A novel very low-voltage SC-CMFB technique for fully-differential reset-opamp circuits

This paper proposes a novel switched-capacitor (SC) common-mode feedback (CMFB) technique that can be efficiently applied to very low-voltage reset-opamp architectures. The proposed CMFB circuit utilizes the inherent differential-pair existing in the opamps as the virtual ground common-mode voltage detector, thus providing a new approach for very low-voltage implementation of fully-differential opamps (instead of traditional two single-ended opamps operating in pseudo-differential mode) using traditional reset-opamps techniques, such that half of the opamps power can be saved. Simulations with real switches and a fully-differential opamp in 1-V supply voltage are provided to verify the effectiveness of the proposed technique.