A Digital Readout Approach for Differential Capacitive Pressure Sensor

An approach providing a digital output linearly proportional to capacitance difference for capacitive pressure sensor is presented. Based on sigma-delta (ΣΔ) technique, the structure is insensitive to circuit imperfections and component mismatch, permitting the realization of digitized capacitive sensor readout with good accuracy. Analysis shows that a resolution as high as 20 bits is achievable. Simulation results are given to confirm the effectiveness.