| 摘要 |
<P>PROBLEM TO BE SOLVED: To discourage element breakage by accurately detecting occurrence of a dynamic avalanche (DA) phenomenon where a switching device flows a current while holding a voltage. <P>SOLUTION: An attention is focused on the fact that the fall time of a switching device 5 at turn off varies much depending on when DA phenomenon occurs and does not occur. A reactor 4 is connected in series, and its voltage across is measured with a signal measuring means 2 to detect a value corresponding to fall time. The time is measured at a time measuring circuit in an interface circuit 1. If the result is equal to a prescribed value or higher, the occurrence of the DA phenomenon is identified, for more accurate and quick detection of the DA phenomenon than before. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
