| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply circuit capable of assuring the power source of an integrated circuit even under an overload or in short circuit. SOLUTION: The power supply circuit is provided with a flyback type auxiliary power supply circuit 1 in which a power supply circuit transformer T is provided with an auxiliary coil NS, one end of which is connected to the cathode of a first rectifier diode D1. The other end of the auxiliary coil NS is connected to an integrated circuit 4 through a second rectifier diode D2. A circuit 2 for detecting an overload or short circuit is connected to the other end of the auxiliary coil NS. The detection circuit 2 is provided with a first switch element Tr1. A third rectifier diode D3 is connected to one end of the auxiliary coil NS. The third rectifier diode D3 is connected to a trigger circuit 3 that supplies power to the integrated circuit 4 when the detection circuit 2 detects the overload, etc. The trigger circuit 3 is provided with a second switch element Tr2. The integrated circuit 4 is connected to the emitter of the second switch element Tr2 through a fourth rectifier diode D4. COPYRIGHT: (C)2004,JPO
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