Patent ID: 6137363
Filing Date: 2000-10-24
Classification: H03F

Abstract:
An operational amplifier comprising:an inverting input terminal;a non-inverting input terminal;an output terminal;a differential amplifying circuit comprising a pair of input transistors having control terminals connected to said inverting input terminal and said non-inverting input terminal, respectively;an output circuit connected to said differential amplifying circuit for amplifying an output signal of said differential amplifying circuit and for providing an amplified output to said output terminal;wherein said input transistors are bipolar transistors having base terminals serving as said control terminals; andother transistors provided in said operational amplifier, the other transistors being MOS transistors;wherein said differential amplifying circuit comprises first and second MOS transistors cooperatively forming a current mirror circuit, said first MOS transistor produces a first terminal potential responsive to a voltage applied to said inverting input terminal and said second MOS transistor produces a second terminal potential responsive to a voltage applied to said non-inverting input terminal;wherein said output is responsive to a difference between said first terminal potential and said second terminal potential; andwherein said first and second MOS transistors are N-channel MOS transistors that are associated with P-channel MOS transistors having gate terminals connected to output terminals of said input transistors.