| 摘要 |
PROBLEM TO BE SOLVED: To provide an overcurrent protection device for MOS transistor(TR) that can obtain stable operating characteristics, independently of a temperature change. SOLUTION: An operational amplifier circuit 31 calculates a difference between output voltages of 1st and 2nd constant voltage circuits 12, 40, provides an output of a voltage Vref2 corresponding to the difference, and a comparator circuit 34 compares the output voltage Vref2 from the operational amplifier circuit 31 with a terminal voltage Vs of a sensing resistor Rs connected to a source of a current mirror MOS TR 13. Then a control circuit 50 corrects the control voltage given to the gates of a load driving MOS TR 11 and the current mirror MOS TR 13, on the basis of the result of comparison by the comparator circuit. Thus, the current mirror type overcurrent protection device can reduce the effect of a temperature onto an overcurrent detecting current caused by a temperature coefficient of an ON-resistance of the MOS TRs.
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