Patent ID: 8149559

Claim:
A piezoelectric actuator driving device comprising: an inductor connected in series with a piezoelectric actuator; a charging path for supplying power from a positive side of a direct current power supply to a series circuit of the inductor and the piezoelectric actuator through a charging switch; a discharging path connected in parallel with the series circuit for discharging charged electric charges of the piezoelectric actuator through a discharging switch; a first diode connected in parallel with the charging switch so that a cathode thereof is connected on a positive side of the direct current power supply; a second diode connected in parallel with the discharging switch so that an anode thereof is connected on a negative side of the direct current power supply; a charge/discharge controlling means for carrying out charging switching control to repeatedly turn on and off the charging switch with the discharging switch kept OFF and thereby charging and expanding the piezoelectric actuator when a drive command is externally inputted, and for carrying out discharging switching control to repeatedly turn on and off the discharging switch with the charging switch kept OFF and thereby discharging and contracting the piezoelectric actuator when a drive stop command is externally inputted, wherein the charge/discharge controlling means is configured to turn on the discharging switch in a period from when the discharging switching control is terminated to when the charging switching control is started next; a selector switch, connected between the piezoelectric actuator on the opposite side to the inductor and the negative side of the direct current power supply, for selecting the piezoelectric actuator as an object to be driven; and a third diode connected in parallel with the selector switch so that an anode thereof is connected to the negative side of the direct current power supply circuit, wherein the charge/discharge controlling means turns on the selector switch in carrying out the charging switching control and the discharging switching control to drive the piezoelectric actuator and turns off the selector switch when the discharging switch is ON during the period from when the discharging switching control is terminated to when the charging switching control is started next.