Analysis and Design of Class DE Amplifier With Nonlinear Shunt Capacitances

In this paper, equations for waveforms and design relationships are derived for class DE amplifiers with nonlinear shunt capacitances. Using the analytical waveform equations, it is shown that the nonlinearity of the shunt capacitances affects the waveforms only during the dead-time intervals. Additionally, the waveforms with nonlinear and linear shunt capacitances are not very different if class E zero-voltage switching/zero-derivative switching conditions are satisfied. The operation of a class DE amplifier has two dead-time intervals in one period. The switch-voltage waveforms for both dead-time intervals exhibit symmetry. Therefore, the nonlinearity does not have any effect on the series-resonant-circuit elements. As a result, analytical design equations indicate that the series-resonant-circuit elements are independent of the nonlinearity of the shunt capacitances when the supply voltage and the output power are given as design specifications, which is an important result of this paper. The validity of our analysis is confirmed by PSpice simulations and the circuit experiment.