A novel controller for switching audio power amplifier with digital input

A new controller, using bi-directional saw-tooth error correction (BSEC) for switching audio power amplifiers with digital PWM input is proposed. This control method is based on a pulsed edge correction approach using PWM audio signal input as a reference for power switching digital to analog converter. The proposed controller has excellent features such as wide error correction range and no limitation on the modulation index. The controller is implemented in the half-bridge class D amplifier and the performance is verified through hardware experiments. It delivers 100W into 4/spl Omega/ load with less than 0.2% of total harmonic distortion (THD) all over operating range with the maximum efficiency of 82%.