The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 20, 1997
Filed:
Sep. 19, 1994
Naoki Sakurai, Hitachi, JP;
Yoshitaka Sugawara, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A circuit connecting a sub-IGBT element S.sub.2 having a smaller current capacity and a smaller saturated current than the main IGBT element S.sub.1 and a resistance R.sub.1 in series is connected to the main IGBT element S.sub.1 in parallel, a MOSFET element S.sub.3 being connected between the gate electrode of the sub-IGBT element S.sub.2 and the emitter electrode of the main IGBT element S.sub.1, a delay element being connected between the gate electrode of the sub-IGBT element S.sub.2 and the gate electrode of the main IGBT element S.sub.1. In normal operation, the ON-state voltage is small and low loss can be realized. In the event of a short-circuit accident, the sub-IGBT element S.sub.2 detects the short-circuit before the main IGBT element S.sub.1 turns on to prevent an over-current from flowing in the main IGBT element S.sub.1, which substantially improves the short-circuit resistivity of the semiconductor device.