Patent ID: 8310306

Claim:
An operational amplifier, comprising: a first amplifier to which an input signal is applied; and a second amplifier to which an output of the first amplifier is applied, wherein the second amplifier includes: a first transistor including a first gate to which the output of the first amplifier is applied; and a second transistor including a second gate to which the output of the first amplifier is applied, and a drain coupled to a source of the first transistor, the second gate being connected to the first gate, wherein the first amplifier amplifies a potential difference between a potential of an input signal applied to a first input transistor and a potential of an input signal applied to a second input transistor, and outputs the amplified potential difference, a drain voltage of the first input transistor is supplied to the first gate of the first transistor and the second gate of the second transistor, and a drain voltage of the second input transistor is supplied to a gate of a third transistor of the second amplifier.