EP0618535A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
EEprom card with defective cell substitution
Assignee: SanDisk Corp
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Filing: 1990-03-30
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Granted: —
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Expires: 2010-03-30
Abstract
Abstract A system of Flash EEprom memory chips with controlling circuits serves as non-volatile memory such as that provided by magnetic disk drives. Improvements include the ability to remap and replace defective cells with substitute cells. The remapping is performed automatically as soon as a defective cell is detected. When the number of detects in a Flash sector becomes large, the whole sector is remapped. In one embodiment, the Flash EEprom memory is implemented on a memory card adapted to plug into a computer system. In another embodiment, the system of Flash EEPROM memory chips with controlling circuits is implemented on a memory card adapted to plug into a computer system.
Inventors
- 👤 Eliyahou Harari
- 👤 Robert D. Norman
- 👤 Sanjay Mehrotra
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 08:11
CPC Classifications
G; G11; G11C; G11C29/00; G11C29/04; G11C29/08; G11C29/12; G11C29/18; G11C29/26; G06; G06F; G06F12/00; G06F12/02; G06F12/0223; G06F12/023; G06F12/0238; G06F12/0246; G06F12/08; G06F12/0802; G06F12/0804; G06F12/0866; G06F12/0875; G06F12/12; G06F12/121; G06F12/123; G06F3/00; G06F3/06; G06F3/0601; G06F3/0602; G06F3/0614; G06F3/0616; G06F3/0628; G06F3/0638; G06F3/064; G06F3/0646; G06F3/0652; G06F3/0668; G06F3/0671; G06F3/0673; G06F3/0679; G06F3/068; G06F3/0683; G06F3/0688; G11C11/00; G11C11/56; G11C11/5621; G11C11/5628; G11C11/5635; G11C16/00; G11C16/02; G11C16/06; G11C16/10; G11C16/14; G11C16/16; G11C16/34; G11C16/3436; G11C16/344; G11C16/3445; G11C16/3454; G11C16/3459; G11C29/52; G11C29/70; G11C29/76; G11C29/765; G11C29/78; G11C29/80; G11C29/816; G11C29/82; G11C7/00; G11C7/10; G11C7/1015; G11C7/1039; G11C8/00; G11C8/12; G06F11/00; G06F11/07; G06F11/08; G06F11/10; G06F11/1008; G06F11/1068; G06F2212/00; G06F2212/20; G06F2212/202; G06F2212/2022; G06F2212/31; G06F2212/312; G06F2212/72; G06F2212/7201; G06F2212/7203; G06F2212/7205; G06F2212/7207; G06F2212/7208; G06F3/0662; G06F3/0664; G11C2211/00; G11C2211/56; G11C2211/562; G11C2211/5621; G11C2211/563; G11C2211/5634; G11C2211/564; G11C2211/5643; G11C2216/00; G11C2216/12; G11C2216/18; G11C29/30; G11C29/34
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
173 words
A memory card adapted to plug into a computer system in a manner to communicate with a system bus and a standard power supply, comprising the following mounted thereon: a plurality of EEprom integrated circuit chips, each of said chips including: a large number of individually addressable storage cells organized into a plurality of sectors, each sector containing a plurality of said storage cells, a plurality of spare storage cells within any of said sectors, means responsive to signals on said system bus for erasing all cells in one or more designated sectors without erasing cells in others of said sectors, means responsive to signals on said system bus for reading the state of addressed storage cells, means responsive to signals on said system bus for programming addressed storage cells to a predetermined state, and means responsive to an unsuccessful attempt to either program or erase a storage cell within one of said sectors for substituting one of said spare storage cells therefore while maintaining operation of the remaining cells of said sector.
Claim 2
Dependent Claim
89 words
The memory card according to claim 1 which additionally comprises a cache memory mounted on said card, and wherein said programming means includes means for initially programming said cache memory rather than said EEprom memory, said reading means includes means for initially determining whether the cache memory contains data to be read, and said programming means additionally includes means responsive to said cache memory becoming full for writing its oldest unused block of data into said EEprom memory, thereby to make room for new data in said cache memory.
Claim 3
Dependent Claim
50 words
The memory card as in claim 1, wherein each of said chips further includes a plurality of spare sectors, and wherein said substituting means also substitutes one of said spare sectors for one of said sectors when a predetermined number of cells in said one of said sector become defective.
Claim 4
Dependent Claim
17 words
The memory card as in claim 3, including means for performing error correction using error correction codes.
Claim 5
Dependent Claim
47 words
The memory card as in claim 1, including a controller and an interface connected to the system bus, said controller being adapted to be responsive to commands intended for a standard magnetic disk drive storage system connectable to the computer system, thereby emulating said disk drive system.
Claim 6
Dependent Claim
34 words
The memory card as in claim 1, in which various operating voltages are required for various operations of the EEprom chips, including means for generating the various operating voltages from the standard power supply.
Claim 7
Dependent Claim
56 words
A storage system incorporating therein the memory card of claim 1 , comprising: a controller for controlling the operation of the EEprom chips; means for generating voltages for the operation of the EEprom chips; means for error correction in the operation of the storage system; and means for interfacing the storage system to a computer system.
References Cited (Backward Citations)
No citation records indexed.
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