| 摘要 |
A switching power source apparatus is provided to reduce a loss in a starting circuit and a switching device during an intermittent on/off operation of the switching device. A switching power source apparatus includes a switching device, a control circuit(3), a starting circuit, a first rectifying-smoothing circuit(CC1), and a second rectifying-smoothing circuit. The switching device is connected to a current power through a first winding wire of a transformer. The control circuit controls an on/off operation of the switching device. The starting circuit provides a power voltage to the control circuit and provides a starting current to the control circuit. The first rectifying-smoothing circuit rectifies and smoothes a voltage generated by a secondary winding wire of the transformer into an output voltage, and provides the output voltage to a load. The second rectifying-smoothing circuit rectifies and smoothes a voltage generated by a third winding wire of the transformer into a power voltage provided to the control. The starting circuit provides a first starting current generated by a DC power. If the device starts, the starting circuit cuts off the first starting current. After the device starts, if the power voltage of the control circuit is lowered into a turn-off power, the starting circuit provides a second starting current which is smaller than the first starting current. If the power voltage of the control circuit is lowered to a predetermined lower voltage than the power voltage, the starting circuit provides the first starting current.
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