Patent ID: 7095263

Claim:
A hysteresis circuit device, comprising: an input voltage level generator, said input voltage level generator comprises: a first current source, wherein a terminal of said first current source is coupled to a system voltage source; a second current source, wherein a terminal of said second current source is coupled to a ground; a plurality of serial resistors coupled to an input signal and divided by said input signal into a first serial resistors part and a second serial resistors part, wherein a terminal of said plurality of serial resistors is coupled to another terminal of said first current source, and another terminal of said plurality of serial resistors is coupled to another terminal of said second current source; a first multiplexer including a terminal coupled to said first serial resistors part, and controlled by a first selection control line to select an output voltage of said first serial resistors part to be an output of said first multiplexer; a second multiplexer including a terminal coupled to said second serial resistors part, and controlled by a second selection control line to select an output voltage of said second serial resistors part to be an output of said second multiplexer; a switch receiving said outputs of said first and second multiplexers and outputting a switch output signal according to a digital signal; and a comparator including a first input terminal to receive said switch output signal, a second input terminal coupled to a reference signal, and an output terminal to output said digital signal.