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:
May. 08, 2007
Filed:
Nov. 18, 2003
Tony K. Ngai, Saratoga, CA (US);
Jennifer Wong, Fremont, CA (US);
Wayson J. Lowe, Belmont, CA (US);
Xilinx, Inc., San Jose, CA (US);
Abstract
Programmable logic devices (PLDs) including self-repairing RAM circuits, and methods of automatically replacing defective columns in RAM arrays. A RAM circuit including redundant columns is tested during the PLD configuration sequence using a built in self test (BIST) procedure. If a defective column is detected, an error flag is stored in an associated volatile memory circuit. After the BIST procedure is complete, the PLD configuration process continues. The presence of the error flag causes the configuration data to bypass the defective column and to be passed directly into a replacement column. The configuration process continues until the remainder of the circuit is configured, including the redundant column. In other embodiments, the BIST procedure is initiated independently from the PLD configuration process. When a defective column is detected, user operation resumes with data being shunted from the defective column to a redundant column in a fashion transparent to the user.