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:
Nov. 04, 1997
Filed:
Jan. 19, 1996
Robert J Stoddard, Lincoln, MA (US);
Daniel P Orange, II, Worcester, MA (US);
Roger C Peppiette, Colinton, GB;
Allegro MicroSystems, Inc., Worcester, MA (US);
Abstract
A bipolar driver circuit includes a primary driver transistor and an independently controlled pre-driver transistor having an emitter connected to the base of the primary driver transistor and a collector connected to the collector of the primary driver transistor. In one embodiment, the collector of the primary driver transistor is connected to the output terminal of the driver circuit for sinking current from a load and, in another embodiment, the emitter of the primary driver transistor is connected to the output terminal of the driver circuit for sourcing current to a load. A first current source is connected to the base of the primary driver transistor and a second current source is connected to the base of the pre-driver transistor. The current sources are commonly controllable by an input signal. Also provided is an inverse conduction prevention circuit for preventing the pre-driver transistor from diverting base current from the primary driver transistor in the sink driver embodiment.