Patent ID: 8836419
Filing Date: 2014-09-16
Classification: H03F,H03K

Abstract:
1. A PWM comparator comprising a preamplifier circuit, a feedback circuit and a judge circuit; wherein the preamplifier circuit comprises two input-terminals respectively for receiving a high frequency triangle signal and an input audio signal, and the preamplifier circuit outputs the changes of waveform of the high frequency triangle signal and the input audio signal to the feedback circuit and the judge circuit; the feedback circuit is connected to the preamplifier circuit and the judge circuit, the feedback circuit comprises an internal current source, the feedback circuit adjusts the current from the current source to the input of the judge circuit, according to the waveform changes of the high frequency triangle signal received from the pre amplified preamplifier circuit, and a voltage level of PWM signals of the PWM comparator; the judge circuit is connected to the feedback circuit, the judge circuit obtains the changes of the high frequency triangle signal and the input audio signal based on a change of a input current of the judge circuit, and generates a comparison result according to a comparison of the high frequency triangle signal and the input audio signal.