Analysis of dynamic frequency response of class E amplifier

A dynamic response of the output voltage to the input supply voltage V_DD of a class E amplifier is derived with modeling the circuit by a low-frequency model and a high-frequency model. If the perturbation frequency is much lower than the switching frequency, the state-space averaging model of the class E amplifier can be approximated as a single-pole low-pass filter composed of the choke inductance L_RFC and the parallel combination of the switch resistance and the shunt capacitor resistance. The analysis in this paper is based on the steady-state behavior outside the designed conditions given in. Hence, the derivation is applicable even if the class E amplifier is operated in off-tuned conditions. The analytical results for the frequency response of a 1 MHz class E amplifier matched well with Pspice simulations at the perturbation frequency less than 100 kHz.