Power reception control device, power transmission control device, non-contact power transmission system, power reception device, power transmission device, and electronic instrument

• US 8,064,825 B2
• Filed: 02/15/2008
• Issued: 11/22/2011
• Est. Priority Date: 02/16/2007
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group), Sony Ericsson Mobile Communications Japan Incorporated (Sony Group Corp.)
• Original Assignee: Seiko Epson Corporation (Seiko Group), Sony Ericsson Mobile Communications (Sony Group Corp.)
• Inventors: Kamijo, Takahiro, Suzuki, Katsuya, Yamazaki, Manabu, Onishi, Kota, Jin, Mikimoto, Kato, Hiroshi, Kondo, Yoichiro, Suzuki, Kuniharu, Yoda, Kentaro, Sogabe, Haruhiko
• Primary Examiner(s): Milord; Marceau
• Application Number:
  US12/071,150
• Publication Number:
  US 20080200119A1
• Time in Patent Office: 1,376 Days
• Field of Search: 455/41.1, 455/522, 455/573, 455/574, 455/127.1, 455/572, 455/343.1, 455/292, 455/263, 455/13.4, 375/142, 375/130, 713/323, 713/300, 320108-109, 320114-115, 320/124, 320/119, 320/139
• US Class Current: 455/41.1
• CPC Class Codes: G01V 3/10 using induction coils
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/0044 specially adapted for holding portable devices containing batteries H02J7/0045 takes precedence
• CPC Class Codes: H04B 1/3883 Arrangements for mounting batteries or battery chargers
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• CPC Class Codes: H04B 7/00 Radio transmission systems, i.e. using radiation field H04B10/00, H04B15/00 take precedence

Abstract

A power-receiving-side control circuit of a power reception device performs intermittent load modulation by causing an NMOS transistor to be turned ON/OFF during normal power transmission. A power-transmission-side control circuit included in a power transmission control device of a power transmission device monitors, an intermittent change in the load of the power reception device during normal power transmission. The power-transmission-side control circuit determines that a foreign object has been inserted between a primary coil and a secondary coil and stops power transmission when an intermittent change in load cannot be detected. The amount of power supplied to the load may be compulsorily reduced when the load state of the load is heavy.

Claims

1. A power reception control device that is provided in a power reception device that is included in a non-contact power transmission system, the non-contact power transmission system transmitting power from a power transmission device to the power reception device by electromagnetically coupling a primary coil and a secondary coil and transmitting the power to a first load electrically connected to the power reception device, the power reception control device comprising:

a load modulation section that modulates a second load, the second load provided in the power reception device;

a power supply control section that controls power supply to the first load; and

a power-receiving-side control circuit that is provided in the power reception control device and controls the power reception device,

the power-receiving-side control circuit supplying power to the first load, and controlling the load modulation section to operate and change the second load to transmit a signal which enables the power transmission device to detect a foreign object during a period from a start of normal power transmission to an end.

2. The power reception control device as defined in claim 1,

the second load being changed periodically, one period is determined in a first period, the second load being changed at plural times in the first period, the plural times determined at given intervals, the given intervals determined at a second period.

3. The power reception control device as defined in claim 2,

the second load being changed at plural times only at a third period in the first period, the third period being shorter than the first period.

4. The power reception control device as defined in claim 1,

the power-receiving-side control circuit monitoring a load state of the first load, and compulsorily reducing the power supplied to the first load by controlling the power supply control section based on the load state of the first load.

5. The power reception control device as defined in claim 4,

the power supply control section including a power supply control transistor that is provided in a power supply path connected to the first load;

and

the power-receiving-side control circuit compulsorily reducing the power supplied to the first load by successively switching the power supply control transistor.

6. The power reception control device as defined in claim 4,

the power supply control section including a field effect transistor as a power supply control transistor that is provided in a power supply path connected to the first load;

and

the power-receiving-side control circuit compulsorily reducing the power supplied to the first load by reducing an output current of the field effect transistor by setting a gate voltage of the field effect transistor at an intermediate voltage between a gate voltage when the field effect transistor is completely turned ON and a gate voltage when the field effect transistor is completely turned OFF.

