具有空间连续行为的微型压力传感器系统级建模

Modeling of Capacitive Micro Pressure Sensor Featuring Space-Continuous Behavior

大多数MEMS器件(如梁、膜等)的动态特性方程为偏微分方程,因此建立对应组件的可重用参数化行为模型是一个难题.本文通过有限差分法把偏微分方程转化为常微分方程组,然后采用混合信号硬件描述语言进行描述,解决了该问题.针对电容式微型压力传感器,专门考虑膜片的空间连续行为以及结构、静电力的耦合作用,建立了包含接口电路在内的系统模型,据此进行了动态行为仿真.通过结果对比,验证了方法的实用性.相对于通用的参数化组件模型,当前MEMS商业化软件多采用逐个器件进行宏模型抽取的方式实现系统级建模和仿真.

A system-level modeling technique especially for space-continuous behavior is developed, inherently described using partial differential equations （PDEs）. Finite differences method （FDM） is used for discretization of PDEs. In this way, PDEs can be reduced to ordinary differential equations （ODE） for modeling, which is currently directly supported in analog and mixed-signal hardware description languages （HDL）. Using this method, the behavior equation of a capacitive micro pressure sensor is represented, then its reusable parameterized schematic-drive model is established coded by HDL （MAST）. A capacitive pressure sensor system including read-out circuitry is modeled, so the entire multi-domain micro-system can be simulated by Saber simulator. The introduced behavior model is verified by comparing the simulation results with FEA method.