Abstract: An improved class BD (3-state) switching amplifier is provided requiring fewer power switching devices, and providing improved immunity to power-supply-induced distortion and greatly reduced notch distortion. Asymmetric gate drive delay circuitry produces time-coincident very short positive and negative drive pulses for very small signals, enabling linear performance down to zero input. The reference triangle wave is generated such that the positive amplitude of the triangle wave is modulated by the positive supply and the negative amplitude is modulated by the negative supply, eliminating to first order any supply-induced output distortion.