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:
Jun. 17, 1997
Filed:
Aug. 31, 1995
James K Azotea, Saratoga Springs, NY (US);
Harris Corporation, Melbourne, FL (US);
Abstract
A circuit and method for interrupting an AC load current includes a first MOS Controlled Thyristor (MCT) for selectively interrupting the load current. The current through the first MCT is reduced when the load current is to be interrupted by providing a pulse resonant commutation (PRC) current through the first MCT which flows in a direction opposed to the AC load current direction and which has a magnitude reducing the current through the first MCT to an MCT 'off' condition (e.g., when a voltage across the MCT is reversed, when there is near zero current through the MCT, or when a current is within the MCT's SOA.) The first MCT turns itself off when MCT gate voltage is an 'on' voltage and when reverse voltage is across the MCT. An MCT 'off' voltage may then be provided by sensing MCT current and providing an 'off' voltage to the MCT gate when the sensed current indicates that the MCT is an 'off' condition. The PRC current is generated by a second MCT which is triggered with a brief gate pulse when the load current is to be interrupted. The load current also may be sensed and the gate pulse triggered in the second MCT to interrupt the load current when the load current exceeds a predetermined value.