7. The power reception control device as defined in claim 4,

the power supply control section including a series regulator that stabilizes a voltage supplied to the first load;

and

the power-receiving-side control circuit monitoring the load state of the first load by detecting a voltage between terminals of the series regulator.

8. The power reception control device as defined in claim 4,

the power supply control section including a power supply control transistor that is provided in a power supply path connected to the first load;

and

the power-receiving-side control circuit monitoring the load state of the first load by detecting a voltage between terminals of the power supply control transistor.

9. The power reception control device as defined in claim 4,

the power-receiving-side control circuit monitoring the load state of the first load by detecting a current that flows through a power supply path of the power supply control section.

10. A power reception device comprising:

the power reception control device as defined in claim 1; and

a power reception section that converts an induced voltage in the secondary coil into a direct voltage.

11. An electronic instrument comprising:

the power reception device as defined in claim 10; and

a load of the power reception device, power being supplied to the load from the power reception device.

12. The power reception control device as defined in claim 1, the load modulation section periodically increasing and decreasing the second load, a level of the signal that enables the power transmission device to detect the foreign object changing in response to the change of the second load.

13. The power reception control device as defined in claim 1, the load modulation section including a switching device, the power-receiving-side control circuit controlling the switching device to periodically increase and decrease the second load.

14. A power transmission control device that is provided in a power transmission device that is included in a non-contact power transmission system, the non-contact power transmission system transmitting power from the power transmission device to a power reception device by electromagnetically coupling a primary coil and a secondary coil and transmitting the power to a first load electrically connected to the power reception device, the power reception device performing load modulation to intermittently change a second load during normal power transmission, the second load provided in the power reception device, the power transmission control device comprising:

a detection circuit that detects a change in the second load; and

a power-transmission-side control circuit that controls the power transmission device,

the power-transmission-side control circuit determining that a foreign object has been inserted between the primary coil and the secondary coil, and stopping the normal power transmission when a change in the second load cannot be detected during the normal power transmission.

15. The power transmission control device as defined in claim 14,

the second load being changed periodically, one period is determined in a first period, the second load being changed at plural times in the first period, the plural times determined at given intervals, the given intervals determined at a second period, and

the power-transmission-side control circuit detecting changes in the second load every first period, and the power-transmission-side control circuit stopping the normal power transmission when the power-transmission-side control circuit cannot detect a change of the second load in a given number of cycles.

16. The power transmission control device as defined in claim 14,

the detection circuit being a waveform detection circuit that detects a waveform of an induced voltage in the primary coil.

17. A power transmission device comprising:

the power transmission control device as defined in claim 14; and

a power transmission section that generates an alternating voltage and supplies the alternating voltage to the primary coil.

18. An electronic instrument comprising the power transmission device as defined in claim 17.

19. A non-contact power transmission system that transmits power from a power transmission device to a power reception device by electromagnetically coupling a primary coil and a secondary coil and transmits the power to a first load electrically connected to the power reception device, the system comprising:

the power transmission device including;

a detection circuit that detects a change of a second load, the second load provided in the power reception device; and

a power-transmission-side control circuit that controls the power transmission device;

the power reception device including;

a load modulation section that modulates the second load;

a power supply control section that controls power supply to the first load; and

a power reception control device that includes a power-receiving-side control circuit that controls the power reception device,

the power-receiving-side control circuit controlling the load modulation section to operate and change the second load when supplying power to the first load through the power supply control section during normal power transmission, the power-receiving-side control circuit reducing a load state of the first load by compulsorily reducing the power supplied to the first load by controlling the power supply control section based on the load state of the first load, and

the power-transmission-side control circuit determining that a foreign object has been inserted between the primary coil and the secondary coil, and stopping the normal power transmission when an intermittent change in the second load cannot be detected during the normal power transmission.