A simple class-D audio power amplifier using a passive CT ΣΔ modulator for medium quality sound systems

Abstract

This paper presents a class-D power amplifier for medium quality sound systems using a second-order passive sigma-delta modulator (ΣΔM). The ΣΔM controls an output power stage consisting of a H-bridge. The loop filter of the ΣΔM was designed using a optimization procedure based on genetic algorithm (GA), that takes into account several parameters. This system was implemented using discrete components and the experimental results show that a DR of 75 dB is achieved with a peak signal-to-noise-plus-distortion ratio (SNDR) of 54 dB.