Correlated-level-shifting and correlated-double-sampling switched-capacitor gain stages, systems implementing the gain stages, and methods of their operation

摘要

Embodiments of apparatus and methods for applying a gain to an input signal are provided. An embodiment of a switched-capacitor gain stage circuit includes an input node, an output node, an operational amplifier, a correlated-double-sampling portion, a correlated-level-shifting portion, and a switching configuration. The operational amplifier has a first amplifier input, a second amplifier input, and an amplifier output. The correlated-double-sampling portion includes a plurality of sampling capacitors arranged in parallel and selectively coupled between the input node and a central node, and an offset storage capacitor including a first terminal coupled to the first amplifier input. The correlated-level-shifting portion includes a correlated-level-shifting capacitor including a first terminal coupled to the output node. The switching configuration has multiple switches that are controllable sequentially to place the gain stage circuit in a sampling state, an approximate output voltage storage state, a level shifting and gain state, and an output state.