Switched Capacitor Amplifier

Abstract

To provide a switched capacitor amplifier which can perform highly accurate output even if an input range and an output range of an operational amplifier are different from each other.SOLUTION: An SC amplifier 1 of a whole difference construction, comprises: an operational amplifier 2 of a differential output type; capacitors Cs1 and Cs2 in which a first terminal is connected to an input terminal of the operational amplifier 2; capacitors Cf1 and Cf2 which are connected to between an input terminal and an output terminal of the operational amplifier 2; capacitors Cd1 and Cd2 in which the first terminal is connected to the input terminal of the operational amplifier 2 while enabling an accumulation of an electric charge corresponded to a DAC voltage output from a D / A converter; and a CMFB circuit 3 which controls a same phase level of an output voltage of the operational amplifier 2. A common potential of an input of the operational amplifier 2 is a common potential VCMIN, and the common potential of the output of the operational amplifier 2, the common potential of a bias of the CMFB circuit 3, and the common potential of a second terminal side of the capacitors Cf1 and Cf2 is a common potential VCMO which is generated by a circuit and is different from the common potential VCMIN.SELECTED DRAWING: Figure 1

Images