Patent ID: 8314638

Claim:
A comparator circuit, comprising: first and second terminals, a reference voltage that determines a threshold voltage being inputted between the first and second terminals; a third terminal to which a standard voltage is inputted; a fourth terminal to which a target voltage that is to be detected and is based on the standard voltage is inputted; first and second transistors of a first conductivity type including control terminals connected to the first and second terminals, respectively, the first and second transistors flowing currents depending on a potential difference of the reference voltage; a third transistor of a second conductivity type connected between the first transistor and the fourth terminal; and a fourth transistor of the second conductivity type connected between the second transistor and the third terminal, the fourth transistor flowing a mirror current depending on a current passing through the third transistor, wherein a voltage depending on a voltage of an intermediate node between the second and fourth transistors is outputted as an output signal that includes a comparison result between the reference voltage and a voltage difference between the target voltage and the standard voltage.