| 摘要 |
PURPOSE:To compensate assuredly offset voltage of a operation amplifier by operating the second switching circuit which synchronizes to the first switching circuit and is driven by switching. CONSTITUTION:When an input signal voltage VIN is impressed upon an input terminal 31, the offset voltage VOS of an operation amplifier 37 is outputted to an output terminal 38 when a clock signal phi2 is in the H level period. Then, an input signal voltage VIN is impressed upon the side which is connected with a switched capacitor circuit 36 when a clock signal phi1 is in the H level period. However, as mentioned above a condenser C12 holds the offset voltage VOS of the operation amplifier 37 as it has the charged voltage. Therefore, the voltages VIN - VOS are impressed upon the inversion input end (-) of the operation amplifier 37 after all, and the normal integration operation is executed. |
