging method of this embodiment;
`
`[0020] FIGS. 2A, 2B, 2C, and 2D are illustrative of USB
`cables and plugs;
`
`[0021] FIGS. 3A and 3B are illustrative of the charging
`method of this embodiment;
`
`[0022] FIG. 4 is illustrative of an example of the configu-
`ration of the power control circuit and electronic instrument
`of this embodiment;
`
`[0023] FIGS. 5A, 5B, and 5C are illustrative of the
`method of setting master and slave and the method of setting
`charge mode or normal operating mode;
`
`[0024] FIG. 6 is a flowchart illustrating the operation of
`this embodiment;
`
`[0025] FIG. 7 is a flowchart illustrating the operation of
`this embodiment for an electronic instrument set to be slave
`
`and set to normal operating mode;
`
`[0026] FIG. 8 is a flowchart illustrating the operation of
`this embodiment for an electronic instrument set to be slave
`
`and set to charge mode;
`
`[0027] FIG. 9 is a flowchart illustrating the operation of
`this embodiment for an electronic instrument set
`to be
`
`master and set to normal operating mode;
`
`from the USB power line to the rechargeable battery of the
`electronic instrument in order to charge the rechargeable
`battery.
`
`[0035] With this embodiment, in normal operating mode,
`the data transfer control circuit (slave side) operates with
`power supplied from a USB power line, rechargeable battery
`(slave side), or external power source (slave side) . In charge
`mode, on the other hand, power is supplied to the recharge-
`able battery (slave side) from the USB power line (electronic
`instrument on the master side), and the rechargeable battery
`is charged thereby.
`
`[0036] The thus-configured embodiment of the present
`invention makes it possible to use a general-purpose USB
`cable to charge a rechargeable battery in an electronic
`instrument on the slave side, by way of example. If the user
`is in a situation in which there is no host available, it is
`possible to charge the rechargeable battery of the electronic
`instrument on the slave side by power from other electronic
`instrument on the master side. This enables an improvement
`in convenience to the user.
`
`[0037] With this power control circuit, when the external
`power source is usable in charge mode, the power control
`circuit may supply power from the external power source to
`the rechargeable battery.
`
`[0038] This makes it possible to use an external power
`source (slave side) with a high power supply capability,
`enabling efficient charging of the rechargeable battery of the
`slave-side electronic instrument.
`
`[0028] FIG. 10 is a flowchart illustrating the operation of
`this embodiment for an electronic instrument set
`to be
`
`[0039] The power control circuit may further comprise
`current limitation circuit which restricts a maximum current
`
`master and set to charge mode;
`
`of power from the USB power line in charge mode.
`
`[0029] FIG. 11 shows an example of the configuration of
`the data transfer control circuit; and
`
`[0030] FIG. 12 is illustrative of an example of the con-
`figuration of a power control circuit and an electronic
`instrument in accordance with another embodiment of the
`
`present invention.
`
`DETAILED DESCRIPTION
`
`[0031] Embodiments of
`described in detail below.
`
`the
`
`present
`
`invention
`
`are
`
`[0032] Note that the embodiments described hereunder do
`not in any way limit the scope of the invention defined by the
`claims laid out herein. Note also that all of the elements of
`
`these embodiments should not be taken as essential require-
`ments to the means of the present invention.
`
`[0033] One embodiment of the present invention relates to
`a power control circuit used in an electronic instrument that
`is provided with a universal serial bus (USB) interface,
`wherein when the electronic instrument has been set to a
`slave side for USB data transfer and has been set to normal
`
`operating mode, the power control circuit supplies power
`from a USB power line, power from a rechargeable battery,
`or power from an external power source to a data transfer
`control circuit which controls USB data transfer; and
`
`[0034] wherein when the electronic instrument has been
`set to the slave side for USB data transfer and has been set
`
`to charge mode, the power control circuit supplies power
`
`[0040] This makes it possible to prevent the flow of a large
`current in the USB power line in charge mode, enhancing the
`reliability.
`
`invention
`[0041] Another embodiment of the present
`relates to a power control circuit used in an electronic
`instrument that is provided with a universal serial bus (USB)
`interface,
`
`[0042] wherein when the electronic instrument has been
`set to a master side for USB data transfer and has been set
`
`to normal operating mode, the power control circuit supplies
`power from a rechargeable battery or power from an external
`power source to a data transfer control circuit which controls
`USB data transfer; and
`
`[0043] wherein when the electronic instrument has been
`set to the master side for USB data transfer and has been set
`
`to charge mode, the power control circuit supplies power
`from the rechargeable battery or power from the external
`power source to another electronic instrument on a slave
`side through a USB power line,
`in order to charge a
`rechargeable battery of the other electronic instrument on
`the slave side connected to the electronic instrument by
`USB.
