Dc power-supply device and refrigeration-cycle application device including the same

A DC power-supply device that converts an alternating current into a direct current and supplies the direct current to a load while having a reactor on a conversion path thereof, the DC power-supply device comprising:

• a first capacitor and a second capacitor serially connected between output terminals to the load;
• a charging unit to selectively charge one or both of the first capacitor and the second capacitor;
• and
• a control unit to control the charging unit to change a charging frequency based on a ratio, to a period obtained by combining a charging period and a non-charging period when a pair of the first capacitor and the second capacitor is charged, of the non-charging period, the charging frequency being, an inverse number of the period obtained by combining the charging period and the non-charging period, and thereby to control an output voltage to the load.