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. 26, 1998
Filed:
Dec. 30, 1996
Allan D Crane, Rugby, GB;
Cegelec Controls Limited, Warwickshire, GB;
Abstract
To protect a switching device having a possible open-circuit failure condition, an arrangement is featured in which a thyristor is connected in parallel with the main current-carrying terminals of the switching device to be protected. The thyristor is connected so that the forward current direction of the thyristor is the same as the normal current direction through the main terminals of the switching device. The arrangement provides for the thyristor to present an irreversible effective short-circuit when its normal parameter ratings are exceeded. The protection arrangement is particularly suitable for insulated-gate bipolar transistors (IGBT's) and preferably employs a pressure-packaged asymmetrical thyristor (ASCR) as the protection thyristor. The ASCR should be selected to withstand the normal (snubber-limited) dV/dt of the voltage across the switching device.