Reducing distortion of audio class D (PWM) power amplifier by using feed-forward techniques

The chief characteristics of an audio class D (PWM) power amplifier are higher efficiency and larger distortion that other amplifiers. This paper discusses the principle of reducing distortion for class D amplifiers by using a feed-forward error-null technique, and provides an experimental circuit. The theoretical analysis and experimental results show that the technique is effective in reducing the distortion of class D power amplifiers: the distortion has decreased from 1% to 0.1%, the output power of the amplifier is 10 watt, the efficiency is 90% and the prospect is good.