The wireless power transmitter 100 in the ping state 620 forms a wireless power signal to detect the wireless power receiver 200, modulates the wireless power signal modulated by the wireless power receiver 200, and acquires a power control message in a digital data format corresponding to a response to the detection signal from the modulated wireless power signal. The wireless power transmitter 100 may receive a power control message corresponding to the response to the detection signal to recognize the wireless power receiver 200 which is a subject of power transmission.
The detection signal formed to allowing the wireless power transmitter 100 in the ping state 620 to perform a digital detection process may be a wireless power signal formed by applying a power signal at a specific operating point for a predetermined period of time. The operating point may denote a frequency, duty cycle, and amplitude of the voltage applied to the transmitting (Tx) coil. The wireless power transmitter 100 may generate the detection signal generated by applying the power signal at a specific operating point for a predetermined period of time, and attempt to receive a power control message from the wireless power receiver 200.