CLASS-D AMPLIFIER WITH PULSE-WIDTH MODULATION COMMON-MODE CONTROL AND ASSOCIATED METHOD FOR PERFORMING CLASS-D AMPLIFICATION

摘要

A class-D amplifier (100, 300, 1200) includes a loop filter (102), a pulse-width modulation (PWM) circuit, an output circuit (106), and a common-mode control circuit (302, 500). The loop filter (102) receives an input signal (VIN) of the class-D amplifier (100, 300, 1200) to generate a filtered signal (VLF). The PWM circuit (106) converts a non-PWM signal (VSUM) into a PWM signal (VPWM), wherein the non-PWM signal (VSUM) is derived from at least the filtered signal (VLF). The output circuit (106) generates an output signal (VOUT) of the class-D amplifier (100, 300, 1200) according to the PWM signal (VPWM). The common-mode control circuit (302, 500) monitors a common-mode level of the output signal (VOUT) to generate a common-mode control signal (VCM_CTRL) for PWM common-mode control.