ZVS condition predicting sensor for class E amplifier

A method that predicts the zero-voltage switching (ZVS) condition is presented for the class E amplifier operating at any duty ratio. The prediction is obtained in real-time by observing the switch and shunt capacitor current waveforms with a simple analog-digital circuit. Using this method, a control and/or protection circuit that ensures the ZVS operation may become feasible. Simulation and experimental results showed that the proposed ZVS prediction circuit worked properly.