Continuous Mode-Reversal FM Accelerometer With 60-g FSR, 10-μg/K Drift, and VRE Rejection
Christian Padovani, Riccardo Nastri, Leonardo Gaffuri Pagani, Paolo Frigerio, Francesco Rizzini, Giacomo Langfelder
Abstract
This work advances the research on continuous mode-reversal frequency modulated accelerometers by characterizing in depth some of their nonidealities, proposing methods for their compensation, and exploiting a renovated sensor design that enables closed-loop compensation of shock and vibrations. The scale factor nonlinearity is first investigated and compensated through a cubic calibration term, yielding a 50% larger range for a 2.5-fold larger scale factor than in former implementations. Additionally, temperature effects on the zero-g offset are compensated by exploiting the value of the low-pass filtered resonance frequency, which yields a valuable information of the silicon sensor temperature. This enables reducing the zero-g-offset temperature dependence by a factor 5 over previous works on similar structures. Finally, a closed-loop compensation of the quality factor, implemented through additional driving electrodes in the structure, guarantees a 25-fold reduction on effects of shocks and vibrations exciting the acceleration-sensitive mode. [2022-0117]