Device and method for wirelessly transmitting power on basis of reestablishment of out-band communication

1. A wireless power receiver for receiving wireless power based on an out-band communication, comprising:

a power pickup circuit configured to receive wireless power from a wireless power transmitter based on magnetic coupling with the wireless power transmitter in an operation frequency and transform an alternate current (AC) signal generated by the wireless power to a direct current (DC) signal;

a communication/control circuit configured to be provided with the DC signal from the power pickup circuit, perform a handover to the out-band communication using a frequency except the operating frequency in an in-band communication using the operation frequency, transmit power characteristic information to the wireless power transmitter or receive the power characteristic information from the wireless power receiver based on the out-band communication before entering a power transfer phase, and perform a process of saving power state information determined during the power transfer phase; and

a load configured to receive the direct current from the power pickup circuit.

2. The wireless power receiver of claim 1 , wherein the out-band communication is Bluetooth low energy (BLE), and

wherein the communication/control circuit transmits or receives the power characteristic information based on a generic attribute profile (GATT) of the BLE.

3. The wireless power receiver of claim 1 , wherein the process of saving the power state information includes:

receiving, by the communication/control circuit, a save request message for requesting a saving of the power state information based on the out-band communication from the wireless power transmitter; and

transmitting a save response message for identifying the saving of the power state information to the wireless power transmitter based on the out-band communication.

4. The wireless power receiver of claim 3 , wherein the communication/control circuit includes an in-band communication module configured to perform the in-band communication and an out-band communication module configured to perform the out-band communication, and

wherein the out-band communication module transfers the power state information to the in-band communication module based on the save response message of power information.

5. The wireless power receiver of claim 3 , wherein the save request message includes at least one of device ID information, device address information, power level information, and a public key.

6. The wireless power receiver of claim 1 , wherein the communication/control circuit is configured to perform a process of exchanging the power state information with the wireless power transmitter in a reconnection after a disconnection of the out-band communication.

7. The wireless power receiver of claim 6 , wherein the process of exchanging the power state information includes:

receiving, by the communication/control circuit, a power information request message from the wireless power transmitter;

transmitting a power information response message to the wireless power transmitter; and

performing a power calibration.

8. The wireless power receiver of claim 7 , wherein the power information response message includes at least one of device ID information, device address information, power level information, and a public key.

9. The wireless power receiver of claim 7 , wherein the process of exchanging the power state information further includes:

changing, by the communication/control circuit, a power contract by performing a renegotiation phase with the wireless power transmitter based on the out-band communication.

10. The wireless power receiver of claim 9 , wherein the communication/control circuit is configured to perform a process of saving updated power state information during the renegotiation phase.

11. A wireless power transmitter for performing an authentication based on an out-band communication, comprising:

a power conversion circuit configured to transmit wireless power to a wireless power receiver based on magnetic coupling with the wireless power receiver in an operation frequency; and

a communication/control circuit configured to perform a handover to the out-band communication using a frequency except the operating frequency in an in-band communication using the operation frequency, receive power characteristic information from the wireless power receiver or transmit power characteristic information to the wireless power receiver based on the out-band communication before entering a power transfer phase, and perform a process of saving power state information determined during the power transfer phase.

12. The wireless power transmitter of claim 11 , wherein the out-band communication is Bluetooth low energy (BLE), and

wherein the communication/control circuit transmits or receives the power characteristic information based on a generic attribute profile (GATT) of the BLE.

13. The wireless power transmitter of claim 11 , wherein the process of saving the power state information includes:

transmitting, by the communication/control circuit, a save request message for requesting a saving of the power state information based on the out-band communication to the wireless power receiver; and

receiving a save response message for identifying the saving of the power state information from the wireless power receiver based on the out-band communication.

14. The wireless power transmitter of claim 13 , wherein the communication/control circuit includes an in-band communication module configured to perform the in-band communication and an out-band communication module configured to perform the out-band communication, and

wherein the out-band communication module transfers the power state information to the in-band communication module based on the save response message of power information.

15. The wireless power transmitter of claim 13 , wherein the save request message includes at least one of device ID information, device address information, power level information, and a public key.

16. The wireless power transmitter of claim 11 , wherein the communication/control circuit is configured to perform a process of exchanging the power state information with the wireless power receiver in a reconnection after a disconnection of the out-band communication.

17. The wireless power transmitter of claim 16 , wherein the process of exchanging the power state information includes:

transmitting, by the communication/control circuit, a power information request message to the wireless power receiver;

receiving a power information response message from the wireless power receiver; and

performing a power calibration.

18. The wireless power transmitter of claim 17 , wherein the power information response message includes at least one of device ID information, device address information, power level information, and a public key.

19. The wireless power transmitter of claim 17 , wherein the process of exchanging the power state information further includes:

changing, by the communication/control circuit, a power contract by performing a renegotiation phase with the wireless power receiver based on the out-band communication.

20. The wireless power transmitter of claim 19 , wherein the communication/control circuit is configured to perform a process of saving updated power state information during the renegotiation phase.