Apparatus and method for a class D audio power amplifier with a higher-order sigma-delta topology

A class D power amplifier is provided to drive a low impedance load for audio applications. The amplifier includes a sigma-delta modulator circuit including three or more integrators that are arranged for third or higher order sigma-delta modulation. Also, the sigma-delta modulator circuit includes a quantizer circuit that is arranged to provide a sigma-delta modulator output signal based on a three-level switching scheme. The class D power amplifier drives a speaker based on the three-level switching scheme so that the output switches between three levels: VDD, 0, and -VDD, based on the input signal.