Content address memory circuit with redundant array and method for implementing the same

A content addressable memory circuit having a redundant array, comprising:

• a primary content addressable memory array for storing data, the primary content addressable memory array having a plurality of primary entries, the primary entries being addressable by a plurality of primary addresses that defines a primary address space, one primary address for each primary entry;
• a redundant content addressable memory array having a set of redundant entries, the redundant entries being addressable by a set of redundant addresses that defines a redundant address space, one redundant address for each redundant entry, wherein each redundant entry is configured to store data for a defective primary entry;
• one or more storage devices for storing the redundant addresses and the primary addresses of one or more defective primary entries, the one or more storage devices associating the primary addresses of the defective primary entries with the redundant addresses for mapping between the primary and redundant address spaces;
• a primary encoder coupled to receive one or more primary addresses from the primary content addressable memory array and outputting a selected primary address as a primary search result;
• and
• a redundant encoder coupled to receive one or more redundant addresses from the redundant content addressable memory array and outputting a selected redundant address as a redundant search result.

A method for providing a redundant array for a content addressable memory circuit, the content addressable memory circuit including a primary content addressable memory array and a primary encoder, the primary content addressable memory array having a plurality of primary entries for storing data according to a specified algorithm, the primary entries being addressable by a plurality of primary addresses that defines a primary address space, one primary address for each primary entry, the primary encoder outputting a selected primary address as a primary search result, the method comprising:

• providing a redundant content addressable memory array having a set of redundant entries, the redundant entries being addressable by a set of redundant addresses that defines a redundant address space, one redundant address for each redundant entry, wherein each redundant entry is configured to store data for a defective primary entry;
• storing the redundant addresses and the primary addresses of one or more defective primary entries in one or more storage devices, the one or more storage devices associating the primary addresses of the defective primary entries with the redundant addresses for between the primary and redundant address spaces;
• providing a redundant encoder coupled to receive one or more redundant addresses from the redundant content addressable memory array and outputting a selected redundant address as a redundant search result according to the specified algorithm.