POWER SUPPLY DEVICE AND DRIVING METHOD THEREOF

• US 20110241435A1
• Filed: 03/24/2011
• Published: 10/06/2011
• Est. Priority Date: 03/31/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: SAITO, Toshihiko
• Granted Patent: US 9,203,478 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 50/23 characterised by the type of transmitting antennas, e.g. directional array antennas or Yagi antennas
• CPC Class Codes: H02J 50/402 the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H04B 5/266 One coil at each side, e.g. with primary and secondary coils
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

An object of the present invention is to provide a highly reliable power supply device which can withstand long-term use. Another object of the present invention is to provide a power supply device with reduced power consumption. The power supply device includes a cell including an antenna and a switch and performing position detection operation and power feeding operation; a high-frequency wave supply circuit; a switch control circuit; and a potential detecting circuit. One electrode of the antenna is connected to the high-frequency wave supply circuit through the switch, and the other thereof is connected to the potential detecting circuit. By the position detection operation, whether there is a power receiving device which gets close to a cell or not is detected. Only when the power receiving device is detected, power is supplied by the power feeding operation.

Claims

1. A power supply device comprising:

an antenna sheet provided with a plurality of cells arranged in a matrix, each of the cells comprises one terminal of an antenna is connected to one terminal of a transistor;

a high-frequency wave supply circuit connected to the other terminal of the transistor;

a potential detecting circuit connected to the other terminal of the antenna; and

a switch control circuit transmitting a signal to a control terminal of the transistor,

wherein a channel formation region of the transistor comprises an oxide semiconductor.

2. The power supply device according to claim 1,

wherein the antenna is a coiled antenna.

3. The power supply device according to claim 1,

wherein a frequency of a high-frequency wave supplied from the high-frequency wave supply circuit is 1 MHz or higher.

4. A method for driving a power supply device comprising a plurality of cells arranged in a matrix, a high-frequency wave supply circuit, a switch control circuit, and a potential detecting circuit and supplying power to a power receiving device which gets close to the cell, comprising the steps of:

detecting the cell to which the power receiving device gets close with a high-frequency position detection wave by position detection operation; and

supplying power with a high-frequency power feeding wave from the detected cell by power feeding operation.

5. The method for driving a power supply device according to claim 4,

wherein an operation period of the power feeding operation is longer than an operation period of the position detection operation.

6. The method for driving a power supply device according to claim 4,

wherein power of the high-frequency power feeding wave is larger than power of the high-frequency position detection wave.

7. The method for driving a power supply device according to claim 4,

wherein the high-frequency position detection wave and the high-frequency power feeding wave are high-frequency waves with a same frequency.