Power reception control device, power reception device, and electronic instrument

• US 8,160,654 B2
• Filed: 01/14/2008
• Issued: 04/17/2012
• Est. Priority Date: 01/17/2007
• 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: Onishi, Kota, Yoda, Kentaro, Kamijo, Takahiro, Sogabe, Haruhiko, Suzuki, Kuniharu, Kato, Hiroshi, Suzuki, Katsuya, Yamazaki, Manabu
• Primary Examiner(s): Afshar, Kamran
• Assistant Examiner(s): Zewari, Sayed T
• Application Number:
  US12/007,671
• Publication Number:
  US 20080169706A1
• Time in Patent Office: 1,555 Days
• Field of Search: 455/127.1, 455/117, 455/572, 455/573, 455/574
• US Class Current: 455/572
• CPC Class Codes: H02J 50/10 using inductive coupling
• 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 7/00045 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

Abstract

A power reception device utilizing non-contact power transmission causes a PMOS transistor as a switch circuit to be turned ON when a secondary battery is in a heavy-load state to form a path which bypasses a series regulator (LDO) as a power supply circuit, and supplies a charging current to the secondary battery through the bypass path. An offset may be provided between ON/OFF control threshold values of the PMOS transistor. The series regulator (LDO) may be entirely or partially set in a non-operating state when forming the bypass path.

Claims

1. 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 that includes a rectifier circuit and a regulator by electromagnetically coupling a primary coil and a secondary coil, the non-contact power transmission system transmitting an output voltage of the rectifier to the regulator, the regulator transmitting an output voltage of the regulator to a load from a voltage output node of the power reception device, the power reception control device comprising:

a power reception control circuit that monitors at least one of a voltage at an input terminal and a voltage at an output terminal of the regulator provided in the power reception device, and, when a capability of supplying power to the load has decreased due to a decrease in at least one of the voltage at the input terminal and the voltage at the output terminal, the power reception control circuit causing a switch circuit provided between the input terminal and the output terminal of the regulator to be turned ON, upon turn on of the switch circuit, the switch circuit forms a bypass path that directly connects the input terminal and the output terminal of the regulator, the output voltage of the rectifier circuit being transmitted to the load through the bypass path.

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

the regulator being a series regulator that functions as a power supply circuit;

and the load including a secondary battery.

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

the power reception control circuit causing the switch circuit to be turned ON or OFF based on the voltage at the input terminal of the regulator.

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

the power reception control circuit causing the switch circuit to be turned ON or OFF based on the voltage at the output terminal of the regulator.

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

the power reception control circuit causing the switch circuit to be turned ON based on the voltage at the input terminal of the regulator, and causing the switch circuit to be turned OFF based on the voltage at the input terminal of the regulator.

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

a second threshold voltage that causes the switch circuit to be turned OFF being set to be higher than a first threshold voltage that causes the switch circuit to be turned ON.

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

the power reception control device further including a switch control signal generation circuit that generates a switch control signal that causes the switch circuit to be turned ON/OFF, the switch control signal generation circuit including:

a first voltage divider resistor, a second voltage divider resistor, and a third voltage divider resistor that divide the voltage at the output terminal of the regulator;

a first hysteresis comparator, a voltage at a common connection point of the first voltage divider resistor and the second voltage divider resistor being applied to an inverting terminal of the first hysteresis comparator, and a reference voltage being applied to a non-inverting terminal of the first hysteresis comparator;

a second hysteresis comparator, a voltage at a common connection point of the second voltage divider resistor and the third voltage divider resistor being applied to an inverting terminal of the second hysteresis comparator, and the reference voltage being applied to a non-inverting terminal of the second hysteresis comparator; and

an RS flip-flop that is set based on a positive edge or a negative edge of an output voltage of the first hysteresis comparator, is reset based on a positive edge or a negative edge of an output voltage of the second hysteresis comparator, and outputs the switch control signal from its output terminal.

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

the power reception control circuit causing the switch circuit to be turned ON to form the bypass path while setting the entirety or part of the regulator in a non-operating state.

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

the non-operating state/operating state of the entirety or part of the regulator being controlled based on a switch control signal that causes the switch circuit to be turned ON/OFF.

10. A power reception device comprising:

the power reception control device as defined in claim 1;

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

a power supply control section that includes the regulator and the switch circuit that is provided between the input terminal and the output terminal of the regulator, and controls power supply to the load.

11. The power reception device as defined in claim 10,

the power reception device further including a bypass control circuit that is used to control the switch circuit to be turned ON/OFF, the power reception control circuit controlling the switch circuit to be turned ON/OFF by controlling an operation of the bypass control circuit.

12. The power reception device as defined in claim 11,

the switch circuit including a PMOS transistor, a source and a drain of the PMOS transistor being respectively connected to the input terminal and the output terminal of the regulator;

and

the bypass control circuit including;

an NMOS transistor, a source of the NMOS transistor being grounded and a drain of the NMOS transistor being connected to a gate of the PMOS transistor; and

a pull-up resistor that is connected between the gate of the PMOS transistor and the input terminal of the regulator.

13. An electronic instrument comprising:

the power reception device as defined in claim 10; and

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

14. The electronic instrument as defined in claim 13,

the electronic instrument being a portable terminal.

15. The power reception control device according to claim 1, wherein when the switch circuit is turned ON, the output voltage of the rectifier is transmitted directly to the load.