| 摘要 |
PURPOSE:To decrease the number of power terminals and to facilitate IC-implementation by using only one power source for operational amplification as a power source. CONSTITUTION:A switched capacitor circuit 70 switches a switching capacitor CS to the 1st contacts a1 and a2, or the 2nd contacts b1 and b2 through changeover switches S1 and S2 which operate at the same time. The contact a1 is connected to an input terminal 71 applied with an input voltage Vi, and the contact a2 is connected to the inverted input terminal of an operational amplifier 31; and the contacts b1 and b2 are connected together to a power source VDD. The amplifier 31 is applied with a power voltage VDD and an earth potential voltage GN, and its output terminal is connected to an output terminal 72 and also connected to the inverted input terminal through a capacitor Cf. Further, a bias circuit applies the uninverted input terminal with an intermediate voltage between the potential VDD and potential GND. Thus, only the single power source circuit is managed with. |
