Rail-to-rail operation of very low voltage CMOS switched-capacitor circuits

A circuit that allows switch operation down to very low voltages in standard CMOS technologies is proposed. The circuit is an extension of the gate-source bootstrapping technique such that rail-to-rail operation of a single n-switch becomes possible. Architecture modifications introduced in a standard switched-capacitor circuit reduce the number of critical switches to only one switch per opamp plus one at the circuit input. Simulations show the usefulness of the proposed configuration down to 0.9 V.