Patent ID: 7236047

Claim:
A band gap circuit that generates a reference voltage, comprising: a voltage generating circuit configured to generate a voltage having negative temperature dependency; a first switched-capacitor circuit including a first operational amplifier circuit having an input terminal and an output terminal; a first input capacitor that is connected to the input terminal of the first operational amplifier circuit; and a first feedback capacitor that is connected to the input terminal and the output terminal of the first operational amplifier circuit; a second switched-capacitor circuit including a second operational amplifier circuit having an input terminal and an output terminal; a second input capacitor that is connected to the input terminal of the second operational amplifier circuit; and a second feedback capacitor that is connected to the input terminal and the output terminal of the second operational amplifier circuit; and a first coupling capacitor that capacitively couples the output terminal of the second operational amplifier circuit with the input terminal of the first operational amplifier circuit, wherein a thermal voltage, which is a voltage proportional to absolute temperature, is multiplied by a coefficient, and a multiplied thermal voltage is added to the voltage generated by the voltage generating circuit, the coefficient being determined based on capacitances of the first input capacitor, the first feedback capacitor, the first coupling capacitor, the second input capacitor, and the second feedback capacitor, wherein the first coupling capacitor is configured to have a capacitance smaller than a capacitance of the first feedback capacitor.