Simultaneous Control of Dielectric Charge and Device Capacitance in Electrostatic MEMS

This letter presents a double closed loop for simultaneously controlling the net dielectric charge and the device capacitance in contactless electrostatic MEMS devices. The first loop controls the net charge trapped in the dielectric layer by continuously monitoring the horizontal displacement of the C-V characteristic and applying bipolar actuation voltages to keep such net charge at the target value. The second loop adapts the actuation voltages so that the measured capacitance matches a desired value while maintaining the primary control of charge.