| 摘要 |
PROBLEM TO BE SOLVED: To simply detect a short-circuited state to protect a semiconductor switch element from breakdown with a reduced possibility of malfunction, even without the presence of a current sensing switch element with respect to a short-circuit protector for semiconductor switch elements, such as IGBT, used with a high voltage. SOLUTION: The magnitude of the current of IGBT 1 in conduction is detected as voltage information from a voltage on the collector side by dividing a voltage via a high resistor 2 and detecting resistors 3, 4. Power loss at the IGBT 1 is estimated from this voltage value and an amount of heat is estimated based on this power loss. When the estimated amount of heat exceeds a predetermined value, a gate signal voltage is gradually reduced to protect the IGBT 1. COPYRIGHT: (C)2011,JPO&INPIT
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