Patent ID: 8554101
Filing Date: 2013-10-08
Classification: G03G,H02M

Abstract:
1. A power supply apparatus comprising: a pulse generation unit that generates a pulse signal; a piezoelectric transformer that outputs a voltage according to a frequency of the pulse signal generated by the pulse generation unit; a control unit that controls the frequency of the pulse signal; a voltage detection unit that detects a plurality of voltages that are output from the piezoelectric transformer; a peak value detection unit that detects a plurality of peak values in the output voltages of the piezoelectric transformer according to a plurality of frequencies of the pulse signal; an identification unit that identifies a frequency corresponding to the highest peak value of the plurality of peak values detected by the peak value detection unit, and a frequency corresponding to a next peak value next to and on a higher- or lower-frequency side of the frequency corresponding to the highest peak value; and a setting unit that sets an initial frequency of the pulse signal that is used to cause the output voltage of the piezoelectric transformer to approach a target voltage, within a frequency range between the frequency corresponding to the highest peak value and the frequency corresponding to the next peak value identified by the identification unit, wherein the control unit further controls the pulse generation unit so that, when causing the output voltage of the piezoelectric transformer to approach the target voltage, the frequency of the pulse signal generated by the pulse generation unit is changed from the initial frequency set by the setting unit.