WIRELESS CHARGING TRANSMITTER AND METHOD FOR OPERATING THE WIRELESS CHARGING TRANSMITTER

摘要

A wireless charging transmitter (12) has a phase-shift controlled inverter (20), a capacitor (18), a transmitter coil (16), and a control circuit. The phase-shift controlled inverter has an input for receiving a phase-shift signal, and first (u_A) and second output terminals (u_B) for providing an inverter output voltage. The capacitor has a first terminal coupled to the first output terminal of the phase-shift controlled inverter, and a second terminal. The transmitter coil has a first terminal coupled to the second terminal of the capacitor, and a second terminal coupled to the second terminal of the phase-shift controlled inverter. The control circuit has an input coupled to the second terminal of the capacitor for sampling a capacitor voltage (u_m1) of the capacitor, and an output for providing the phase-shift signal corrected for the phase error. The control circuit determines the phase error of the capacitor voltage relative to a phase of an inverter output voltage to ensure the wireless charging transmitter operates in resonance.