Single chip design of closed-loop class D audio power amplifier

Abstract

A single chip design of class D audio power amplifier is presented. It is composed with a rail-to-rail operational amplifier and a closed-loop pulse width modulation. It achieves a maxim power of 3.75W and consumes about 1.9mA quiescent current as maxim efficiency is more than 90%. When sine wave input signal frequency is 1KHz and output power is 3.75W, the THE) of output signal is only 0.1%. The chip is designed with thermal protection which turns the device off when the junction temperature surpasses 150°C to prevent damage to the IC.