Class D audio amplifier with 4th order output filter and self-oscillating full-state hysteresis based feedback driving capacitive transducers

摘要

A practical solution is presented for the design of a non-isolated high voltage DC/AC power converter. The converter is intended to be used as a class D audio amplifier for a Dielectric Electro Active Polymer (DEAP) transducer. A simple and effective hysteretic control scheme for the converter (buck with fourth-order output filter) is developed and analyzed. The proposed design is verified experimentally by a 125 VAR prototype amplifier, capable of delivering a peak output voltage of 240 V within the frequency range of 100 Hz – 3.5 kHz. A peak efficiency of 87 % is reported.