DIRECT CURRENT POWER SUPPLY DEVICE

PURPOSE:To perform a stable start, by providing a dropping current setting circuit for setting two-stage, namely, large and small currents and a voltage lowering detecting circuit and setting the large current when the output voltage becomes a prescribed v alue or less and switching the set to the small current after a prescribed time. CONSTITUTION:An AC input 1 is filtered by a noise filter 2 and is rectified by an input rectifying circuit 3 and is interrupted in a high speed by a main switching circuit 4 and passes through a main transformer 5 and is rectified by an output rectifying circuit 6 and is smoothed by an output filter 7 to output a DC to a terminal 8. Just after supply of a load, a current larger than the rated current is flowed by the rush current of a capacitor, and the output voltage is lowered. This voltage is detected by a voltage detecting circuit 14; and when it is a prescribed value or more, a switching circuit 13 is driven to switch a dropping current setting circuit 12, and a current larger than he rated current is set through a controlling circuit 10 and a drive circuit 9, and the output voltage is raised gradually and is returned to the original state after the delay of a prescribed time. Thus, even if a device having a constant power inclination such as a DC-DC converter is connected, a stable start is performed without increasing the capacity of the power supply device.