Electrostatic anti-spring-enhanced MEMS accelerometer with auto-tuning capability

This study introduces a MEMS accelerometer equipped with an adaptive tuning system for an electrostatic anti-spring. As the input acceleration increases, the sensitivity of the adaptive MEMS accelerometer decreases to compensate for the measurement range. It leverages the benefits of both conventional open- and closed-loop accelerometer designs. Comprehensive theoretical analyses and experimental tests are conducted, showing consistency between theory and experimental results. In comparison to conventional MEMS accelerometer designs, this novel MEMS accelerometer demonstrates enhanced performance. With an actuation voltage of 15.4 V and under 0 g acceleration input, the sensitivity of the accelerometer improves from 1.28 V/g to 39.43 V/g, and the spring constant is reduced from 41.0 N/m to 1.38 N/m. The noise floor also decreases from 8628 ng/√Hz (at 100 Hz) to 279 ng/√Hz (at 100 Hz). The dynamic range enhances from 127 dB to 157 dB. Besides, a hybrid continuous-time interface is utilized to apply the actuation force on the sensing comb fingers. This approach not only simplifies the circuit design but also minimizes the required die area, power consumption. The combination of these features makes the novel MEMS accelerometer both highly sensitive and large measurement range, as a promising solution for various applications.