Fully-Differential Offset-Cancelling Circuit with Configurable Output Common-Mode Voltage

Abstract

For certain applications, the offset voltage of the amplifiers represents a problem that must be addressed, since it may affect the transfer characteristics of the system. Offset memorization techniques allow to partially cancel the offset voltage either at the input or at the output of an amplifier, but their effectiveness is highly dependent on the amplifier gain. For this reason, these techniques do not result in a complete offset cancellation when used with low-gain amplifiers. In this work, a fully-differential offset-cancelling circuit based on offset memorization techniques is introduced along with its analysis and simulation results. Among the features of the proposed circuit are a configurable output common-mode voltage and a complete offset cancellation even when used with low-gain amplifiers.