Switched-capacitor circuits with reduced sensitivity to amplifier gain

A new technique for reducing the effect of finite amplifier gain in switched-capacitor circuits is described. The principle is to perform a preliminary charge transfer operation preceding every desired charge transfer operation, thus obtaining a close approximation of the finite gain error which is stored and subsequently used for correction. This provides excellent suppression of the finite gain effect, independent of the relationship between the clock rate and the signal frequencies. The technique is quite general in nature and can be applied in a wide variety of switchedcapacitor circuits. Its major applications will be in precision analog signal processing circuits like precision amplifiers, A/D and D/A converters, and analog arithmetic building blocks. Simulation studies indicate that this technique has the potential to reduce the amplifier gain requirements in such circuits by one to two orders of magnitude. This would simplify amplifier design and increase the high-frequency capability of these circuits.