Digital control circuit for class-D audio power amplifier

This paper describes a digital speaker system with a hybrid PWM digital modulator for a class-D power audio amplifier using the oversampling and noise-shaping techniques. Results of measurements of the output signal spectrum for the audio frequency band with a sinusoidal input signal are shown. The presented speaker system achieves a signal-to-noise ratio (SNR) near to 75 dB in the audio band (20 Hz to 20 kHz).