Third harmonic filtered 13.56 MHz Push-Pull Class-E Power Amplifier

A novel energy efficient power amplifier designed to drive an inductive load is presented in this paper. In this power amplifier the standard Class-E topology is extended towards a Push-Pull configuration with frequency tripling. By tuning the load network to the third harmonic of the switching frequency, gate driving losses have been decreased. Opportunities and restrictions related to the fundamental change in operation of the amplifier are clarified. Calculations and simulation results are shown as well as experimental results. Furthermore a circuit is presented to further reduce the required power of the gate drive circuit.