Patent ID: 9481166
Filing Date: 2016-11-01
CPC Classification: B41J,H01L

Claim Text:
1. A piezoelectric element drive circuit comprising: a drive unit that feedback-amplifies a drive signal for driving a piezoelectric element that uses negative voltage drive and outputs the resultant drive signal to an individual electrode of the piezoelectric element, the drive unit including an input amplification unit to which the drive signal is input, and an output boost unit in which two complementary transistors having different polarities are push-pull connected; a first power supply unit that supplies a first negative potential to the input amplification unit; a second power supply unit different from the first power supply unit, the second power supply unit supplying a second negative potential to the output boost unit; a first switch that switches the potential supplied to the input amplification unit from the first negative potential to a third negative potential having an absolute value smaller than that of the first negative potential; a second switch that blocks the supply of the second negative potential from the second power supply unit to the output boost unit; a third switch that connects the individual electrode of the piezoelectric element to a fourth negative potential via a first resistive element; and an input unit to which a control signal for switching between a drive mode in which driving of the piezoelectric element is performed and a state detection mode in which detection of a state of the piezoelectric element is performed is input, wherein in the drive mode, the potential supplied to the input amplification unit is set to the first negative potential, the second negative potential is supplied from the second power supply unit to the output boost unit, and the individual electrode of the piezoelectric element is not connected to the fourth negative potential via the first resistive element, and in the state detection mode, the potential supplied to the input amplification unit is set to the third negative potential, the supply of the second negative potential from the second power supply unit to the output boost unit is blocked, and the individual electrode of the piezoelectric element is connected to the fourth negative potential via the first resistive element.