To drive a capacitive load efficiently over a long period by using a high precision voltage waveform.
Voltages of a plurality of steps, separated from each other by a voltage corresponding to a voltage between terminals of a charge storage element, are generated by charging a plurality of charge storage elements from a power supply through a backflow prevention means and switching a connection state between the charge storage elements by using voltage generation switches, where at least one voltage generation switch is provided for each charge storage element. An electric load is driven by supplying the voltage thus generated through a voltage application switch. Voltage of the charge storage element is regulated by disconnecting the application switch during a predetermined period where the applied voltage does not change even during driving of the electric load, and then switching the connection state of a plurality of voltage generation switches. Since the capacitive load holds the applied voltage even if the application switch is disconnected, the precision of the voltage waveform is maintained over a long period by regulating the voltage of the charge storage element while the applied voltage is held.
OSHIMA ATSUSHI
MIYAZAKI SHINICHI
TABATA KUNIO
IDE NORITAKA
Osamu Suzawa
Kazuhiko Miyasaka