| 摘要 |
PROBLEM TO BE SOLVED: To provide an overcurrent protection circuit achieving overcurrent protection without being affected by ambient temperature. SOLUTION: The overcurrent protection circuit 30 is structured by integrating: a resistor R1 for detecting an output current using a parasitic resistance component of a metal wiring connected to a power transistor 10; a first current mirror circuit, which includes a pair of bipolar transistors Q1, Q2, in which a voltage across the resistor R1 is supplied between the emitters of each transistor; a second current mirror circuit (N0, N1, N2), which maintains the collector currents I1, I2 of the transistors Q1, Q2 to a predetermined mirror ratio; and a switch N3, which is turned on and off according to a collector voltage V2 of the transistor and from one end of which an overcurrent protection signal OCP is drawn. COPYRIGHT: (C)2009,JPO&INPIT
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