Patent ID: 7852156

Claim:
A Class-D power amplifier having a distortion-suppressing function, wherein the Class-D power amplifier has a positive output end (Out) and a negative output end (Outb) for driving a loudspeaker, the Class-D power amplifier comprising: a gain control unit coupled with an audio signal; at least one PWM unit coupled with the gain control unit so as to receive an amplified audio signal output by the gain control unit and generate a PWM signal; at least one FET drive unit coupled with the PWM unit; at least one output stage FET unit coupled with the at least one FET drive unit, wherein the at least one FET drive unit receives the PWM signal output by the at least one PWM unit and turns on or off the at least one output stage FET unit according to the PWM signal, thereby driving the loudspeaker; and a level control unit comprising: at least one D flip-flop having two input ends, two output ends, and one R end (Reset), wherein the two input ends of each said D flip-flop are coupled with a high-level direct current signal of V cc and a clock signal (Clock), respectively, while the two output ends of each said D flip-flop are coupled with the gain control unit and left floating, respectively; and at least one XNOR gate having two input ends and one output end, wherein the two input ends of each said XNOR gate are coupled with the positive output end (Out) and the negative output end (Outb) of the Class-D power amplifier, respectively, while the output end of each said XNOR gate is coupled with the R end (Reset) of each said D flip-flop, wherein when the positive output end (Out) and the negative output end (Outb) of the Class-D power amplifier respectively and simultaneously output a high-level signal (High) and a low-level signal (Low) to the two input ends of each said XNOR gate, each said XNOR gate outputs the high-level signal to the at least one D flip-flop, and the at least one D flip-flop outputs the high-level signal to the gain control unit as feedback so as to control the gain control unit to reduce audio gain, thereby suppressing audio distortion.