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. 04, 1999
Filed:
Mar. 18, 1997
Thomas A Somerville, Tempe, AZ (US);
Robert L Vyne, Tempe, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A bandgap reference circuit (60) provides a selectable bandgap reference voltage that is substantially insensitive to temperature variations of an operating reference circuit. A final curvature caused by a current (I.sub.2) in a temperature coefficient compensation transistor (40) is equal to a drift in a Vbe voltage of a transistor (18) having a negative temperature coefficient plus the drift in a Vbe voltage of a transistor (20) having a positive temperature coefficient minus the drift in a Vbe voltage of the temperature coefficient compensation transistor (40). The nonlinearity of the current (I.sub.2) in the temperature coefficient compensation transistor (40) is adjusted by selecting a compensating current and associated temperature coefficient for the compensating current (I.sub.0) to minimize the characteristic bow or curvature of the current (I.sub.2) in the temperature coefficient compensation transistor (40).