Bipolar Electrostatic Driving of Isolated Micro-Resonator for Sensing High Voltage of Battery Output with Resolution

Electrostatic Si resonator was applied to sense the voltage at the facing electrode in a highly isolated approach. The resonant frequency shifts under the effect of the electrical field from the facing electrode connected to the high voltage (corresponding to the battery). Here, two resonators are fabricated. The electrical isolation was obtained by driving the resonators to be floated electrically. The charging of the resonator causes the fluctuation of the driving performance, degrading the sensing resolution. The driving voltage was set to be bipolar to avoid the fluctuation. This novel method stabilizes the resonant frequency realizing 0.25 V accuracy against 80 V. Feasibility for measuring the voltage up to 420 V is demonstrated.