Abstract：
This paper presents an implementation scheme and experimental evaluation of a high-linearity closed-loop capacitive accelerometer based on ring-diode capacitance detection. By deducing the capacitance detection model of the ring-diode considering the influence of the diode, the existing theoretical model error of the ring-diode is corrected and a closed-loop scheme of reusing the detection electrode and the control electrode of the MEMS die is designed to apply this detection scheme to the parallel-plate accelerometer, which only has three independent electrodes. After analyzing the non-linear problems in the existing closed-loop control schemes, a theoretically absolute linear closed-loop control scheme is proposed, and an integrated closed-loop accelerometer is realized by combining the closed-loop diode detection. The experimental results of the ring-diode detection model are in agreement with the theoretical formula. The non-linearity of the accelerometer within ±1 g after the closed-loop is 130 ppm, compared with 1500 ppm when the open-loop is used.
摘要：
本文提出了一种基于环形二极管电容检测的高线性闭环电容加速度计的实现方案和实验评估。通过推导考虑二极管影响的环形二极管电容检测模型,校正了现有的环形二极管的理论模型误差，并设计了重用MEMS芯片的检测电极和控制电极的闭环方案，将该检测方案应用于平行板加速度计，只有三个独立的电极。在分析了现有闭环控制方案中存在的非线性问题后,提出了一种理论上绝对的线性闭环控制方案，结合闭环二极管检测实现了集成的闭环加速度计。环形二极管检测模型的实验结果与理论公式一致。闭环后±1g内加速度计的非线性度为130ppm，与使用开环时的1500ppm相比。
