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:
Sep. 24, 1996
Filed:
Apr. 19, 1995
Alan R Desroches, San Jose, CA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A flexible and efficient integrated circuit chip that includes pad drivers for driving an impedance of a transmission line, wherein the integrated circuit further includes all additional circuitry to automatically adjust a matching impedance of the pad drivers. The integrated circuit chip includes a set of selectively activatable pad drivers and a counter coupled with the drivers for selectively activating an initial number of members of the set of the pad drivers to drive the transmission line with a test pulse. The integrated circuit chip further includes a comparator having a first input for sensing a voltage amplitude of the test pulse and a second input coupled with a voltage reference for comparing the voltage amplitude of the test pulse with the reference voltage. An output of the comparator is coupled with the counter for increasing the counter's initial number of selected members of the set of the pad drivers if the voltage amplitude of the test pulse is less than the reference voltage. Such iterative capabilities of the invention provide an automatic optimal selection of the pad drivers, so that the parallel impedance of the activated drivers provides a good match with the impedance of the transmission line.