| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a drive circuit of a piezoelectric element which eliminates the noise of the piezoelectric element connected to the drive circuit, and which suppresses output voltage ripples at the primary stage of a booster circuit which boosts power voltage, by reducing the higher harmonic waves of the output, without power loss due to the insertion of a resistor, etc. <P>SOLUTION: The drive circuit of the piezoelectric element 1 charges and discharges the piezoelectric element 1 with an output voltage of half-sine wave waveform, generated based on the reference voltage of the half-sine wave waveform by the booster circuit 2 which boosts the power voltage. The circuit is provided with a switching element 21 for controlling the boosting operation of the booster circuit 2 by an on/off operation; and a switching element control circuit 8 which on/off-controls the switching element 21, based on output obtained by comparing feedback voltage in the output of the booster circuit 2 with the reference voltage. When the feedback voltage is not higher than the reference voltage, the switching element control circuit 8 controls the on operation time of the switching element 21 at first time, subsequently, to be shorter than that at the second time and thereafter. <P>COPYRIGHT: (C)2008,JPO&INPIT |
