| 摘要 |
PURPOSE:To omit an overcurrent protection circuit, by setting an auxiliary power section, and by feeding the electrical energy of a condenser charged from an input side through a resistor, to a drive control circuit section. CONSTITUTION:So far as a switching power supply apparatus is concerned, when a condenser 22 is charged through a resistor 21 in an auxiliary power source section 13 from a DC power source, then voltage Ec at both the ends of the condenser 22 is heightened, and the input of the voltage Ec to a Schmidt circuit 23 is provided. The Schmidt circuit 23 is turned ON when input voltage is E1, and is turned OFF when it is E3, and a switch circuit 24 is set in a switching state, and via a drive control circuit 12, a switching circuit 11 is driven. Then, DC voltage E0 is converted to single phase alternating current, and the output is directed to a load 16 through a transformer 14, a rectifier circuit 15, and the like. The transformer 14 is provided with a third winding 25, and the condenser 22 is charged with the partial output through a rectifier circuit 26. As a result, automatic protecting function can be kept on the power supply apparatus.
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