NEAR FIELD COMMUNICATION METHOD AND DEVICE IN WIRELESS POWER TRANSMISSION SYSTEM

The present invention relates to a near field communication method and device in a wireless power transmission system. A wireless power receiving device comprises: a power pick-up circuit configured to receive wireless power from a wireless power transmitting device having a primary coil by magnetic coupling to the wireless power transmitting device at an operating frequency and convert an alternating current signal generated from the wireless power into a direct current signal; a communication circuit configured to perform in-band communication with the wireless power transmitting device by using the operating frequency and perform out-band communication with the wireless power transmitting device or another device by using a frequency other than the operating frequency; and a control circuit configured to control an overall operation of the wireless power receiving device, wherein a first connection parameter for out-band communication between the wireless power transmitting device and the wireless power receiving device can be set equal to a second connection parameter for out-band communication between the wireless power transmitting device and another wireless power receiving device.