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. 17, 2019
Filed:
Aug. 21, 2018
Xilinx, Inc., San Jose, CA (US);
Chin Yang Koay, Singapore, SG;
Hongyuan Zhao, Singapore, SG;
Siok Wei Lim, Singapore, SG;
Kee Hian Tan, Singapore, SG;
XILINX, INC., San Jose, CA (US);
Abstract
Apparatus and associated methods relate to a programmable resistor having a resistance iteratively programmed by a calibration control loop. In an illustrative example, the calibration control loop may alternately sample the programmable resistance and a reference resistance by producing a corresponding voltage drop across the resistors. The voltage drops may, for example, be induced by the same constant current source. The calibration control loop may compare the voltage drops with a comparator, for example. In some examples, the comparator may provide a count direction signal to a logic block, generating a calibration code. The calibration code may, for example, be applied to the programmable resistor, such that the resistance of the programmable resistor iteratively approaches the resistance of the reference resistor. Various programmable resistors within a calibration control loop may, for example, substantially improve termination impedances of high-speed transmission lines and may mitigate random resistive mismatch variations.