A gain stage and offset volage elimination method

摘要

A gain stage and offset voltage elimination method. The gain stage includes an amplifier, condensors and a number of switches. The switches are arranged to discharge the condensors and then charge the condensors to the offset voltage during an initialize period. When an input voltage is applied to the gain stage, the condensors do not act as capacitive loads for the amplifier. The gain stage can thus more quickly charge the condensors since the charging speed is approximately equal to the slew rate of the amplifier. The period for initializing the gain stage can be shortened while minimizing the current consumed.