基于Sigma-Delta技术的差分电容检测电路设计

Differential capacitance detection circuit design based on the sigma-delta technology

接口电路是悬浮转子微陀螺研制中的关键技术之一。本文对静电悬浮转子微陀螺的差分电容结构建立其简化数学模型,并结合Sigma-Delta技术的优点提出了一种新颖的闭环检测电路。该检测电路能够直接输出数字信号,系统稳定性好,对陀螺失效具有自检特性并且能够有效避免陀螺的锁住。与通常采用的调制解调方法相比,该检测电路大大节省了器件,因此非常适用于对微陀螺原型进行测试评估。对该检测电路的仿真结果表明,其灵敏度为2V/g,动态范围约为1g。

The interface circuit is one of the key technology in the design of electrostatically suspended gyroscope .In this paper a simplified mathematic model for the differential capaci- tive structure of the electrostatically suspended gyroscope is presented, and combines the advantage of the sigma-delta modulation, a novel close-loop detection circuit is designed. This detection circuit could direct output digital signal, has a inherent self-test feature and could prevent the latch up of the micro gyroscope. Compared to the common used modulation method, the detection circuit is low in component count, which makes it particularly suitable for prototype evaluation. Simulation result shows that the detection circuit has a sensitivity of 2Wg and a dynamic measurement range of approximately 1g.