A High-Temperature-Stability MEMS Resonant Accelerometer Using a Ring-Down Driving Scheme With Active Ripple Suppression

Abstract

The temperature field across MEMS resonant accelerometers exhibits nonuniform and dynamic distributions under practical operating conditions, which makes temperature monitoring and thermal drift compensation in silicon accelerometers challenging. The ring-down driving scheme enables real-time quality factor monitoring for accurate in-situ temperature measurement, while frequency ripple induced by the amplitude-stiffening (A-S) effect degrades frequency stability. Addressing this problem, we propose a ring-down driving scheme with active ripple suppression (ARS), where the real-time monitored quality factor serves as a virtual thermometer, and the resonant frequency ripple is suppressed through electrostatic stiffness modulation. During continuous ring-down operation, the amplitude of the sensing signal is utilized as a phase stamp to continuously adjust the bias voltage of the driving signal via the dual-LUT and employ a calibration circuit based on P-type iterative learning control (ILC) to calibrate the feedback compensation relationship. The results of the experiment demonstrate that the proposed technique reduced the peak-to-peak frequency ripple from 7.3 Hz to 0.8 Hz, a suppression of 89% and achieved a harmonic suppression ratio of 41.9 dB, representing an improvement of $18.8\times $ . The proposed technique in generalization experiments achieved an average harmonic suppression ratio of 36.1 dB with a standard deviation of 5.4 dB. Additionally, it enables near in-situ temperature monitoring with low hysteresis, with a temperature resolution better than 0.2 °C within 1 Hz bandwidth through quality measurement. For applications of resonant accelerometers, the proposed ARS method achieves an acceleration resolution of 2.3 mg within a 10 Hz bandwidth and a bias stability of 1.0 mg after temperature compensation over the temperature range of 0 °C to 45 °C. The proposed system enables both real-time and accurate in-situ temperature tracking while improving acceleration resolution.[2026-0068]