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:
Oct. 30, 1984
Filed:
Jun. 21, 1982
James R Jaeschke, Waukesha, WI (US);
Eaton Corporation, Cleveland, OH (US);
Abstract
A dual mode power transistor circuit is provided for optimizing ON state dissipation, base drive requirements, and switching speed in applications subject to large overload currents for short periods of time. The circuit has dual modes or regions of operation: (1) rated current and below; and (2) overload current. In the overload region, additional base drive is supplied to the bipolar power transistor while also keeping such transistor in its active region, out of saturation, to enable fast turn-off. The additional base drive is supplied at a given sensed current-induced threshold voltage and enables the transistor to conduct increased collector current therethrough, which in turn reduces the otherwise increased collector to emitter voltage. Turn-off power dissipation is substantially reduced, in spite of the increased collector current, due to the drastically reduced collector to emitter voltage. Particularly simple dual mode Darlington-like transistor circuitry is disclosed. Bidirectional dual mode transistor circuitry is also disclosed.