Design and Optimization of MEMS Vacuum Gauge Circuits for Enhanced Leakage Suppression and Accurate Capacitance Conversion

Micro-electro-mechanical systems (MEMS) capacitance diaphragm gauges (CDGs) integrate complementary metal-oxide-semiconductor (CMOS) technology, providing low cost, low power consumption, and high integration. However, their accuracy is limited by leakage currents that reduce capacitance-to-digital conversion precision. To overcome these limitations, this study presents a high-precision capacitance-to-digital conversion circuit. The circuit adopts a continuous-time switched-capacitor architecture and incorporates a calibration module to suppress leakage current effects and improve conversion accuracy. Simulation results indicate that the effects of leakage currents and circuit mismatches are suppressed to approximately 24% of their original level by the proposed design. Experimental validation further confirms that the circuit extends the measurement range below 0.1 torr, maintaining a correlation coefficient of 0.999, improved repeatability, and a root mean square error (RMSE) of 0.024 torr under constant pressure. These results improve both the accuracy and stability of MEMS CDG and lay a robust foundation for their deployment in high-precision vacuum measurement.