Techniques for operating non-volatile memory systems with data sectors having different sizes than the sizes of the pages and/or blocks of the memory

• US 6,684,289 B1
• Filed: 11/22/2000
• Issued: 01/27/2004
• Est. Priority Date: 11/22/2000
• Status: Expired due to Term

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: SanDisk Corporation (Western Digital Corporation)
• Inventors: Gonzalez, Carlos, Harari, Eliyahou, Conley, Kevin M.
• Primary Examiner(s): PORTKA, GARY J
• Application Number:
  US09/718,802
• Time in Patent Office: 1,161 Days
• Field of Search: 365/235, 365/185.11, 711/103, 711/170, 711/171, 711/172, 711/173
• US Class Current: 711/103
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 12/04 Addressing variable-length words or parts of words
• CPC Class Codes: G06F 2212/7209 Validity control, e.g. using flags, time stamps or sequence numbers

Abstract

A non-volatile memory system, such as a flash EEPROM system, is disclosed to be divided into a plurality of blocks and each of the blocks into one or more pages, with sectors of data being stored therein that are of a different size than either the pages or blocks. One specific technique packs more sectors into a block than pages provided for that block. Error correction codes and other attribute data for a number of user data sectors are preferably stored together in different pages and blocks than the user data.

Claims

1. In a non-volatile memory having an array of memory cells divided into a plurality of units of a minimum number of memory cells that are simultaneously erasable, the memory cells of the erasable units being individually divided into a plurality of units of a minimum number of memory cells adapted to be programmed together with a unit of user data plus overhead data, a method of operating the memory comprising programming a number of units of user data into individual erasable units that exceed the number of programming units in an erasable unit by using at least some of the programming unit memory cells provided for storing overhead data to store portions of individual units of user data that are programmed into more than one programming unit.

2. The method of claim 1, additionally comprising storing overhead data associated with individual units of user data into one of the erasable units different from the erasable unit in which the units of user data are programmed.

3. The method of claim 2, wherein overhead data associated with units of user data programmed into a plurality of erasable units are stored in another one of the erasable units.

4. The method of claim 2, wherein no overhead data are stored in the same erasable units as user data.

5. The method of any one of claims 1-4, additionally comprising operating the memory cells with a plurality of effective threshold levels in excess of two that correspond to a plurality of alterable states of the individual cells in excess of two, whereby charge storage elements of the cells individually store more than one bit of data.