Adaptive error correction for non-volatile memories
First Claim
1. A memory system, comprising:
- an array of memory cells;
sense amplifier circuitry configured to provide data output signals associated with sensed voltage levels for a plurality of memory cells within the array of memory cells, the sense amplifier circuitry having read detection windows for the sensed voltage levels; and
memory control circuitry configured to receive the data output signals and to identify and correct bit errors within the data output signals by applying at least one error correction control (ECC) routine, the memory control circuitry being further configured to vary the read detection windows by adjusting at least one operating parameter when an identified bit error is not correctable by the at least one ECC routine and to cause the sense amplifier circuitry to re-sense voltage levels for the plurality of memory cells using the adjusted at least one operating parameter; and
data storage circuitry;
wherein the memory control circuitry is further configured to vary the read detection windows until detected but uncorrectable bit errors are corrected and to output corrected data, to store the corrected data and an address for the not correctable error in the data storage circuitry, and to access the stored corrected data if a subsequent read operation addresses data from the address.
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Accused Products
Abstract
Adaptive error correction for non-volatile memories is disclosed that dynamically adjusts sense amplifier read detection windows. Memory control circuitry uses error correction code (ECC) routines to detect bit errors that are non-correctable using these ECC routines. The memory control circuitry then dynamically adjusts sense amplifier read detection windows to allow for correct data to be determined. Corrected data can then be output to external circuitry. The corrected data can also be stored for later access when subsequent read operations attempt to access address locations that previously suffered bit failures. The adaptive error correction can also be used with respect to memories that are not non-volatile memories.
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Citations
14 Claims
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1. A memory system, comprising:
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an array of memory cells; sense amplifier circuitry configured to provide data output signals associated with sensed voltage levels for a plurality of memory cells within the array of memory cells, the sense amplifier circuitry having read detection windows for the sensed voltage levels; and memory control circuitry configured to receive the data output signals and to identify and correct bit errors within the data output signals by applying at least one error correction control (ECC) routine, the memory control circuitry being further configured to vary the read detection windows by adjusting at least one operating parameter when an identified bit error is not correctable by the at least one ECC routine and to cause the sense amplifier circuitry to re-sense voltage levels for the plurality of memory cells using the adjusted at least one operating parameter; and data storage circuitry; wherein the memory control circuitry is further configured to vary the read detection windows until detected but uncorrectable bit errors are corrected and to output corrected data, to store the corrected data and an address for the not correctable error in the data storage circuitry, and to access the stored corrected data if a subsequent read operation addresses data from the address. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for reading data from a memory system, comprising:
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sensing voltage levels for a plurality of memory cells within an array of memory cells using sense amplifier circuitry, the sense amplifier circuitry having read detection windows for the sensed voltage levels; applying an error correction code (ECC) routine to identify and correct bit errors within data output signals associated with sensed voltage levels for the plurality of the memory cells; varying the read detection windows by adjusting at least one operating parameter when an identified bit error is not correctable using the ECC routine and determining an address for the not correctable error; and repeating the sensing, applying, and varying steps until the not correctable error is correctable using the ECC routine; outputting corrected data; storing the corrected data and the address in data storage circuitry; and accessing the stored corrected data if a subsequent read operation addresses data from the address. - View Dependent Claims (10, 11, 12, 13, 14)
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Specification