Flash memory wear leveling system and method
First Claim
1. A method of wear leveling a flash memory cell array, comprising the steps of:
- detecting the time required to complete an erasing operation on a sector of the memory cell array; and
determining whether to continue using the sector based on the detected erasing time.
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Accused Products
Abstract
A wear leveling system and method of a flash memory cell uses the amount of time required to perform an erasing operation on a sector of the flash memory to determine whether the memory cells in the sector have degraded to an unacceptable level. The actual time required to erase a sector of a flash memory array is compared to a reference erasing time required to erase a unit sector under the state of the worst allowable degradation. If the actual erasing time of a sector exceeds the reference erasing time, logical addresses corresponding to the sector are re-mapped to the physical addresses of a different sector. On the other hand, when the actual erasing time is shorter than or equal to the reference erasing time, a controller continues to use the unit sector.
157 Citations
19 Claims
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1. A method of wear leveling a flash memory cell array, comprising the steps of:
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detecting the time required to complete an erasing operation on a sector of the memory cell array; and determining whether to continue using the sector based on the detected erasing time. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A wear leveling system of a flash memory cell array, comprising:
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a detector configured to detect an amount of time required for memory cells of a sector of said flash memory cell array to be erased; and a comparator configured to compare a reference erasing time to said detected erasing time. - View Dependent Claims (9, 10, 11, 12)
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13. A wear leveling method of a flash memory cell array having at least one sector, comprising the steps of:
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detecting a data erasing time of a sector in said flash memory cell array; and comparing the detected data erasing time to a predetermined reference erasing time to check the wear status of the sector. - View Dependent Claims (14, 15, 16)
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17. A method of wear leveling a flash memory cell array, comprising the steps of:
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detecting a time required to erase data from memory cells of a sector of the memory cell array; and re-mapping the memory cell array if the detected erasing time exceeds a predetermined reference erasing time so that the sector is no longer used to store data. - View Dependent Claims (18, 19)
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Specification