Background data refresh in storage devices

A memory device, comprising:

• a memory controller;
• and
• a non-volatile memory, wherein the non-volatile memory includes a plurality of X-level memory cells, and X is equal to an integer number greater than 1;
• memory storing one or more programs comprising instructions for:
• applying a readout voltage based on a reference voltage to read data stored in the plurality of X-level memory cells, each of the plurality of X-level memory cells configured to store a respective one of a plurality of successive integer values;
• based on the readout voltage, identifying a subset of memory cells of the plurality of memory cells storing a first value of the plurality of successive integer values, the first value being the largest integer value stored by the plurality of successive integer values;
• and
• programming the subset of memory cells to re-write the first value in the subset of memory cells.

A non-transitory computer-readable storage medium storing one or more programs configured for execution by one or more processors of a memory device, the one or more programs comprising instructions for:

• at the memory device, the memory device including a non-volatile memory having a plurality of X-level memory cells, X equal to an integer number greater than 1:
• applying a readout voltage based on a reference voltage to read data stored in the plurality of X-level memory cells, each of the plurality of X-level memory cells configured to store a respective one of a plurality of successive integer values;
• based on the readout voltage, identifying a subset of memory cells of the plurality of memory cells storing a first value of the plurality of successive integer values, the first value being the largest integer value stored by the plurality of successive integer values;
• and
• programming the subset of memory cells to re-write the first value in the subset of memory cells.