Patent ID: 8587181

Claim:
A piezo-electric actuator drive circuit for driving a piezo-electric actuator having multiple polarizing sections to which drive voltages are applied, comprising: multiple phase voltage pulse generating circuits, each of the phase voltage pulse generating circuit being associated with one of the polarizing sections and including: a voltage supply; a high-side switching element connected between the polarizing section and the voltage supply, for switching between a conductive state and a non-conductive state in response to a control signal; a low-side switching element connected between the polarizing section and ground potential, for switching between a conductive state and a non-conductive state in response to a control signal; and a switching element control circuit for outputting the control signals to the high-side switching element and the low-side switching element to control the high-side switching element and the low-side switching element to apply voltage pulse waveforms to the polarizing section by cyclically switching between a voltage-applied period during which the voltage supply is connected to the polarizing section with only the high-side switching element in a conductive state, a floating period during which the polarizing element is disconnected from the voltage supply and from ground potential with both the high-side switching element and the low-side switching element in a non-conductive state, and a grounded period during which the polarizing section is connected to ground potential with only the low-side switching element in a conductive state; wherein the multiple phase voltage pulse generating circuits apply voltage pulse waveforms with respectively differing phases to the multiple polarizing sections, and execute a first control mode in which voltage pulse waveforms including different floating periods are applied to each of the polarizing sections.