Patent ID: 7436261

Claim:
An operational amplifier, comprising: a differential amplifier circuit configured to receive an inverting input voltage (VIN−) and a non-inverting input voltage (VIN+); and an auxiliary circuit for improving a slew rate of an output voltage of the differential amplifier circuit, wherein when a voltage difference between the inverting input voltage (VIN−) and the non-inverting input voltage (VIN+) is less than a predetermined small voltage difference, an output terminal of the auxiliary circuit is disconnected from an output terminal of the differential amplifier circuit, and when the voltage difference between the inverting input voltage (VIN−) and the non-inverting input voltage (VIN+) exceeds the predetermined small voltage difference so that a voltage waveform is shifted to at least one direction, the voltage shift is accelerated by receiving/transferring a current from/to the output terminal of the differential amplifier circuit toward a shifting direction of an output voltage of the differential amplifier circuit.