Operationally amplifying method and operational amplifier

摘要

An operational amplifier circuit including a differential amplifier circuit and a current mirror circuit. The differential amplifier circuit amplifies a signal which enters a non-inverted input terminal and an inverted input terminal. The differential amplifier circuit receives resulting differential currents from an inverted current inflow terminal and a non-inverted current inflow terminal, and outputs corresponding differential currents from an inverted current outflow terminal and an non-inverted current outflow terminal to the current mirror circuit. The differential current flowing in the terminal is converted into a voltage by a load transistor so that the voltage drives a p-channel transistor, whereas the corresponding differential current flowing out from the terminal is converted into a voltage by a load transistor so that the voltage drives an n-channel transistor.