Piezoelectric actuator driver circuit

Abstract

In a piezoelectric actuator driver circuit, a resistor provided to detect current is inserted in a current path for a piezoelectric actuator. A signal of a decreased voltage of the resistor is subjected to positive feedback to an amplifier circuit via a band-pass filter. An output signal of the amplifier circuit is subjected to negative feedback to the amplifier circuit via a band-elimination filter. The band-pass filter allows a signal of a fundamental resonant frequency of a piezoelectric device, which includes the piezoelectric actuator, to pass therethrough, and the band-elimination filter blocks the signal of the fundamental resonant frequency. Thus, a loop gain at a higher-order resonant frequency with respect to the fundamental resonant frequency becomes very low and a higher-order resonant mode can be effectively suppressed.

Dependencies are inferred from the claim text.