Abstract: Power consumption of an output stage such as a class-D output stage may depend on the amplitude and the activity of the signal being output. Here, control signals may be generated to independently control coupled switches of the output stage and to provide a tri-state control scheme for the output stage. These control signals may be generated based on durations of different levels of an input signal over one or more periods of time.

Abstract: An ADC and method comprises a hybrid-type sigma-delta modulator comprising a digital delta-stage and an analog sigma-stage, wherein the analog sigma-stage comprises an analog low-pass filter adapted to only pass a low frequency audio band between 0-20 khz of a PWM wave, and wherein the digital delta-stage comprises a PWM wave generator; a pair of MOSFETs; and a power supply unit outputting voltage to the pair of MOSFETs. The ADC comprises a comparator attached to the hybrid-type sigma-delta modulator; a low-pass filter configured in a digital domain and for receiving a signal output of the comparator and remove high-frequency components of the comparator output above the audio band; a PWM back converter adapted to receive the filtered signal output and translate the digital low-pass filtered signal output to a power supply transient value in a digital format; and a dither signal source for injecting a dither signal to the digital delta-stage.