Patent ID: 9224536
Filing Date: 2015-12-29
Classification: H01G,H03J

Abstract:
1. A variable capacitance device comprising: a fixed plate including a first driving electrode and a first variable capacitance electrode; a movable plate including a second driving electrode facing the first driving electrode and a second variable capacitance electrode facing the first variable capacitance electrode; a driving voltage applying unit that applies a driving voltage between the first driving electrode and the second driving electrode; a reference capacitor having a predetermined capacitance; a capacitance detection signal generation unit that applies a capacitance detection pulse signal to a driving capacitance portion including the first driving electrode and the second driving electrode and to the reference capacitor; and a voltage change comparator that compares a voltage change of the driving capacitance portion and a voltage change of the reference capacitor caused by the capacitance detection pulse signal and outputs a comparison result; wherein the driving voltage applying unit controls the driving voltage based on the comparison result.