Column redundancy for content addressable memory
AssigneeMosaid Technologies Incorporated
InventorPeter Vlasenko
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Abstract
A system for adding redundancy to the data path of a content addressable memory array is disclosed herein. The disclosed system employs an array of memory elements, supplemented by an array of redundant memory elements, with a switching system and a redundancy control system to ensure that defective memory elements are not accessed. Additionally a pull down unit is employed on the search lines of non-operative memory elements to ensure that inaccurate search results are not reported.
Claims6
A content addressable memory having a column redundancy system for replacing defective memory elements with redundant memory elements, said content addressable memory being segmented into a plurality of memory arrays, each of said memory arrays comprising:
- a plurality of columns of memory elements;
- a predetermined number of redundant columns of memory elements;
- a local search data path comprising a plurality of local search data lines coupled to said columns of memory elements;
- a local read/write data path comprising a plurality of local read/write data lines coupled to said memory elements;
- a redundancy control block;
- and
- a switching block for selectively coupling said local search data path and said local read/write data path to respective global search data path and global read/write data path in response to control signals provided by said redundancy control block, said switching block switching global data destined for an associated local data path to an adjacent local data path in the event a defective column is detected.
Dependencies are inferred from the claim text.