| 摘要 |
The present invention makes it possible to detect overheating of an entire case without having to mount a specialized temperature detection IC. According to the present invention, control ICs (11-16) that control IGBTs (1-6) are provided with overheating detection comparators (31-36) that determine a chip overheating condition of the IGBTs (1-6), as well as with overheating detection comparators (51-56) that determine a case overheating condition. The output of the overheating detection comparators (51-56) is input to an AND circuit (71), and if all the overheating detection comparators (51-56) determine the presence of the case overheating condition, the AND circuit (71) outputs a high-level protection operation signal, and an alarm output circuit outputs an alarm signal. Since the chip overheating condition and case overheating condition are detected on the basis of the chip temperature obtained by means of temperature detection diodes (1a-6a) formed in each of the IGBTs (1-6), a temperature detection IC for case overheating protection is rendered unnecessary, and detection accuracy for case overheating is improved. |
