| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply device showing a so-called foldback current limiting drooping characteristics, without the need for adjustment operation, and enabling stable and quick detection of overcurrent. SOLUTION: In a power supply device whose output is controlled by a control IC3, a detection resistor 8 for detecting overcurrent is inserted and connected to the low side of a power supply output, and a reference voltage source 9 generated separately from the power supply output is connected to the lower stream end of the detection resistor 8 through two or more resistors 12 and 14 connected in series. The high side of the power supply output is connected to an inversion input terminal of a comparator 11 through a resistor 13 while the upper stream end of the detection resistor 8 is connected to a non-inversion input terminal. The output signal of the comparator 11 is fed back to the power supply control IC3 for overcurrent protection. COPYRIGHT: (C)2005,JPO&NCIPI
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