| 摘要 |
PURPOSE: To provide a power supply apparatus which reduces the pulsation of an output voltage and attenuates the harmonics of an input current and to provide a discharge-lamp lighting apparatus and a lighting fixture. CONSTITUTION: A power supply apparatus is provided with a rectifier device 4 which rectifies the output voltage of an AC power supply 1, with a first switching device 5 and a second switching device 6 installed in series at output terminals of the rectifier device and which are turned on and off alternately, with a series circuit, by a first capacitor 8 and an inductor 7, which is installed across the switching device on one side and which performs a smoothing action with reference to the output frequency of the rectifier device and with a second capacitor 11 which forms a resonance circuit in coorporation with the inductor according to the ON-OFF operation of the switching devices as one pair and whose capacitance is smaller than that of the first capacitor 8. Consequently, by the action of a resonance voltage by the inductor and the second capacitor, an input current can be made to flow from the rectifier device over nearly the whole period of a rectified non-smoothed DC voltage, and the waveform of the input current is made close to sine waves so as to achieve a low distortion. |
