Design Criteria of Low-Power Oscillators for Consumer-Grade MEMS Resonant Sensors

摘要: This paper discusses the constraints in design of circuits for microelectromechanical systems (MEMS) resonant sensors consumer applications, presents a novel integrated circuit implementation, and shows that this approach can be competitive with respect to mostly used capacitive readout. From perspective, it is shown how large equivalent resistance typical MEMS resonators, their operation close mechanical nonlinearity, effect feedthrough capacitances on oscillating loop constrain power requirements driving/readout electronics. As case study, accelerometer built an industrial process coupled suitably designed transimpedance amplifier low-power “hard limiter.” The performance terms linearity across measurement range (±8 g), minimum measurable acceleration (1 mg readout bandwidth 100 Hz), consumption (≈ μW per axis) comparable those state-of-the-art inertial sensors.