A dual frequency range integrated circuit accelerometer using capacitive and piezoelectric sensing techniques

An architecture for a silicon accelerometer is presented where two separate sensing techniques use a single micromachined cantilever beam. The accelerometer is capable of measuring over a range of /spl plusmn/10 G, with a resolution of 100 /spl mu/G from DC to 300 Hz. Accelerations from DC to 0.25 Hz are measured by a capacitive sensor, while a piezoelectric sensor measures accelerations from 0.1 Hz to 300 Hz. The piezoelectric sensor is auto-zeroed in order to minimize the effects of charge leakage. The system is calibrated as a function of acceleration magnitude to reduce first-order nonlinearities.<>