Power reception control device and power reception control method for non-contact power transmission

1. A power reception control device includable in a non-contact power transmission system that performs non-contact power transmission from a power transmission device to a power reception device through a primary coil and a secondary coil, the power reception device supplying power to a first load, the power reception control device comprising:

a power reception section that converts an induced voltage in the secondary coil into a direct-current voltage;

a load modulation section that modulates a second load of the power reception section; and

a power-reception-side control section that controls an operation of the power reception device,

the first load including a charge control device that controls power supplied to a battery,

the load modulation section being configured to transmit information from the power reception device to the power transmission device through the secondary coil and the primary coil utilizing load modulation of the second load, and

the power-reception-side control section being configured to reduce the power supplied to the battery by controlling a charge operation of the charge control device when the power-reception-side control section controls the load modulation section to transmit the information from the power reception device to the power transmission device.

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

the power-reception-side control section being configured to control the charge operation of the charge control device using a power supply control signal that is output to the charge control device.

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

the power-reception-side control circuit creating a load reduction period in which power supplied to the battery is reduced or stopped and causing the load modulation section to perform load modulation during the load reduction period.

4. An integrated circuit device, comprising:

the power reception control device as defined in claim 2 .

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

the power-reception-side control section controlling the load modulation section to transmit the information while the charge control device compulsorily reduces or stops power supplied to the battery.

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

the power-reception-side control circuit creating a load reduction period in which power supplied to the battery is reduced or stopped and causing the load modulation section to perform load modulation during the load reduction period.

7. An integrated circuit device, comprising:

the power reception control device as defined in claim 5 .

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

the power-reception-side control section being configured to transmit a foreign object detection pattern that allows the power transmission device to detect a takeover state by causing the load modulation section to modulate the second load, the takeover state being a state in which the power transmission device: (1) regards a foreign object placed between the primary coil and the secondary coil as the power reception device and (2) continues power transmission.

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

the power-reception-side control circuit creating a load reduction period in which power supplied to the battery is reduced or stopped and causing the load modulation section to perform load modulation during the load reduction period.

10. An integrated circuit device, comprising:

the power reception control device as defined in claim 8 .

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

the power-reception-side control circuit creating a load reduction period in which power supplied to the battery is reduced or stopped and causing the load modulation section to perform load modulation during the load reduction period.

12. An integrated circuit device, comprising:

the power reception control device as defined in claim 11 .

13. An integrated circuit device, comprising:

the power reception control device as defined in claim 1 .

14. An electronic instrument, comprising:

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

the secondary coil.

15. An electronic instrument, comprising:

the power reception control device as defined in claim 1 ;

the charge control device; and

the battery.

16. A non-contact power transmission system, comprising:

the power reception control device as defined in claim 1 ;

the power transmission device;

the primary coil; and

the secondary coil.

17. A power reception control method for a non-contact power transmission system that performs non-contact power transmission from a power transmission device to a power reception device through a primary coil and a secondary coil, the power reception device supplying power to a first load that includes a charge control device for controlling power supplied to a battery, the power reception method comprising:

operating a power reception section and converting an induced voltage in the secondary coil into a direct-current voltage;

supplying power to the first load;

modulating a second load of the power reception section;

transmitting information from the power reception device to the power transmission device through the secondary coil to the primary coil utilizing a load modulation of the second load; and

reducing the power supplied from the power reception section to the battery by controlling a charge operation of the charge control device when the information is transmitted from the power reception device to the power transmission device.

18. The power reception control method as defined in claim 17 , further comprising:

transmitting the information while the charge control device compulsorily reduces or stops power supplied to the battery.