| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply device that is dispensed with an auxiliary winding of a transformer, and can cope with the abrupt change of a load. SOLUTION: The switching power supply device 100 comprises: a MOSFET 4; the transformer 3; rectifying diodes 5a, 5b; an inductance element 6; and an output smoothing capacitor 7. The switching power supply device also comprises: a first control circuit 10 that controls the MOSFET 4; a starting power supply 12 that applies a DC voltage to the first control circuit 10 at starting; a self-bias circuit 16 that applies a DC voltage to the first control circuit 10 with an output voltage of the switching power supply device 100 as an input; a second control circuit 17 that drives the self-bias circuit 16; a current detection circuit 14 that detects a current flowing to the load; and an overcurrent protection circuit 15 that determines an overcurrent state. COPYRIGHT: (C)2006,JPO&NCIPI
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