Patent ID: 7347093
Filing Date: 2008-03-25
Classification: G01C

Abstract:
1. An angular velocity sensor comprising: an oscillating element including a drive electrode, a monitor electrode and a detecting electrode; a drive circuit having an output side connected with the drive electrode of the oscillating element; a detecting circuit having an input side connected with the detecting electrode of the oscillating element; a monitor circuit having an input side connected with the monitor electrode of the oscillating element; a rectifying circuit for rectifying an output signal of the monitor circuit; a smoothing circuit for smoothing an output signal of the rectifying circuit to obtain a smoothed signal; and an oscillation control circuit adapted to be fed with the output signal of the monitor circuit and to have a gain controlled with an output signal of the smoothing circuit, the oscillation control circuit inputting its output signal to the drive circuit, wherein the smoothing circuit includes: a first switch having an input terminal connected with the output side of the rectifying circuit; a first capacitor having a first terminal connected with an output terminal of the first switch; a second switch having an input terminal connected with the output terminal of the first switch and an output terminal connected with an input side of the oscillation control circuit; a first reference voltage connected with a second terminal of the first capacitor; a second capacitor having a first terminal connected with the output terminal of the second switch and a second terminal connected with the first reference voltage; and control signal feeding means for feeding a signal to control the ON/OFF of the first switch and the second switch.