Dynamic refresh that changes the physical storage locations of data in flash memory
AssigneeMulti Level Memory Technology
InventorSau Ching Wong
Life of this patent
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Abstract
A multi-bit-per-cell non-volatile memory performs refresh operations that move data to different physical storage locations. The movement of data may extend the life of a non-volatile memory by avoiding repetitive erasing and writing of the same data value in the same memory cell. A memory mapping circuit in the memory adjusts for different storage configuration that the refresh operations create. In particular embodiments, shifts sectors-sized data blocks cyclically among sectors in an array, a bank, or an entire memory or alternatively shifts the data blocks between two configurations.
Claims18
A refresh operation for a non-volatile memory, comprising:
- (a) selecting a sector in the non-volatile memory;
- (b) erasing the selected sector;
- (c) reading a following sector, wherein the following sector follows the selected sector in an ordering of sectors of the non-volatile memory;
- (d) writing data from the following sector, to the selected sector;
- (e) repeating (b), (c), and (d) one or more times, where for each repetition, the selected sector for that repetition is the following sector last used.
A method for operating a non-volatile memory, comprising:
- performing a first refresh operation that reads data from a first location having first physical address in the non-volatile memory and writes the data to a second location having a second physical address in the memory;
- operating the memory using a first address mapping that maps a logical address corresponding to the data to the second physical address;
- performing a second refresh operation that reads the data from second locations in the non-volatile memory and writes the data to first locations in the memory;
- and
- operating the memory using a second address mapping that maps the logical address corresponding to the data to the second physical address.
A refresh operation for a non-volatile memory, comprising:
- reading first data from a first location in the non-volatile memory;
- reading second data from a second location in the non-volatile memory;
- erasing the first and second locations;
- writing the first data in the second location;
- and
- writing the second data in the first location.
Dependencies are inferred from the claim text.