Flip-Around Level-Shifting For Switched-Capacitor Amplifiers to Improve the Closed-Loop Settling of Floating-Inverter Amplifiers

This paper proposes a technique to reduce the steady-state error and increase the settling speed of closed-loop switched-capacitor (SC) amplifiers using floating-inverter amplifiers. The proposed idea takes inspiration from flip-around sample-and-hold and capacitor stacking to realize the amplification with fast settling, while the steady-state error is reduced in a way similar to correlated-level-shifting (CLS). However, unlike CLS, which requires three phases, the proposed flip-around level-shifting requires only two clock phases and hence is highly efficient when used with dynamic amplifiers, like the floating inverter amplifier (FIA). We show that this technique has a much faster closed-loop settling than conventional SC amplifiers, resulting in significant power savings in the FIA. Simulation results of an SC amplifier designed in a 180nm process, with the proposed technique and that of a conventional SC amplifier with CLS, are shown to validate the claims.