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:
Mar. 01, 1988
Filed:
Feb. 09, 1987
Ralph D Jessee, Shawnee Township, Allen County, OH (US);
Joseph M Urish, Shawnee Township, Allen County, OH (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
A transistor drive circuit includes a driver transistor and a power switching transistor connected in a Darlington configuration which receives turn-on and turn-off signals from a drive transformer. A capacitor is provided for connection between the driver transistor base and the switching transistor emitter during a turn-off period such that the voltage on the capacitor hastens turn-off of the driver transistor and the switching transistor. A diode connected between the emitter and the base of the driver transistor provides for continuing current flow from the capacitor following turn-off of the driver transistor but prior to turn-off of the switching transistor. After the switching transistor has turned off, the capacitor is recharged prior to the presence of a turn-on signal from the drive transformer.