Patent ID: 7471029
Filing Date: 2008-12-30
Classification: H02N

Abstract:
1. A frequency-control-type piezo actuator driving circuit comprising: a piezo actuator that is driven by a constant amplitude of driving voltage pulse; a piezo driver that is connected to the piezo actuator so as to drive the piezo actuator; a frequency controller that is connected to the piezo driver so as to measure currents consumed when the piezo driver drives the piezo actuator, to detect a frequency corresponding to the maximum current among the measured currents, and to generate a frequency control signal corresponding to the detected frequency; and a frequency synthesizer that fixes a frequency of the piezo actuator in accordance with the frequency control signal of the frequency controller and generates the fixed frequency to the piezo driver; wherein the piezo driver includes: a pulse generator that generates a voltage pulse with the fixed frequency; a first driver stage that receives the voltage pulse of the pulse generator and buffers the voltage pulse to output; and a second driver stage that converts the voltage pulse, buffered and output by the first driver stage, into a current pulse to output to the piezo actuator.