Patent ID: 8723555

Claim:
A comparator circuit, comprising: a first power source terminal having a first potential; a second power source terminal having a second potential different from the first potential; a detection voltage terminal; a reference voltage generator coupled between the first power source terminal and the second power source terminal, the reference voltage generator generating a middle potential which is a potential between the first potential and the second potential and outputting the middle potential at a middle potential node, the reference voltage generator further generating a reference voltage; a bias unit coupled between the first power source terminal and the middle potential node, the bias unit receiving the reference voltage and generating a corresponding reference voltage by using the first potential and the middle potential as energy sources thereof; and a comparator unit coupled between the first and second power source terminals and the detection voltage terminal, the comparator unit comprising: a first transistor of a first channel type and a second transistor of a second channel type coupled in series between the first power source terminal and the second power source terminal; and a third transistor of the first channel type and a fourth transistor of the second channel type coupled in series between the first power source terminal and the detection voltage terminal, wherein the second transistor and the fourth transistor are configured in a current mirror structure, the comparator unit compares a voltage difference arising between the detection voltage terminal and the second power source terminal with the corresponding reference voltage, and the corresponding reference voltage is applied between the control terminals of the first and third transistors.