| 摘要 |
PROBLEM TO BE SOLVED: To reduce ringing that appears in an output voltage during startup. SOLUTION: When an IG switch 3 is turned on, a signal control circuit 24 changes a control signal Sd from H to L after a delay time Td and changes a switching signal S1 from L to H. The delay time Td is set to the time required to reduce the ringing superimposed on a battery voltage VB. Thus, a reference current I1 of a constant current circuit 25a flows in a resistance R4 and a current Ivb assumes a current value of I1xR4/R1 under control of a comparator 21 for limiting the currents. Thereafter, switching signals S2, S3, S4 are stepwise changed from L to H every period of time T and the limited current value increases in steps. Accordingly, an output voltage Vo rises gradually. COPYRIGHT: (C)2004,JPO
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