| 摘要 |
PROBLEM TO BE SOLVED: To provide the protecting device of a semiconductor element capable of protecting the semiconductor element under the consideration of the temperature of the semiconductor element and the surrounding temperature. SOLUTION: This device is provided with a comparator CMP1 for comparing a voltage VDS between the drain and source of an FET(T1) with a predetermined decision voltage V4 and a means for interrupting the FET(T1) when it is decided that the voltage VDS between the drain and source is larger than the voltage V4 by the comparator CMP1. Then, the product of an on-resistance Ron when the channel temperature of the FET(T1) is the upper limit of an allowable temperature and the minimum current value when the channel temperature reaches the upper limit value of the allowable temperature according to autologous heating due to Joule's heat is defined as a critical voltage, and the decision voltage is set so as to be not more than the critical voltage. COPYRIGHT: (C)2004,JPO
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