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:
Dec. 02, 2008
Filed:
Aug. 15, 2007
Dragos Cartina, Burnaby, CA;
Dragos Cartina, Burnaby, CA;
PMC-Sierra, Inc., Santa Clara, CA (US);
Abstract
A method and apparatus are provided for calibrating a multi-stage A/D converter, such as a pipelined A/D converter. The method and apparatus are based on estimating the bounds of histograms of codes from various stages in the A/D converter. Known approaches were effective in calibrating A/D converters but during bound estimation suffered from lock-up conditions from which it could not recover. Embodiments of the present invention describe two mechanisms for recovering from lock-up conditions and a mechanism for fast locking. If neither a gross lock-up condition nor a fine lock-up condition is detected, the estimated bound is modified based on a comparison of a current digital residue with a fast lock value and a bound window. A discontinuity in the transfer characteristic of the A/D converter can then be removed based on the estimated bound.