Closed-loop topologies for electrostatic drive resonant pressure sensor

Closed-loop topology plays an important role in sustaining reliable oscillation for resonant pressure sensor. A hybrid model of a typical MEMS resonant pressure sensor, which is driven by electrostatic force and sensed by capacitance changes,was constructed to research the influence of closed loop topology. Four closed-loop topologies including self-oscillation, automatic gain controller, Phase-Locked Loop and self-oscillation with automatic gain controller,were employed in the hybrid model. Using a mixed signal simulation platform,performance simulation and comparison among different topologies was implemented in terms of startup capability, automatic frequency tracking performance, shock immunity and frequency stability. The results show that PLL loop has the best overall performance. MEMS ; resonant pressure sensor ; closed-loop topology ; frequency tracking; PLL.