Circuit and method to detect faults of a MEMS device including an oscillating mass

A circuit for detecting faults in a MicroElectroMechanical System (MEMS) device that includes a periodically oscillating mass, comprising:

• an input configured to receive a position signal formed by a succession of samples of an analog signal that is a function of a position of the periodically oscillating mass, said position signal having an amplitude and an oscillation frequency, said amplitude being directly proportional to an oscillation amplitude of the periodically oscillating mass of the MEMS device;
• a reference circuit configured to generate a first reference signal formed by successions of samples of a first sinusoidal signal and generate a second reference signal formed by successions of samples of a second sinusoidal signal, wherein the first and second sinusoidal signals having a frequency equal to the oscillation frequency and are phase-shifted with respect to one another by 90°;
• a first multiplier configured to multiply the position signal by the first reference signal to generate a first product signal;
• a second multiplier configured to multiply the position signal by the second reference signal to generate a second product signal;
• a first lowpass filter configured to filter the first product signal and generate a first filtered signal;
• a second lowpass filter configured to filter the second product signal and generate a second filtered signal;
• an estimator circuit configured to generate estimates of said amplitude as a function of the first and second filtered signals;
• and
• a decision circuit configured to perform a comparison of the estimates of said amplitude with a range of values to detect the presence of faults in the periodic oscillation of the mass of the MEMS device.