Circuit and method for a Class D amplifier. In one exemplary embodiment, an audio amplifier is disclosed. A closed loop configuration for driving high and low side driver transistors is provided, each circuit is compatible with advanced sub micron semiconductor processes. The analog time varying input is coupled to one input of a sigma delta analog to digital converter. A feedback signal from the output is also input to the analog to digital converter. A bit stream is output by the analog to digital converter. A decimator receives this bit stream and downconverts the samples to digital values at a lower frequency. A digital filter with adaptable coefficients is used to filter that signal and a digital pulse width modulator then develops an analog differential PWM signal. A predriver inputs the PWM signal and derives the output gating signals to control the high and low side drivers of a Class D amplifier.