`
`[0044] This embodiment enables the supply of power from
`a rechargeable battery (master side) or external power
`source (master side) when in normal operating mode, for the
`operation of the data transfer control circuit (master side) .
`In charge mode, on the other hand, power from the recharge-
`able battery (master side) or external power source (master
`
`Page 15 of25
`
`Page 15 of 25
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`

`

`US 2003/0030412 A1
`
`Feb. 13, 2003
`
`to charge a
`is supplied to the USB power line,
`side)
`rechargeable battery of an electronic instrument on the slave
`side, which is connected to this USB power line.
`
`[0045] The thus-configured embodiment of the present
`invention makes it possible to use a general-purpose USB
`cable to charge a rechargeable battery in an electronic
`instrument on the slave side, by way of example. If the user
`is in a situation in which there is no host available, it is
`possible to charge the rechargeable battery of the electronic
`instrument on the slave side by power from other electronic
`instrument on the master side. This enables an improvement
`in convenience to the user.
`
`[0046] With this power control circuit, when the external
`power source is usable in charge mode, the power control
`circuit may supply power from the external power source to
`the other electronic instrument on the slave side through the
`USB power line.
`
`[0047] This makes it possible to use an external power
`source (master side) with a high power supply capability,
`enabling efficient charging of the rechargeable battery of the
`slave-side electronic instrument.
`
`invention
`[0048] A further embodiment of the present
`relates to a power control circuit used in an electronic
`instrument that is provided with a universal serial bus (USB)
`interface,
`
`[0049] wherein when the electronic instrument has been
`set to a slave side for USB data transfer and has been set to
`
`normal operating mode, the power control circuit supplies
`power from a USB power line, power from a rechargeable
`battery, or power from an external power source to a data
`transfer control circuit which controls USB data transfer;
`
`[0050] wherein when the electronic instrument has been
`set to the slave side for USB data transfer and has been set
`
`to charge mode, the power control circuit supplies power
`from the USB power line to the rechargeable battery of the
`electronic instrument in order to charge the rechargeable
`battery;
`
`[0051] wherein when the electronic instrument has been
`set to a master side for USB data transfer and has been set
`
`to normal operating mode, the power control circuit supplies
`power from the rechargeable battery or power from the
`external power source to the data transfer control circuit
`which controls USB data transfer; and
`
`[0052] wherein when the electronic instrument has been
`set to the master side for USB data transfer and has been set
`
`to charge mode, power from the rechargeable battery or
`power from the external the power control circuit supplies
`power source to another electronic instrument on the slave
`side through the USB power line,
`in order to charge a
`rechargeable battery of the other electronic instrument on
`the slave side connected to the electronic instrument by
`USB.
`
`[0053] This embodiment makes it possible to impart
`power control functions to an electronic instrument on both
`the master side and the slave side. If the charge of the battery
`in an electronic instrument should drop, the rechargeable
`battery within that an electronic instrument can be charged
`by setting that an electronic instrument to be the slave and
`connecting it by a USB cable to another electronic instru-
`ment. Similarly, if the charge of the battery in the other
`
`electronic instrument should drop, the rechargeable battery
`within the other electronic instrument can be charged by
`setting the electronic instrument to be the master and con-
`necting it by a USB cable to the other electronic instrument.
`This makes it possible to implement an extremely conve-
`nient charging method.
`
`[0054] With this power control circuit, in charge mode,
`supply of power to the data transfer control circuit may be
`turned off or the data transfer control circuit is set to an
`
`energy-saving mode.
`
`[0055] This makes it possible to prevent wasteful con-
`sumption of power by the data transfer control circuit when
`in charge mode, facilitating a reduction in the energy con-
`sumption of the electronic instrument.
`
`[0056] With this power control circuit, when a first plug of
`a USB cable is connected to the electronic instrument, the
`power control circuit may determine that
`the electronic
`instrument is set to a master side, and when a second plug
`of the USB cable has been connected to the electronic
`
`instrument, the power control circuit may determine that the
`electronic instrument is set to the slave side,
`to select a
`power control function linked thereto.
`
`[0057] This makes it possible to freely set an electronic
`instrument to either the master side or the slave side, simply
`by changing the way in which the USB cable is connected.
