Low-emi capacitively-coupled class-d amplifiers with voltage boosting

Abstract

The present invention is a Class-D amplifier including: a capacitively-coupled amplifier, configured to receive an input signal and a feedback signal and generate an error signal; and a loop filter, coupled to input capacitor and the feedback capacitor, configured to generate a processed signal according to the error signal; and a pulse-width modulation (PWM) generator, coupled to the loop filter, configured to generate a plurality of PWM signals according to the processed signal and a control signal; and a voltage boosting power stage, coupled to the PWM generator, configured to generate a boosted output signal according to the plurality of PWM signals, the control signal and a power supply, and to feedback the boosted output signal to the loop filter, wherein the maximum voltage of the boosted output signal is greater than the voltage of the power supply.