HIGH RESOLUTION SIGMA DELTA MODULATOR FOR CAPACITANCE SENSOR TERMINAL DISPLACEMENT MEASUREMENT

摘要

A single plate capacitance sensor includes a sensor capacitor and a reference capacitor that share common plate. A capacitance-to-digital sigma delta modulator provides separate sensor excitation and reference excitation signals to the sensor capacitor and the reference capacitor to provide high resolution detection. Programmable ratio-metric excitation voltages and adaptive excitation voltage sources can be used to enhance modulator performance.