Zero CVF input current switched-capacitor instrumentation amplifier

Most existing switched-capacitor amplifiers require current from the source to charge the input capacitor. This can cause errors when the source driving the amplifier has a large output resistance. In addition, nonideal parameters in opamps can cause errors. In the literature, circuits are found that can reduce the input current or reduce the errors of the opamp. However, none reduce both. This paper presents a new switched-capacitor amplifier topology that employs a pre-charge phase to reduce input current from the source and at the same time reduce errors due to the opamp. The design can be configured as a fully differential instrumentation amplifier with near infinite input resistance