WIRELESS CHARGING DEVICE, A RECEIVER DEVICE, AND A METHOD OF OPERATING THE SAME

A wireless charging device () includes a driver unit () configured to generate one of a first AC voltage signal having a first frequency and a second AC voltage signal having a second frequency. Also, the wireless charging device () includes a transmitting unit () having a first coil () and a first capacitor () and configured to transmit the first AC voltage signal. Further, the transmitting unit () includes a second coil () and a second capacitor () and configured to transmit the second AC voltage signal. Additionally, the wireless charging device () includes a control unit () configured to detect a first receiver device () operating at the first frequency based on a change in a first voltage in the transmitting unit (), and detect a second receiver device () operating at the second frequency based on a change in a second voltage in the transmitting unit ().