Patent · US Expired

Content addressable memory

US6496398B2 · kind B2 · utility

5Cited by

10References

11Claims

0Family size

Assignee

International Business Machines Corporation · US

Inventors

Gerhard Hellner · Lenggries, DE
Rolf Sautter · Nagold, DE
Otto Wagner · Edenkoben, DE

Key dates

Filing date	Dec 6, 2001
Grant date	Dec 17, 2002
Priority date	—
Expiry date	Dec 6, 2021

Classification

Technology area (CPC G)Physics
CPC primaryG11C15/04
WIPO fieldComputer technology
WIPO sectorElectrical engineering

Abstract

The present invention relates to content addressable memory (CAM), particularly, to a CAM having its memory array, which contains a plurality of memory locations, being divided into at least a first and a second memory block (100, 102), whereby the first and second memory block (100, 102) are formed by a first and second portion of each of said memory locations, respectively. The CAM further comprises a first set of compare lines (115) and a first set-of match lines (116) associated to said first memory block (100), and a second set of compare lines (117) and a second set of match lines (118) associated to said second memory block (102), and pre-charge units (112, 114) for charging said match lines before a comparison operation. The present invention provides an improved CAM which allows flagging of memory locations of which the content only partially matches a given comparison value. This is achieved by a CAM according to the above features using the pre-charge state of the match lines (116, 118) as a logically valid state.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.