Patent ID: 8193861
Filing Date: 2012-06-05
Classification: H03F

Abstract:
1. A differential amplifier, comprising: a non-inverting input terminal; an inverting input terminal; an output terminal; a first differential amplifier circuit including a differential input circuit including N-type MOS transistors connected to the non-inverting input terminal and the inverting input terminal; a second differential amplifier circuit including a differential input circuit including P-type MOS transistors connected to the non-inverting input terminal and the inverting input terminal; and an output circuit which is connected to the first differential amplifier circuit and the second differential amplifier circuit and includes an output transistor, wherein the P-type MOS transistors of the second differential amplifier serve as a current source of the first differential amplifier circuit and comprise a current control circuit in which a constant current value is changed by a voltage of the non-inverting input terminal, and, when the voltage of the non-inverting input terminal changes, a current flowing into the output transistor is maintained to a constant value.