Patent ID: 8115539

Claim:
An operational amplifier, comprising: a main amplifier; and an offset correction amplifier, the main amplifier and the offset correction amplifier including input terminals connected in common, wherein the main amplifier comprises: a first transconductance amplifier for measurement; a second transconductance amplifier for offset correction; and a first capacitor connected to an input terminal of the second transconductance amplifier, wherein the offset correction amplifier comprises: a third transconductance amplifier for measurement; a fourth transconductance amplifier for offset correction; and a second capacitor connected to one input terminal of the fourth transconductance amplifier, the offset correction amplifier including an output terminal connected to the first capacitor, and wherein the operational amplifier further comprises an offset voltage adjustment circuit provided to another input terminal of the fourth transconductance amplifier of the offset correction amplifier, to thereby correct an offset of an element to be connected to the input terminal.