Patent ID: 8035949

Claim:
A semiconductor device for controlling an electrostatic actuator having a first electrode and a second electrode formed such that they come close to each other when the electrostatic actuator is shifted from an open state to a closed state by electrostatic attraction against elastic force, the device comprising: a voltage generation unit generating, at least, as voltages to be applied between the first electrode and the second electrode, an operation voltage for shifting the electrostatic actuator from the open state to the closed state, a hold voltage equal to or lower than the operation voltage used for keeping the electrostatic actuator in the closed state, a monitor voltage lower than the hold voltage used for determining whether or not a charge to the first electrode or the second electrode is trapped thereto, and a separation voltage having characteristics opposite to those of the operation voltage for shifting the electrostatic actuator from the closed state to the open state; a capacitance detection unit detecting the capacitance between the first electrode and the second electrode; and a controller performing a control for applying a voltage generated by the voltage generation unit between the first electrode and the second electrode, the controller causing the capacitance detection unit to detect the capacitance between the first electrode and the second electrode, when the voltage between the first electrode and the second electrode is switched from the hold voltage to the monitor voltage for a certain period of time, whereas applying the separation voltage between the first electrode and the second electrode when the capacitance is equal to or larger than a certain value.