Micromachined accelerometer and method with continuous self-testing

摘要

Micromachined accelerometer and method in which a proof mass is suspended above a substrate for movement in response to acceleration, electrodes form capacitors which change in capacitance in response to movement of the proof mass, processing circuitry responsive to the changes in capacitance provides an output signal corresponding to movement of the proof mass, a test signal is applied to the electrodes during use of the accelerometer to produce additional movement of the proof mass and a corresponding test signal component in the output signal, and the output signal is monitored to determine whether the accelerometer is operating normally by the presence of the test signal component in the output signal.