Patent ID: 8164588

Claim:
A MEMS actuator comprising: a pixel comprising: a voltage bias, a variable gap capacitor having first and second terminals, said variable gap capacitor's first terminal connected to said voltage bias, and a switch having first and second terminals, said switch's first terminal connected in series with said variable gap capacitor's second terminal, said voltage bias providing a constant bias to the variable gap capacitor via said variable gap capacitor's first terminal, the variable gap capacitor having a movable plate and a fixed plate separated by a variable gap responsive to a charge modulation applied to the variable gap capacitor, and the switch for beginning an actuation cycle when closed and ending the actuation cycle when opened; and a charge integration circuit coupled to said switch's second terminal and configured to modulate charge on the variable gap capacitor during the actuation cycle, said charge integration circuit comprising: a capacitor, an operational amplifier, and a comparator, said capacitor for collecting charge flowing from said variable gap capacitor to the charge integration circuit during the actuation cycle, the operational amplifier coupled to the capacitor and arranged to provide an output voltage corresponding to the charge collected by said capacitor, and the comparator arranged to compare a predetermined voltage with the output voltage from said operational amplifier and to produce an output signal that indicates when the output voltage from said operational amplifier equals the predetermined voltage, said comparator's output signal arranged to trigger said switch to open and end said actuation cycle; wherein initiation of the actuation cycle triggers the flow of charge from the variable gap capacitor to the charge integration circuit.