A 3-axis accelerometer and strain sensor system for building integrity monitoring

An Ultra-Low-Power readout architecture for capacitive MEMS-based accelerometers and strain sensors is presented. The system can read both accelerometers and strain sensors in a half-bridge configuration. An accurate VerilogA model of the sensor was made to improve simulations. The gain of the system is controlled by integrating pulses from the excitation circuit allowing accurate control of the Signal-to-Noise ratio. A Figure-of-Merit of 4.41 × 10−20 F√(W/Hz) was achieved for a sensor range of ±2.0 g and ±20,000 μɛ over a 100 Hz bandwidth. A minimum of 440 nW power consumption was recorded. Residual motion artifacts are also cancelled by the system.