Patent ID: 7511537

Claim:
A comparator including a comparison core circuit unit having an output terminal for varying an output level in accordance with a voltage difference between a first voltage input to a gate terminal of a first transistor and a second voltage input to a gate terminal of a second transistor, the comparator comprising: a monitor circuit unit for outputting monitor current in accordance with the amount of current flowing through the second transistor in a transitional state in which the current amount changes and for stopping the flow of the monitor current when the second voltage is higher than the first voltage and current does not flow to the second transistor, wherein the monitor circuit unit includes a transistor having a gate terminal commonly shared with a gate terminal of the second transistor and a source terminal commonly shared with a source terminal of the second transistor, the transistor being smaller in size than the second transistor; a nonlinear amplification circuit unit for increasing the monitor current in a nonlinear manner and adding a bias for operating the comparison core circuit unit; and a plurality of second terminals, each inputting a different one of the second voltage, wherein the comparison core circuit unit includes the second transistor for each of the second terminals, and the monitor circuit unit includes a transistor for each of the second transistors, each transistor having a gate terminal and a source terminal commonly shared with the gate terminal and the source terminal of the associated one of the second transistors, and each transistor having a drain terminal connected to the first current mirror circuit.