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:
Aug. 25, 1987
Filed:
May. 19, 1986
Randall C Gray, Tempe, AZ (US);
Robert M Hess, Roselle, IL (US);
Robert B Jarrett, Tempe, AZ (US);
Edward E Li, Roselle, IL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
An improved comparator circuit of the type which includes first and second differential PNP transistors operating in conjunction with a current mirror circuit includes an additional dual collector PNP transistor. That is, while the reference voltage is applied to the base of one of the differential transistors, the input voltage to be compared with the reference voltage applied to the emitter of the dual collector's transistor which has a first collector coupled to the base of the other differential transistor. The second collector is coupled to the base of the additional transistor. In this manner, should the input voltage fall below the substrate voltage, the additional transistor will be reverse biased thus preventing the parasitic diode at the base of the second differential transistor from turning on.