Patent ID: 8497791
Filing Date: 2013-07-30
Classification: H03F

Abstract:
1. An operational amplifier circuit comprising: a first input terminal and an output terminal; an operational amplifier having an inverting input terminal and a non-inverting input terminal; a first input resistance circuit that is disposed between the first input terminal and the inverting input terminal of the operational amplifier; and a feedback resistance circuit that is disposed between the output terminal and the inverting input terminal of the operational amplifier, wherein the non-inverting input terminal of the operational amplifier is connected to a reference potential, wherein the first input resistance circuit has a first resistor and a second resistor including a MOS transistor, which are different in temperature coefficient from each other, connected in series with each other, wherein the feedback resistor circuit has a third resistor and a fourth resistor including a MOS transistor, which are different in temperature coefficient from each other, connected in series with each other, wherein a source-drain path of the MOS transistor of the second resistor is disposed between the first resistor and the inverting input terminal of the operational amplifier, wherein a source-drain path of the MOS transistor of the fourth resistor is disposed between the third resistor and the inverting input terminal of the operational amplifier, and wherein substrate potentials of the MOS transistors of the second resistor and the fourth resistor are set to a potential of the inverting input terminal of the operational amplifier.