基于等效电路法的微加速度计系统建模研究

讨论一类硅微闭环电容式加速度计系统级动态模型的建模过程与方法.MEMS（micro-electro-mechanical system）快速有效的系统级模拟依赖于准确简洁的器件宏模型的建立.文中首先针对一种基本机电换能器件进行研究,利用二元函数的Taylor公式,建立器件偏置点附近增量信号间的线性关系,进而建立可用等效电路形式描述的器件宏模型.以此为基础,分别探讨传感器中检测和加力两类差动电容模型的建立方法及其与外部环境的联接,得到可利用电路模拟软件进行分析的系统级等效电路.通过仿真实例验证模型的正确性,并简要讨论系统的主要动态特性.这些工作为进一步的系统仿真和全局优化提供可靠的模型基础.

RESEARCH ON A MICRO-ACCELEROMETER'S SYSTEMIC MODELING BASED ON EQUIVALENT CIRCUIT METHOD

An approach to establish the system-level dynamic model for a type of closed-loop capacitive micro-accelerometer is discussed. The work focuses on the macromodeling of a variable capacitor as an elementary electromechanical transducer at first. To get an equivalent circuit representatian of the model, the device is hnearized for incremental variables around its equilihrium point, using Taylor series expansion. Based on it, the macromodels of the two differential capacitors, which respectively serve as sense and force element in the sensor, are presented and coupled with outside components. Then, an example is illustrated and the validity of the proposed methodology is proved, The constructed system-level equivalent circuit, which can be analyzed by commercial circuit simulators, OrCAD etc., provides reliable foundation for further system simulation and global optimization for the prototype product.