Patent ID: 8319395
Filing Date: 2012-11-27
Classification: G03G

Abstract:
1. A power supply device comprising: an oscillator configured to output a clock signal; a pulse output unit configured to output a pulse by dividing a frequency of the clock signal in accordance with a control signal; a switching element driven by the pulse; a piezoelectric transformer configured to output a high alternating current voltage from a secondary side thereof when a voltage is intermittently applied to a primary side thereof by the switching element; a rectifier configured to convert the high alternating current voltage to a high direct current voltage; an output voltage conversion unit configured to convert the high direct current voltage to a low direct current voltage; a target setter configured to set and output a target signal; and a comparison unit configured to compare the low direct current voltage with the target signal and to output a comparison result, wherein a frequency division ratio of the pulse is controlled according to the comparison result, and thereby is changed so as to obtain the target signal.