Murata Manufacturing Co., Ltd.

Yamaha Corporation

Hidekazu Ono

Nobuaki H Tsuji

Tatsuya Kishii

Tsuyoshi Okami

Takashi Mizota

Hideyo Haruhana

Takayuki Yoshida

A vibrator drive circuit is configured to drive a vibrator massin a prescribed vibration direction. The vibrator drive circuit includes a drive unit configured to drive a vibrator based on a reference signal SGof a predetermined frequency to cause the vibrator to vibrate in a vibration direction, a phase detector configured to detect a vibration waveform of the vibrator in the vibration direction and to output an output voltage Vcnt in accordance with a phase difference between reference signal SGand a vibration waveform thereof, and two capacitors each formed of a movable electrode provided in the vibrator and a fixed electrode provided to face the movable electrode, the output voltage Vcnt being applied to the fixed electrode. The phase detector is configured to adjust the output voltage Vcnt in accordance with the phase difference, thereby changing electrostatic force in each of the capacitors for controlling the phase difference to be 90 degrees.

Vibrator drive circuit

A power supply control circuit includes a mode controlling unit which, in accordance with an output voltage of an amplifying section, performs a mode up for switching a current power supply voltage of the amplifying section to a higher power supply voltage being higher than the current power supply voltage, and which, in a case where a magnitude of the output voltage of the amplifying section is smaller than a threshold voltage for a predetermined time period or longer, performs a mode down for switching the power supply voltage of the amplifying section to a lower power supply voltage being lower than the current power supply voltage, and a threshold setting unit which sets the threshold voltage based on the output voltage of the amplifying section at a timing when the mode up is performed.

Power supply control circuit

Growing community of inventors

Hamamatsu, Japan

Hidekazu Ono