Intermodulation distortion of class D audio amplifier using pulse density modulation

Abstract

In this paper, an analysis of intermodulation distortion of class D audio amplifier is presented. Class D audio amplifier uses MOSFETs in switching mode is designed. The amplifier system contains a modulator and an output low-pass filter. Both modulation techniques, pulse width modulation and pulse density modulation, are used to drive class D amplifier stage. The influence of switching frequency on total second- and third-order intermodulation distortion products is examined. It is shown that for pulse density modulation, total intermodulation distortion remains within the permissible range of values.