Effect of dead time on harmonic distortion in class-Daudio power amplifiers

Abstract

A model is described for predicting the harmonic levels introduced by the use of dead time in class-D, PWM-driven audio power output stages. The model demonstrates that the harmonic levels are a function of load impedance, modulation depth, dead time and switching frequency. In addition, measurements show that, for audio applications, dead time is the dominant cause of power stage nonlinearity.