| 摘要 |
PROBLEM TO BE SOLVED: To provide an excess current protecting apparatus capable of reducing a loss in load short-circuit, wherein defective start-up hardly occurs even on a capacitive load. SOLUTION: An output voltage rise detection CMP25 detects that an output voltage VOUT reaches to a detection reference voltage level V1 and shifts a latch circuit 29 from a reset state after turning on a power to a set state. When the latch circuit 29 becomes a set state and an excessive current switch voltage detection CMP27 detects that the output voltage VOUT becomes lower than a switch reference voltage level V2, An AND circuit 30 controls a constant current source 24 to cut it off, lowers a detection level of a voltage at both ends of a resistance 16 corresponding to an excess current detected by an excess current detection AMP21, and lowers an excess current detection level. When a power is on, the latch circuit 29 becomes a reset state, so that the constant current source 24 operates at a constant current and the excess current detection level is heightened to prevent defective start-up. COPYRIGHT: (C)2004,JPO&NCIPI
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