Patent ID: 8630104
Filing Date: 2014-01-14
Classification: H02M,Y02B

Abstract:
1. A switching power supply into which AC power is input and which outputs DC power electrically insulated from the AC power, the switching power supply comprising: a first rectification-smoothing unit that rectifies and smooths the AC power; an insulation transformer that includes at least a primary winding, a secondary winding, and a third winding; a second rectification-smoothing unit which is connected to the secondary winding, rectifies and smooths AC power from the secondary winding and outputs DC power; a first switching device that is connected between a DC-side terminal of the first rectification-smoothing unit and the primary winding; an inrush current suppressing unit which is connected to the primary winding in parallel therewith and which includes a second switching device; a charge storing unit that is connected to a DC side of the first rectification-smoothing unit; a third switching device that is connected in series to the DC side of the first rectification-smoothing unit so as to prevent the charge storing unit from discharging; a charging circuit that charges the charge storing unit with power from the third winding in a boosted manner; a fourth switching device which is connected between the charging circuit and the charge storing unit and which controls a charging current of the charging circuit; a power factor improving control unit which controls the first, second, third and fourth switching devices and which improves a power factor of the AC power to be input; and a power-suspension detecting unit that detects a power suspension of the AC power, the third switching device being controlled when the power-suspension detecting unit detects a power suspension of the AC power in order to cause the charge storing unit that stores a charge in advance to discharge the insulated DC power to an output side through the insulation transformer.