Method and apparatus for redundant location addressing using data compression

• US 20050099875A1
• Filed: 12/07/2004
• Published: 05/12/2005
• Est. Priority Date: 01/22/1998
• Status: Active Grant

• Current Assignee: Thomas W. Voshell
• Original Assignee: Thomas W. Voshell
• Inventors: Voshell, Thomas W.
• Granted Patent: US 7,346,818 B2
• Time in Patent Office: Days
• US Class Current: 365/230.03
• CPC Class Codes: G06F 12/02 Addressing or allocation; Relocation program address sequencing G06F9/00; arrangements for selecting an address in a digital store G11C8/00
• CPC Class Codes: G11C 29/44 Indication or identification of errors, e.g. for repair
• CPC Class Codes: G11C 29/76 using address translation or modifications

Abstract

A method and apparatus for identifying defective cells in a memory array includes receiving a request for accessing an address and analyzing the address to determine when the address matches an address stored in a temporary memory array. When the address does not match any address stored in the temporary memory array, a wait instruction is sent to a processor and the address is analyzed to determine which portion of compressed data stored in a map memory array to decompress. The map memory array stores data containing compressed addresses of defective cells in a first memory array. The portion of compressed data is then decompressed to provide expanded data when the address does not match any address stored in the temporary memory array. The expanded data are then written to the temporary memory array, and the expanded data are compared to the address to determine when the address corresponds to an expanded datum of the expanded data.

Claims

1. A method for identifying defective cells in a memory array, the method comprising steps of:

receiving a memory test command;

initiating a memory test in response to the memory test command, the memory test for determining addresses of defective cells in a random-access memory;

concluding the memory test; and

compressing the addresses of defective cells to provide compressed address data.

2-40. -40. (canceled)