To provide a piezoelectric actuator driver which can determine the failure of a piezoelectric actuator 9 and a drive signal amplifier circuit 4, and can protect the piezoelectric actuator 9 from an applied abnormal voltage in the failure.
The piezoelectric actuator driver includes a failure determination unit 11 which estimates a voltage and a current applied to a piezoelectric actuator 9 based on a drive signal generated in a drive signal generator 1, and determines the failure of the piezoelectric actuator 9 and a drive signal amplifier circuit 4 by comparing the estimated voltage and current with a detected voltage in a voltage detection circuit 8 and a detected current in a current detection circuit 10, and a switchover determination circuit 16 which switches over the voltage supplied to the piezoelectric actuator 9 from the drive signal amplifier circuit 4 depending on the determining the result. The switchover determination circuit 16 can protect the piezoelectric actuator 9 from the applied abnormal voltage in the failure by interrupting the voltage supplied to the piezoelectric actuator 9 from the drive signal amplifier circuit 4 when the failure is determined by the failure determination unit 11.
ITO OSAMU
KASHIWAGI YASUHIRO
Konobu Kato