WIRELESS POWER TRANSMITTER FOR EXCLUDING CROSS-CONNECTED WIRELESS POWER RECEIVER AND METHOD FOR CONTROLLING THE SAME

1 . A method for controlling a wireless power transmitter configured to transmit power to a wireless power receiver, the method comprising:

receiving a first signal from the wireless power receiver, wherein the first signal comprises load detection indication bits;

detecting a change in load of the wireless power transmitter caused by placement of the wireless power receiver in a charging area of the wireless power transmitter, based on the load detection indication bits; and

determining whether to transmit a second signal to the wireless power receiver based on detecting the change in load of the wireless power transmitter.

2 . The method of claim 1 , wherein determining whether to transmit a second signal to the wireless power receiver comprises transmitting the second message in response to detecting the change in load of the wireless power transmitter and receiving the first signal.

3 . The method of claim 1 , wherein the load detection indication bits are one of 000, 001, 010, 011, 100 and 101.

4 . The method of claim 2 , further comprising:

if the load detection indication bits is 000, determining that the change in load of the wireless power transmitter cannot be detected even though the wireless power receiver is placed in the charging area of the wireless power transmitter.

5 . The method of claim 4 , wherein determining whether to transmit the second signal to the wireless power receiver comprises not transmitting the second signal to the wireless power receiver, in response to detecting that the load detection indication bits is 000.

6 . The method of claim 3 , further comprising:

if the load detection indication bits is 001, determining that a category of the wireless power receiver is category 1;

if the load detection indication bits is 010, determining that the category of the wireless power receiver is category 2;

if the load detection indication bits is 011, determining that the category of the wireless power receiver is category 3;

if the load detection indication bits is 100, determining that the category of the wireless power receiver is category 4; and

if the load detection indication bits is 101, determining that the category of the wireless power receiver is category 5.

7 . The method of claim 1 , wherein the second signal is used for joining the wireless power receiver to a wireless power network associated with the wireless power transmitter to transmit power to the wireless power receiver.

8 . A wireless power transmitter configured to transmit power to a wireless power receiver, the wireless power transmitter comprising:

a resonant signal generator configured to transmit power to the wireless power receiver;

a wireless communication unit configured to receive a first signal from the wireless power receiver, wherein the first signal comprises load detection indication bits; and

a controller configured to:

detect a change in load of the wireless power transmitter caused by placement of the wireless power receiver in the charging area of the wireless power transmitter, based on the load detection indication bits, and

determine to transmit a second signal to the wireless power receiver based on detecting the change in load of the wireless power transmitter.

9 . The wireless power transmitter of claim 8 , wherein the controller is configured to transmit the second signal in response to detecting the change in load of the wireless power transmitter and receive the first signal.

10 . The wireless power transmitter of claim 8 , wherein the load detection indication bits are one of 000, 001, 010, 011, 100 and 101.

11 . The wireless power transmitter of claim 10 , wherein the controller is configured to determine that the change in load of the wireless power transmitter cannot be detected even though the wireless power receiver is placed in the charging area of the wireless power transmitter, if the load detection indication bits is 000.

12 . The wireless power transmitter of claim 11 , wherein the controller is configured not to transmit the second signal to the wireless power receiver, in response to detecting that the load detection indication bits is 000.

13 . The wireless power transmitter of claim 10 , wherein the controller is configured to:

if the load detection indication bits is 001, determine that a category of the wireless power receiver is category 1;

if the load detection indication bits is 010, determine that the category of the wireless power receiver is category 2;

if the load detection indication bits is 011, determine that the category of the wireless power receiver is category 3;

if the load detection indication bits is 100, determine that the category of the wireless power receiver is category 4; and

if the load detection indication bits is 101, determine that the category of the wireless power receiver is category 5.

14 . The wireless power transmitter of claim 11 , wherein the second signal is used for joining the wireless power receiver to a wireless power network associated with the wireless power transmitter to transmit power to the wireless power receiver.

15 . A method for controlling a wireless power transmitter configured to transmit power to a wireless power receiver, the method comprising:

detecting a change in load of the wireless power transmitter caused by placement of the wireless power receiver in the charging area of the wireless power transmitter at a first time point during application of a detection power to a resonant signal generator of the wireless power transmitter;

receiving a first signal from the wireless power receiver at a second time point; and

determining whether to transmit a second signal to the wireless power receiver based on a difference between the first time point and the second time point.

16 . A wireless power transmitter configured to transmit power to a wireless power receiver, the wireless power transmitter comprising:

a resonant signal generator configured to transmit power to the wireless power receiver;

a controller configured to detect a change in load of the wireless power transmitter caused by placement of the wireless power receiver in the charging area of the wireless power transmitter at a first time point during which the resonant signal generator receives a detection power; and

a wireless communication unit configured to receive a first signal from the wireless power receiver at a second time point,

wherein the controller is configured to determine whether to transmit a second signal to the wireless power receiver based on a difference between the first time point and the second time point.