Pulse width modulation circuit having noise-prevention function

The present invention provides a pulse width modulation circuit in cooperation with two switching elements. The pulse width modulation circuit comprises: a signal-generation module to receive and invert a feedback signal, so as to generate a first reference signal and a second reference signal; a low-pass filter module to pass the low-frequency band and generate a first comparison signal and a second comparison signal; a comparator module to compare the first reference signal and the first comparison signal for generating the first pulse signal, and to compare the second reference signal and the second comparison signal for generating the second pulse signal; and a flip-flop to receive the first and second pulse signals. The first pulse signal and second pulse signal alternatively trigger the flip-flop to generate a pulse signal for controlling one of the switching elements to turn on/off, thereby maintaining the feedback signal within a predetermined range.