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

• US 20080197804A1
• Filed: 02/15/2008
• Published: 08/21/2008
• 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 Japan Incorporated (Sony Group Corp.)
• Inventors: Suzuki, Katsuya, Yamazaki, Manabu, Onishi, Kota, Kato, Hiroshi, Kamijo, Takahiro, Suzuki, Kuniharu, Yoda, Kentaro, Sogabe, Haruhiko
• Granted Patent: US 8,054,036 B2
• Time in Patent Office: Days
• US Class Current: 320/108
• 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 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00045 Authentication, i.e. circuits for checking compatibility between one component, e.g. a battery or a battery charger, and another component, e.g. a power source
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/0044 specially adapted for holding portable devices containing batteries H02J7/0045 takes precedence

Abstract

A power transmission device performs power-saving power transmission that transmits a small amount of power as compared with normal power transmission when the power transmission device has detected that a battery of a load has been fully charged so that the operation of a charge control device (charge control IC) of the load is maintained, thereby enabling recharging due to a charge management function of the charge control device. Since the load state of a power reception device increases when recharging has started, the power transmission device detects an increase in the load state and changes power transmission from power-saving power transmission to normal power transmission. When the power reception device has been removed during power-saving power transmission, the power transmission device detects that the power reception device has been removed, and stops continuous power transmission so that unnecessary power consumption does not occur.

Claims

1. A power transmission control device provided in a power transmission device of 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 to transmit the power to a load of the power reception device, the power transmission control device comprising:

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

when the power transmission device has detected that a battery included in the load has been fully charged, the power-transmission-side control circuit stopping normal power transmission to the power reception device and performing power-saving power transmission that transmits a small amount of power as compared with the normal power transmission.

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

the load of the power reception device including a charge control device that manages charging the battery;

and

the power transmission device controlling power transmission so that the charge control device maintains an operating state, even after the battery has been fully charged, during the power-saving power transmission.

3. The power transmission control device as defined in claim 1,

the power-transmission-side control circuit changing power transmission from the normal power transmission to the power-saving power transmission when receiving a save command that requests the power-saving power transmission from the power reception device.

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

the power-transmission-side control circuit monitoring a load state of the power reception device during the power-saving power transmission;

and

when the power-transmission-side control circuit has detected that the load state of the power reception device has changed from a low-load state to a high-load state by starting recharge of the battery included in the load, the power-transmission-side control circuit changing power transmission from the power-saving power transmission to the normal power transmission.

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

the power-transmission-side control circuit intermittently monitoring the load state of the power reception device at given intervals during the power-saving power transmission.

6. The power transmission control device as defined in claim 1,

the power-transmission-side control circuit changing power transmission from the power-saving power transmission to the normal power transmission in a given cycle during the power-saving power transmission, and monitoring a response from the power reception device relating to the change from the power-saving power transmission to the normal power transmission;

the power-transmission-side control circuit again changing power transmission from the normal power transmission to the power-saving power transmission when receiving a save command that requests the power-saving power transmission from the power reception device; and

when the power-transmission control circuit cannot receive the save command from the power reception device, the power-transmission-side control circuit determining that the power reception device has been removed and stopping continuous power transmission.

13. A power transmission device comprising:

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

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

15. An electronic instrument comprising the power transmission device as defined in claim 13.

7. A power reception control device provided in a power reception device of 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 to transmit the power to a load of the power reception device, the power reception control device comprising:

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

when a battery included in the load has been fully charged, the power-reception-side control circuit performing control that the power reception device transmits information that indicates that the battery has been fully charged to the power transmission device.

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

the power-reception-side control circuit performing control that the power reception device transmits a save command that requests power-saving power transmission to the power transmission device when the power reception control device has detected that the battery has been fully charged and a power transmission frequency of the power transmission device is a frequency other than a power-saving power transmission frequency.

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

the power reception control device further including:

a full-charge detection circuit that detects whether or not the battery has been fully charged; and

a frequency detection circuit that detects the power transmission frequency of the power transmission device,

the full-charge detection circuit detecting whether or not the battery has been fully charged based on an ON/OFF state of a light-emitting device that indicates a charge state of the battery; and

the power-reception-side control circuit determining whether or not the power transmission frequency of the power transmission device is a frequency other than the power-saving power transmission frequency based on a detection result of the frequency detection circuit.

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

the full-charge detection circuit determining that the battery has been fully charged when the light-emitting device has been successively turned OFF for a given period of time.

14. A power reception device comprising:

the power reception control device as defined in claim 7; and

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

16. An electronic instrument comprising:

the power reception device as defined in claim 14; and

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

11. A non-contact power transmission system comprising a power transmission device and a power reception device, the non-contact power transmission system transmitting power from the power transmission device to the power reception device by electromagnetically coupling a primary coil and a secondary coil to transmit the power to a load of the power reception device,

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

the power reception device including;

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

a full-charge detection circuit that detects whether or not a battery has been fully charged; and

a frequency detection circuit that detects a power transmission frequency of the power transmission device;

the load of the power reception device including;

the battery; and

a charge control device that manages charging the battery, detects that the battery requires recharging after the battery has been fully charged, and recharges the battery;

the power-reception-side control circuit performing control that the power reception device transmits a save command that requests power-saving power transmission to the power transmission device when the full-charge detection circuit has detected that the battery included in the load has been fully charged and the frequency detection circuit has detected that a power transmission frequency of the power transmission device is a frequency other than a power-saving power transmission frequency;

the power-transmission-side control circuit changing power transmission from normal power transmission to the power-saving power transmission when receiving the save command from the power reception device during the normal power transmission;

the power-transmission-side control circuit monitoring a load state of the power reception device during the power-saving power transmission, and, when the power-transmission-side control circuit has detected that the load state of the power reception device has changed from a low-load state to a high-load state when recharging of the battery included in the load has started, the power-transmission-side control circuit changing power transmission from the power-saving power transmission to the normal power transmission; and

the power-transmission-side control circuit changing power transmission from the power-saving power transmission to the normal power transmission in a given cycle during the power-saving power transmission, monitoring a response from the power reception device relating to the change from the power-saving power transmission to the normal power transmission, again changing power transmission from the normal power transmission to the power-saving power transmission when a save command that requests the power-saving power transmission has been received from the power reception device, and determining that the power reception device has been removed when the power-transmission-side control circuit cannot receive the save command from the power reception device and stopping continuous power transmission.

12. The non-contact power transmission system as defined in claim 11,

the power transmission control device intermittently monitoring the load state of the power reception device at given intervals, the given intervals being shorter than intervals when the power-transmission-side control circuit cyclically changes power transmission from the power-saving power transmission to the normal power transmission during the power-saving power transmission.