Patent ID: 6906568
Filing Date: 2005-06-14
Classification: H03K

Abstract:
1. A hysteresis comparing device with constant hysteresis width, for receiving a first signal and a second signal and outputting a digital signal, the hysteresis comparing device comprising: a threshold voltage generator used to receive the first signal and output an upper threshold voltage and a lower threshold voltage, the threshold voltage generator comprising: a multiplexer, coupled to the threshold voltage generator, and used to receive the upper threshold voltage and the lower threshold voltage, wherein the multiplexer also outputs a multiplexing signal according to the digital signal, and the multiplexing signal is from one of the upper threshold voltage and the lower threshold voltage; and a next stage comparator, wherein one terminal of the next stage comparator is used to receive the multiplexing signal, and another one terminal is used to receive the second signal, and the next stage comparator outputs the digital signal, wherein the first signal is obtained by low-pass filtering the second signal.