Patent ID: 8174200

Claim:
A piezoelectric transformer driving device, comprising: an oscillator configured to generate a clock signal; a frequency-divider configured to output a pulse by dividing the clock signal by a received frequency-divide ratio; a switching element configured to be driven by the pulse and to intermittently apply a voltage to a primary side of a piezoelectric transformer so as to output a high voltage alternating current from a secondary side of the piezoelectric transformer; a frequency-divide ratio instructing unit configured to hold a frequency-divide ratio instruction value of a real number having an integer part and a fractional part; a binarization unit configured to binarize the frequency-divide ratio instruction value into two different integer frequency-divide ratios α and β and to selectively output the frequency-divide ratios α or β, wherein the binarization unit adjusts an appearance ratio of the frequency-divide ratios α and β such that a fractional part of an average value per unit time of the frequency-divide ratio output from the binarization unit is equal to the fractional part of an average value per unit time of the frequency-divide ratio instruction value.