Power supply device and driving method thereof

• US 9,203,478 B2
• Filed: 03/24/2011
• Issued: 12/01/2015
• Est. Priority Date: 03/31/2010
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Saito, Toshihiko
• Primary Examiner(s): Fureman, Jared
• Assistant Examiner(s): BUKHARI, AQEEL H
• Application Number:
  US13/070,517
• Publication Number:
  US 20110241435A1
• Time in Patent Office: 1,713 Days
• US Class Current: 1/1
• 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 with a plurality of cells arranged in a matrix, each of the cells comprises one terminal of an antenna 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 first signal for a position detection operation and a second signal for a power feeding operation to a control terminal of the transistor,

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

wherein the transistor is configured to feed power and detect a position.

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.

11. The power supply device according to claim 1,

wherein a frequency of a high-frequency wave used for the position detection operation is 5 MHz or higher.

15. A table comprising the power supply device according to claim 1.

16. A wall comprising the power supply device according to claim 1.

17. A floor comprising the power supply device according to claim 1.

19. The power supply device according to claim 1,

wherein the transistor has both a function of feeding the power and a function of detecting the position.

20. The power supply device according to claim 1,

wherein a carrier density of the oxide semiconductor is less than 1×

10¹²/cm³.

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 a cell of the cells, comprising the steps of:

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

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

wherein a channel formation region of a thin film transistor of the power supply device comprises an oxide semiconductor,

wherein the thin film transistor is configured to feed power and detect a position alternately, and

wherein a switch control circuit transmits a first signal for the position detection operation and a second signal for the power feeding operation to a control terminal of the transistor.

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.

8. A power supply device comprising:

an antenna sheet with a plurality of cells arranged in a matrix, each of the cells comprises one terminal of an antenna that 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 first signal for a position detection operation and a second signal for a power feeding operation to a control terminal of the transistor,

wherein the transistor is configured to feed power and detect a position, and

wherein a channel formation region of the transistor comprises an oxide semiconductor containing In and Zn.

9. The power supply device according to claim 8,

wherein the antenna is a coiled antenna.

10. The power supply device according to claim 8,

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

12. A table comprising the power supply device according to claim 8.

13. A wall comprising the power supply device according to claim 8.

14. A floor comprising the power supply device according to claim 8.

18. The power supply device according to claim 8,

wherein the oxide semiconductor further contains Ga.