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. 09, 1994
Filed:
Aug. 07, 1992
Peter H Sorrells, Chandler, AZ (US);
Ned D Garinger, Tempe, AZ (US);
VLSI Technology, Inc., San Jose, CA (US);
Abstract
An output pad for an integrated circuit includes circuitry to fix the output delay to a constant value even when changes occur in power supply voltage, manufacturing process and temperature. This output pad has a closed-loop feedback circuit which controls the delay of the output signal through an Adjustable Output Driver. A Fixed Delay Element provides a reference delay that does not change with induced variations. The loop adjusts the delay of the Adjustable Output Driver until the edge of the signal delayed by the Adjustable Output Driver is coincident with the edge of the signal delayed by the Fixed Delay Element within a defined tolerance. In a second embodiment the output pad has a Variable Delay Element with programmable delay values that remain constant over induced variations. In a third embodiment the Fixed Delay Element is deleted, and the delayed signal through the Adjustable Output Driver is compared to and therefore synchronized with a Reference Signal, which may be provided on-chip or from a source external to the chip.