| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power source circuit suppressing power loss due to a starting resistor, and shortening the starting time. SOLUTION: A capacitor C2 is charged by a series circuit comprising a starting resistor R1 and a field effect transistor FET1. When the capacitor C2 is charged, a control integrated circuit IC1 outputs a signal so that a transistor TR1 is turned on/off, based on the charging voltage. The transistor TR1 executes switching based on the output signal. When voltage is generated in an auxiliary winding wire Nc, the voltage generated in the auxiliary winding wire Nc is detected by resistors R3 and R4. A transistor TR2 makes the field effect transistor FET1 turn to an off state, based on voltage generated on both ends of the resistor R4.
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