Cosimulation and Optimization of Constant Temperature Circuit for Thermistor-Based MEMS Vacuum Sensors

Thermistor-based microelectromechanical system (MEMS) vacuum sensors are widely used for vacuum monitoring. It is usually operated in constant temperature (CT) mode because this mode is more suited for rough vacuum regime and could avoid potential damage caused by overheating. However, the CT circuit will suffer from temperature drift, it is necessary to compare and optimize existing temperature drift suppression methods. In this study, the thermal equivalent circuit method is used to set up the macro-model of thermistor-based MEMS vacuum sensors; the co-simulation with three CT circuits is carried out and compared using Advanced Design System software; and an optimized temperature drift suppression CT circuit is designed. Experiment results got by the optimized temperature drift suppression CT circuit show that the average error between simulation and experiment in response voltage for the vacuum pressure range of 3.75×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> to more than 1000 Torr is 3.003 %, and the response voltage at atmospheric pressure and at 3.75×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> Torr are separately ±0.694 % and ±2.949 % when the ambient temperature ranges from -20 °C to 80 °C.