Embodiments of the present invention provide a sigma-delta modulated power supply that is operable to sum an input signal and a feedback signal, integrate the summed signal, asynchronously quantize the integrated signal, sample the quantized signal utilizing a pseudo-random osculating signal, and amplify the sampled signal. The power supply enables discrete implementation of a low-cost, spread spectrum controlled, sigma delta modulated power supply for spectrally pure, high efficiency, low EMI power amplification.