Resistive damping of pulse-sensed capacitive position sensors

This paper analyzes the dynamics and associated sensitivity limitations of a differential capacitive sensing scheme to determine the position of an elastically supported plate. Short pulses are applied differentially to a sense capacitor and reference capacitor. The voltage that appears on their shared node during the sense pulse is proportional to the difference between the two capacitances. The pulses impart kinetic energy to the supported plate, and after the pulses are removed, the mechanical system undergoes oscillatory motion. This paper analyzes the electro-mechanical dynamics of both the sensing procedure and a proposed resistive damping method that permits effective damping even in vacuum