Method and apparatus for detecting efficiency of wireless power transmission

1. A method of detecting an efficiency of a wireless power transmission from a source device to a target device, the method comprising:

receiving, from the target device, information about power used by the target device;

determining a first power of a power amplifier (PA) of the source device based on the information about the power used by the target device;

transmitting, to the target device, wireless power corresponding to the first power;

determining a second power of the PA in response to a current of the PA converging to a constant level, wherein the current of the PA is changed until the target device receives wireless power corresponding to the information about the power used by the target device; and

calculating the efficiency of the wireless power transmission based on the second power and the information about power used by the target device.

2. The method of claim 1 , further comprising:

receiving, from the target device, information about power that is received by the target device,

wherein the efficiency is calculated based on the information about the power that is received by the target device and the second power.

3. The method of claim 1 , further comprising in response to the current of the PA increasing, increasing a power level of the PA until the current of the PA becomes constant.

4. The method of claim 1 , further comprising:

interrupting an operation of the source device, in response to the calculated efficiency being lower than a reference efficiency.

5. A method of detecting an efficiency of a wireless power transmission from a source device to a target device, the method comprising:

receiving, from the target device, information about power used by the target device;

determining an output power of a power amplifier (PA) of the source device based on the information about power used by a target device;

transmitting, to the target device, wireless power corresponding to the output power;

receiving, from the target device, information about power that is received by the target device, wherein the information about the power that is received by the target device comprises information about a current flowing in a load modulator of the target device, in a state in which a connection to a load of the target device is blocked and the received power inputted to the load modulator of the target device; and

calculating the efficiency of the wireless power transmission, based on the information about the power that is received by the target device and the output power.

6. The method of claim 5 , further comprising:

interrupting an operation of a source device, in response to the calculated efficiency being lower than a reference efficiency.

7. A computer-readable storage medium having stored therein program instructions to cause a processor to execute a method of detecting an efficiency of a wireless power transmission from a source device to a target device, the method comprising:

receiving, from the target device, information about power used by the target device;

determining a first output power of a power amplifier (PA) of the source device based on the information about power used by the target device;

transmitting, to the target device, wireless power corresponding to the first power;

determining a second power of the PA in response to a current of the PA converging to a constant level, wherein the current of the PA is changed until the target device receives wireless power corresponding the information about the power used by the target device; and

calculating the efficiency of the wireless power transmission, based on the second power and the information about the power used by the target device.

8. A wireless power transmitter, comprising:

a controller to determine a first power of a power amplifier (PA) of the wireless power transmitter based on information about power used by a target device received from the target device; and

a resonator to transmit, to the target device, wireless power corresponding to the first power,

wherein the controller

determines a second power of the PA in response to a current of the PA converging to a constant level, wherein the current of the PA is changed until the target device receives wireless power corresponding the information about the power used by the target device, and

calculates an efficiency of a wireless power transmission, based on the second power and the information about power used by the target device.

9. The wireless power transmitter of claim 8 , wherein the controller receives the information about the power used by the target device from the target device.

10. The wireless power transmitter of claim 8 , wherein the controller receives, from the target device, information about power that is received by the target device, and calculates the efficiency based on the information about the power that is received by the target device and the second power.

11. The wireless power transmitter of claim 8 , wherein, in response to the current of the PA increasing, the controller increases a power level of the PA until the current of the PA becomes constant.

12. The wireless power transmitter of claim 8 , wherein, in response to the calculated efficiency being lower than a reference efficiency, the controller interrupts an operation of a source device.

13. A wireless power transmitter, comprising:

a controller to determine an output power of a power amplifier (PA) of the wireless power transmitter based on information about power used by a target device; and

a resonator to transmit, to the target device, wireless power corresponding to the output power,

wherein the controller

receives, from the target device, information about power that is received by the target device, wherein the information about the power that is received by the target device comprises information about a current flowing in a load modulator of the target device, in a state in which a connection to a load of the target device is blocked and the received power inputted to the load modulator of the target device, and

calculates an efficiency of a wireless power transmission, based on the information about the power that is received by the target device and the output power.

14. The wireless power transmitter of claim 13 , wherein, in response to the calculated efficiency being lower than a reference efficiency, the controller interrupts an operation of a source device.

15. The wireless power transmitter of claim 13 , wherein, in response to a value of a current of the output power being equal to or greater than a set value determined based on the efficiency and the output power, the controller interrupts the operation of the source device.