| 摘要 |
<p>Disclosed is a short-circuit protection apparatus for semiconductor switch elements used at a high voltage, such as an IGBT. The short-circuit protection apparatus detects a short-circuit state easily with less possibility of malfunction, even if there is no current sensing switch element, and protects the semiconductor switch elements from breaking. The apparatus detects, as voltage information, the level of a current in the IGBT (1) wherein the current is being carried, on the basis of a divided voltage obtained by dividing the voltage on the collector side using a high resistor (2) and resistors (3, 4) for detection, then, the apparatus estimates power loss in the IGBT (1) on the basis of the voltage value, and estimates a heat value on the basis of the power loss. When the estimated heat value exceeds a predetermined value, the apparatus gradually reduces a gate signal voltage and protects the IGBT (1).</p> |
