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. 05, 1991
Filed:
Jun. 04, 1990
Mavin C Swapp, Mesa, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
An ECL logic circuit having differential inputs and differential outputs and programmable propagation delay time is provided. The differential inputs are coupled to a first differential amplifier as is done on a conventional differential ECL circuit. A second feedback differential amplifier is coupled to the collectors of the first differential amplifier. Current in the first differential amplifier is normally constant, whereas current in the feedback differential amplifier can be programmably adjusted. By adjusting the current in the feedback differential amplifier the feedback differential amplifier loads the logic circuit forcing a voltage swing which is up to double that normally provided by the first differential amplifier, therefore increasing the time required for either output to change from a logic LOW to a logic HIGH. This delay results in a variable propagation delay which is controlled by adjusting current flow in the feedback differential amplifier.