Switched-capacitor amplifier circuit

摘要

A switched-capacitor amplifier circuit (200 and 300) with rail-to-rail capability without requiring a rail-to-rail operational amplifier includes a switched-capacitor amplifier (202 and 302) and an input network (201) coupled to the switched-capacitor amplifier. The switched-capacitor amplifier includes a non-rail-to-rail operational amplifier (275 and 375). The input network prevents the non-rail-to-rail operational amplifier from receiving an input differential signal that has a common-mode voltage at or near rails of the non-rail-to-rail operational amplifier. Voltages at input terminals of the operational amplifier remain near analog ground, which is an arbitrary voltage level between the rails, during both phases of switching in the switched-capacitor amplifier. In one embodiment, the switched-capacitor amplifier uses a correlated double sampling technique.