| 摘要 |
PROBLEM TO BE SOLVED: To perform current limiting even in a region having a relatively low voltage. SOLUTION: In order to switch on, off drive current Id to a load 11 by the on or off operation of a drive switch (power MOSFET) 12, if a voltage Vds between the drain and the source of the drive switch 12 exceeds a predetermined threshold value, the current Id flowing to the drive switch 12 is limited. In addition, if the voltage Vds between the drain and the source of at least the drive switch 12 is less than the predetermined threshold value, the current imparted from a power source side to the drive switch 12 is branched by a branch circuit 45. Its overcurrent I1 is detected by using a current mirror circuit 43 and a constant current source 44. The current Id flowing to the drive switch 12 is limited based on its detected result. COPYRIGHT: (C)2004,JPO&NCIPI
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