Patent ID: 8682197

Claim:
A high voltage power supplying apparatus comprising: a signal generation unit which generates a drive signal with a predetermined frequency; a piezoelectric transformer which outputs a voltage in accordance with a frequency of the drive signal; a detection unit which detects an output voltage of said piezoelectric transformer; and a control unit which controls said signal generation unit to change the frequency of the drive signal so that an output voltage of said piezoelectric transformer becomes a target voltage, wherein said control unit is configured to change the frequency of the drive signal by a first predetermined value until an output voltage of the piezoelectric transformer is greater than a target voltage or the output voltage of the piezoelectric transformer is smaller than the target voltage, and to further change the frequency of the drive signal by a second predetermined value, smaller than the first predetermined value, after the output voltage is greater than the target voltage or the output voltage is smaller than the target voltage.