| 摘要 |
PROBLEM TO BE SOLVED: To prevent the parts of a switching power supply from excessively heating when the switching power supply is connected to an electronic transformer. SOLUTION: The switching power supply is so designed as to convert an input voltage into a desired voltage and output it. If a control portion 130 detects that the input voltage has not reached a predetermined voltage when operation of a switching element is started, the control portion controls the operation of a driving portion 142 and causes it to stop the operation of the switching element in the switching element portion 143. Before the driving of the switching element is started, the output voltage of the electronic transformer is low. Therefore, when the switching power supply is connected to the electronic transformer, it is not driven, and its parts are prevented from excessively heating. When the switching power supply is connected to an AC outlet, the input voltage reaches the predetermined voltage. Therefore, the switching power supply can be properly operated. COPYRIGHT: (C)2004,JPO&NCIPI
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