Design and Simulation of a Readout Circuit for Capacitive Sensing in CMOS-MEMS Devices

Many electronic devices have started to pay attention to CMOS-MEMS technology which provides many advantages. Mostly used in accelerometer and gyroscopes, CMOS-MEMS provides a lot of challenges including the sensing of the output signal. While the signal is about femto- (10-15) to atto- (10-18) farad, the noise presence in the signal is also another constraint. One of the method in sensing the signal is Capacitive Sensing which utilize the difference of the capacitance and distance produced between the comb fingers of capacitances. The front-end circuit is very crucial in producing clean signal and free from noises. This paper use voltage sensing technique of the front-end circuit to evaluate the signal. The evaluation is done by using two techniques; circuit simulation by using MultiSim software, and mathematical modeling by using MATLAB. The result obtained shows that the circuit with Chopper Stabilization technique used has much better output than the circuit without the technique used.