EP0617363A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Defective cell substitution in EEprom array
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 defects in a Flash sector becomes large, the whole sector is remapped.
Inventors
- 👤 Eliyahou Harari
- 👤 Robert D. Norman
- 👤 Sanjay Mehrotra
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 12:13
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: 20
Claim 1
Independent Claim
35 words
A system for correcting errors from defective cells within an array of Flash EEprom cells, comprising: substitute cells; means for substituting one or more of the defective cells with a corresponding number of substitute cells.
Claim 2
Dependent Claim
36 words
A system for correcting errors from defective cells within an array of Flash EEprom cells as in claim 1 wherein the substituting means also applies automatically to new defective cells as soon as they are detected.
Claim 3
Dependent Claim
55 words
A system for correcting errors from defective cells within an array of Flash EEprom cells as in claim 1 , said array being partitioned into a plurality of Flash erasable sectors such that all cells within each sector are erasable at once, wherein the substitute cells are in the same sector as the defective cells.
Claim 4
Dependent Claim
43 words
A system for correcting errors from defective cells within an array of Flash EEprom cells as in claim 2, further comprising a defect map for storing defect pointers which link the addresses of the defective cells to that of the corresponding substitute cells.
Claim 5
Dependent Claim
38 words
A system for correcting bad data in defective cells within an array of Flash EEprom cells as in claim 4, wherein the defect map for said defective cells are located in the same sector as said defective cells.
Claim 6
Dependent Claim
84 words
A system for correcting errors from defective cells within an array of Flash EEprom cells as in claim 1 , said array being partitioned into a plurality of Flash erasable sectors such that all cells within each sector are erasable at once, wherein the substitute cells are in the same sector as the defective cells when the number of defective cells in the sector does not exceed a predetermined number, and the substitute cells are in a different sector when the number is exceeded.
Claim 7
Dependent Claim
37 words
A system for correcting errors from defective cells within an array of Flash EEprom cells as in claim 6 , wherein said sector is replaced in its entirety by a substitute sector when said number is exceeded.
Claim 8
Dependent Claim
35 words
A system for correcting errors from defective cells within an array of Flash EEprom cells as in claim 6 wherein the substituting means also applies automatically new defective cells as soon as they are detected.
Claim 9
Dependent Claim
26 words
A system for correcting errors from defective cells within an array of Flash EEprom cells as in claim 8, including the use of error correction codes.
Claim 10
Independent Claim
57 words
A system for correcting bad data in defective cells within an array of Flash EEprom cells, comprising: substitute cells for storing good data intended for the defective cells; means for substituting the bad data in one or more of the defective cells with the good data in the corresponding substitute cells when the defective cells are accessed.
Claim 11
Independent Claim
50 words
A system for correcting bad data in defective cells within an array of Flash EEprom cells as in clain 10, further comprising means for automatically saving the good data intended to be written to the defective cells to the corresponding substitute cells, thereby perserving the integrity of the good data.
Claim 12
Dependent Claim
37 words
A system for correcting bad data in defective cells within an array of Flash EEprom cells as in claim 11 wherein the substituting means also applies automatically to new defective cells as soon as they are detected.
Claim 13
Dependent Claim
62 words
A system for correcting bad data in defective cells within an array of Flash EEprom cells as in claim 11, said array being partitioned into a plurality of Flash erasable sectors such that all cells within each sector are erasable at once, and data is stored therein, wherein the substituting means applies after the data including the bad data has been accessed.
Claim 14
Dependent Claim
56 words
A system for correcting bad data in defective cells within an array of Flash EEprom cells as in claim 11 , said array being partitioned into a plurality of Flash erasable sectors such that all cells within each sector are erasable at once, wherein the substitute cells are in the same sector as the defective cells.
Claim 15
Dependent Claim
44 words
A system for correcting bad data in defective cells within an array of Flash EEprom cells as in claim 11, further comprising a defect map for storing defect pointers which link the addresses of the defective cells to that of the corresponding substitute cells.
Claim 16
Dependent Claim
38 words
A system for correcting bad data in defective cells within an array of Flash EEprom cells as in claim 15, wherein the defect map for said defective cells are located in the same sector as said defective cells.
Claim 17
Dependent Claim
84 words
A system for correcting bad data in defective cells within an array of Flash EEprom calls as in claim 10, said array being partitioned into a plurality of Flash erasable sectors such that all cells within each sector are erasable at once, wherein the substitute cells are in the same sector as the defective cells when the number of defective cells in the sector does not exceed a predetermined number, and the substitute cells are in a different sector when the number is exceeded.
Claim 18
Dependent Claim
37 words
A system for correcting bad data in defective cells within an array of Flash EEprom cells as in claim 17, wherein said sector is replaced in its entirety by a substitute sector when said number is exceeded.
Claim 19
Dependent Claim
32 words
A system for correcting bad data in defective cells within an array of Flash EEprom cells as in claim 17, wherein the substituting means also applies automatically to newly occurring defective cells
Claim 20
Dependent Claim
26 words
A system for correcting bad data in defective cells within an array of Flash EEprom cells as in claim 19, including use of error correction codes.
References Cited (Backward Citations)
No citation records indexed.
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