# US 9,520,739 B2 · Wireless charging circuit, wireless charging system and semiconductor device

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- Number: US 9,520,739 B2
- Document ID: US9520739B2
- Status: Granted
- Kind: B2
- Application number: 14/692,093
- Filed: 2015-04-21
- Published: 2015-08-13
- Granted: 2016-12-13
- Earliest claimed: 2012-03-12
- Assignees: Renesas Electronics Corporation
- Applicants: Renesas Electronics Corporation
- Inventors: Takefumi Endo; Masanori Kayama
- Web page: https://patentgrep.com/patent/US9520739B2

## CPC

- H02J 50/20: using microwaves or radio frequency waves
- G01R 19/0084: {Measuring voltage only}
- H02J 7/47: Arrangements for checking compatibility or authentication between one component, e.g. a battery or a battery charger, and another component, e.g. a power source
- H02J 50/12: of the resonant type
- H02J 50/70: involving the reduction of electric, magnetic or electromagnetic leakage fields
- H02J 50/80: involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
- H04B 5/26: using coils
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- H04B: TRANSMISSION

## Abstract

To satisfy the NFC communication standard in wireless charging with a shared antenna, used for NFC communication. A power supply unit includes a voltage step-down circuit 331, a charge control circuit 332, and a communication controller power supply circuit 333. The voltage step-down circuit includes a switching regulator 200, and a selection circuit 206 and 208 which can select an output path PT1 of the switching regulator and a bypass path PT2 of the switching regulator. The voltage step-down circuit includes a selection control circuit 207. The selection control circuit supplies voltage to the communication controller power supply circuit via the bypass path at the time of activating the communication controller. Since the output voltage of the series regulator stabilizes in a shorter time than the switching regulator, it becomes possible to keep the time from when RF power rises to when initial communication becomes possible, within standards.

## Claims

### Claim 1

A wireless communication device comprising:
a communication control circuit configured to transmit and receive control information;
a power control circuit including a first regulator circuit, a second regulator circuit and a selection circuit,
the power control circuit being configured to receive a source voltage, supply a power supply voltage to the communication control circuit and output a charging voltage to a battery,
the first regulator circuit being configured to input the source voltage and output a first voltage to the selection circuit;
the second regulator circuit being configured to input the source voltage and output a second voltage to the selection circuit;
wherein the selection circuit is configured to select and output the first voltage as the power supply voltage when a level of the first voltage reaches a predetermined level, and to select and output the second voltage as the power supply voltage when the level of the first voltage has not reached the predetermined level,
wherein an activation time of the second regulator is faster than that of the first regulator,
wherein the first regulator circuit includes a switching regulator, and
wherein the second regulator circuit includes a series regulator.

### Claim 2 (depends on 1)

A wireless communication device according to claim 1,
a power consumption of the first regulator is smaller than that of the second regulator.

### Claim 3 (depends on 1)

A wireless communication device according to claim 1,
wherein the selection circuit further includes a comparator circuit and a selection circuit,
wherein the comparator circuit is configured to compare the first voltage with a reference voltage and output a result voltage to the selection control circuit,
wherein the selection control circuit is configured to select the power supply voltage from the first voltage and the second voltage based on the result voltage.

### Claim 4 (depends on 3)

A wireless communication device according to claim 3,
wherein the control information includes a state of wireless communication.

### Claim 5 (depends on 1)

A wireless communication device according to claim 1, further comprising:
a coil antenna;
a rectifier circuit configured to couple with the coil antenna, the rectifier circuit being configured to rectify an alternating-current signal obtained via the coil antenna and output the source voltage to the power control circuit.