Secondary sense loop with force feedback capability

A secondary loop comprising:

• a secondary element of at least one mechanical resonator of a MEMS gyroscope;
• an analog front end circuitry configured to receive an analog detection signal from the secondary element and to provide an analog secondary input signal;
• a digital secondary loop circuitry;
• and
• an analog back end circuitry, wherein said digital secondary loop circuitry comprises:
• a signal path receiving at its input the analog secondary input signal representing a detection motion of the mechanical resonator and providing at its output an output signal indicating an angular velocity of said MEMS gyroscope is subject to, the signal path comprising an analog-to-digital converter configured to digitize the analog secondary input signal into a digitized secondary signal and a digital low pass infinite impulse response filter;
• and
• a digital force feedback circuitry configured to produce a force feedback signal for stabilizing operation of the secondary loop, wherein a response function of the digital secondary loop circuitry is adjusted by the force feedback signal so that the derivative of the phase response of the digital secondary loop circuitry at frequencies around a resonance frequency of the at least one mechanical resonator is reduced, said digital force feedback circuitry comprising:
• the analog-to-digital converter common with the signal path;
• the digital low pass infinite impulse response filter common with the signal path, the digital low pass infinite impulse response filter being configured to receive at its input the digitized secondary signal, to cause a −90-degree phase shift to the digitized secondary signal at the resonance frequency, and to provide in its output a phase shifted digitized secondary signal;
• and
• a digital-to-analog converter configured to convert the phase shifted digitized secondary signal into an analog force feedback signal to be fed back towards the secondary element of the MEMS gyroscope by the analog back end circuitry, the analog force feedback signal causing a damping force against movements of the secondary element.