`It is possible to set an electronic instrument to the master
`side and supply power to an electronic instrument on the
`slave side, to charge a rechargeable battery of the electronic
`instrument on the slave side, or set an electronic instrument
`to the slave side and receive power from an electronic
`instrument on the master side, to charge the rechargeable
`battery of the electronic instrument.
`
`[0058] With this power control circuit, each of the first and
`second plugs of the USB cable may have an identification
`terminal for identifying the master side or the slave side; and
`
`the power control circuit may determine whether
`[0059]
`the electronic instrument has been set to the master side or
`
`the slave side, by detecting a voltage level of the identifi-
`cation terminal when the electronic instrument is connected
`
`to one of the first and second plugs of the USB cable.
`
`[0060] This makes it possible to determine whether an
`electronic instrument has been set to the master side or the
`
`slave side, by simple processing that merely detects the
`voltage level of the identification terminal.
`
`[0061] Note that the circuit that detects the voltage level of
`the identification terminal could be conceived as a circuit
`
`comprising a resistor with one end connected to a first power
`source (such as a high-potential side of a power source, or
`VDD) and the other end connected to the identification
`terminal. It is desirable that the identification terminal is
`
`connected to a second power source (such as a low-potential
`side of a power source, GND) at the first plug, whereas the
`identification terminal is not connected to the second power
`source at the second plug.
`
`[0062] With this power control circuit, when an electronic
`instrument connected to the first plug of the USB cable is
`forcibly set to the slave side and another electronic instru-
`ment connected to the second plug of the USB cable is
`forcibly set to the master side, power from the other elec-
`tronic instrument connected to the second plug may be
`
`Page 16 of 25
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`

`

`US 2003/0030412 A1
`
`Feb. 13, 2003
`
`supplied through the USB power line to the electronic
`instrument connected to the first plug, to charge a recharge-
`able battery of the electronic instrument connected to the
`first plug.
`
`[0063] This makes it possible to charge an electronic
`instrument connected to the first plug, which ought to be on
`the master side, by an electronic instrument connected to the
`second plug, which ought to be on the slave side, enhancing
`the convenience to the user.
`
`In this case, the detection of the voltage level of the
`[0064]
`identification terminal may be invalidated, by way of
`example.
`
`[0065] Astill further embodiment of the present invention
`may comprise:
`
`[0066]
`
`any of the above the power control circuits;
`
`are chargeable battery in which charging thereof is
`[0067]
`controlled by the power control circuit; and
`
`a data transfer control circuit which controls USB
`[0068]
`data transfer.
`
`[0069] A yet further embodiment of the present invention
`relates to a charging method for an electronic instrument that
`is provided with a universal serial bus (USB) interface,
`comprising:
`
`supplying power from a first electronic instrument
`[0070]
`on a master side through a USB power line to a second
`electronic instrument on a slave side and charging a
`rechargeable battery of the second electronic instrument,
`when the first electronic instrument has been connected to a
`
`first plug of a USB cable and is set to the master side and the
`second electronic instrument has been connected to a second
`
`plug of the USB cable and is set to the slave side; and
`
`supplying power from the second electronic instru-
`[0071]
`ment on the master side through the USB power line to the
`first electronic instrument on the slave side and charging a
`rechargeable battery of the first electronic instrument, when
`the first electronic instrument has been connected to the
`
`second plug of the USB cable and is set to the slave side and
`the second electronic instrument has been connected to the
`
`first plug of the USB cable and is set to the master side.
`
`[0072] With this method, it is possible to set the first and
`second electronic instruments to be master and slave, respec-
`tively, and charge the rechargeable battery of the second
`electronic instrument from the power source of the first
`electronic instrument, if the battery of the second electronic
`instrument has run low, by way of example. Conversely, it
`is also possible to set the first and second electronic instru-
`ments to be slave and master, respectively, and charge the
`rechargeable battery of the first electronic instrument from
`the power source of the second electronic instrument, if the
`battery of the first electronic instrument has run low. This
`enables an improvement in convenience to the user.
`
`[0073] This method may further comprise turning off a
`supply of power to the data transfer control circuit which
`controls USB data transfer, or setting the data transfer
`control circuit to an energy-saving mode, in charge mode.
`
`[0074] This makes it possible to prevent wasteful con-
`sumption of power by the data transfer control circuit when
`
`in charge mode, facilitating a reduction in the energy con-
`sumption of the electronic instrument.
`
`[0075] This method may further comprise supplying
`power to an electronic instrument connected to the first plug
`from another electronic instrument connected to the second
`
`plug through the USB power line, and charging a recharge-
`able battery of the electronic instrument connected to the
`first plug, when the electronic instrument connected to the
`fir