A power supply equipment includes a plurality of units each including a capacitor and an isolated DC-DC converter connected between the both terminals of the capacitor, wherein DC input sides of the plurality of units are connected in series and the DC output sides are connected together in parallel. The DC power supply equipment also comprises control circuits to control the isolated DC-DC converters. The control circuits generate operation commands to operate some of the plurality of units in an alternating sequence with a same time ratio in a predetermined control period in a light load condition, and the control circuits control the isolated DC-DC converters of the units according to the operation command.