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 representation of the model, the device is linearized for incremental variables around its equilibrium 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.