METHOD OF PRODUCING A SWITCHED-CAPACITOR AMPLIFIER INSENSITIVE TO CAPACITOR RATIO AND AMPLIFIER OFFSET

摘要

The invention relates to a method of producing a switched-capacitor amplifier that is insensitive to the capacitor ratio and the offset of the amplifiers. The inventive method comprises the use of four clock phases and two operational amplifiers in a switched capacitor circuit, such that, after the first two clock phases, an estimate of the error produced by capacitor decoupling is saved. Subsequently, during the two remaining clock phases, the aforementioned error is fed back in order to produce an amplification with gain independent of the capacitor ratio and the offset of the operational amplifiers. The circuit used to implement the inventive method comprises two operational amplifiers (or transconductance amplifiers) and three capacitors, one of which is used to save the error. The invention also relates to the method used to release an operational amplifier during non-consecutive clock phases and to sample and retain the input signal without increasing power consumption.