Patent ID: 7495478

Claim:
A comparator circuit, comprising: a comparator section for comparing an input voltage and a threshold voltage, and for outputting a current in accordance with a result of the comparison between the input voltage and the threshold voltage, the comparator section including a constant current source for outputting a first current; and an amplifier circuit for amplifying the first current, and for outputting the first current thus amplified as a second current, the comparator section outputting the current that is an addition of the first current and the second current when the input voltage is more than the threshold voltage, whereas the comparator section outputting no current when the threshold voltage is more than the input voltage, wherein the comparator section includes: a first differential pair of a first NPN transistor and a first PNP transistor, which receive the input voltage and have a Darlington connection with each other; and a second differential pair of a second NPN transistor and a second PNP transistor, which receive the threshold voltage and have a Darlington connection with each other, and the amplifier circuit includes a third PNP transistor whose base and emitter are connected with base and emitter, respectively, of the first PNP transistor.