Capacitively coupled chopper instrumentation amplifier and control method thereof

A capacitively coupled chopper instrumentation amplifier, comprising:

• an input chopping unit, which is configured to operably chop a differential input signal based on a clock signal to generate a chopped differential input signal;
• a feedback chopping unit, which is configured to operably chop a differential output signal based on the clock signal to generate a chopped differential feedback signal;
• a capacitor feedback network, which includes a pair of differential input capacitors and a pair of differential feedback capacitors, wherein each of the differential input capacitors is connected to a corresponding of the differential feedback capacitors in series between the input chopping unit and the feedback chopping unit, wherein the input chopping unit, the feedback chopping unit, and the capacitor feedback network are coupled to convert a differential difference of the chopped differential output signal and the chopped differential input signal to generate a differential feedback signal by a switching capacitor voltage division method;
• and
• a fully differential amplifier, which is configured to operably amplify the differential feedback signal to generate the differential output signal;
• wherein a gain between the differential output signal and the differential input signal is equal to twice a differential input capacitance of the differential input capacitor divided by a differential feedback capacitance of the differential feedback capacitor;
• wherein during a normal operation, the gain is a predetermined gain, the differential input capacitance is a predetermined differential input capacitance, and the differential feedback capacitance is a predetermined differential feedback capacitance;
• wherein during an initial period, when the input chopping unit receives the differential input signal, the capacitively coupled chopper instrumentation amplifier avoids an output saturation of the capacitively coupled chopper instrumentation amplifier by reducing the gain to an adjusted gain.