Adaptive read trim for second read data retention
A data storage system performs operations including determining an endurance level of a block of memory cells; adjusting a read performance profile for the block of memory cells based on the determined endurance level; receiving a data read command specifying data to be read from a particular memory cell of the block of memory cells; and in response to the data read command, performing a read operation on the particular memory cell using the adjusted read performance profile.
1. A data storage system, comprising a memory comprising a plurality of memory cells; and a controller in communication with the memory, the controller configured to:
determine an endurance level of a block of memory cells of the plurality of memory cells;
increase at least one of a read voltage ramp-up time, a read voltage stabilization time, a read voltage sense time, and/or a read voltage discharge time for the block of memory cells based on the determined endurance level;
receive a data read command specifying data to be read from a particular memory cell of the block of memory cells; and
in response to the data read command, perform a read operation on the particular memory cell using the increased read voltage ramp-up time, read voltage stabilization time, read voltage sense time, and/or read voltage discharge time.
2. The data storage system of claim 1 , wherein the controller being configured to determine the endurance level of the block of memory cells includes the controller being configured to:
increment an erase count associated with the block of memory cells each time the block of memory cells is erased; and
determine the endurance level based on the erase count.
3. The data storage system of claim 1 , wherein the controller being configured to determine the endurance level of the block of memory cells includes the controller being configured to:
compare an erase count associated with the block of memory cells with one or more erase count thresholds associated with beginning-of-life (BOL), middle-of-life (MOL), end-of-life (EOL), and beyond end-of-life (BEOL) classifications of the block of memory cells; and
determine the endurance level based on the comparison.
4. The data storage system of claim 1 , wherein the controller being configured to determine the endurance level of the block of memory cells includes the controller being configured to:
determine an erase count of one or more of the memory cells of the block of memory cells; and
determine the endurance level based on the erase count.
5. The data storage system of claim 1 , wherein the controller being configured to increase at least one of the read voltage ramp-up time, read voltage stabilization time, read voltage sense time, and/or read voltage discharge time for the block of memory cells based on the determined endurance level includes the controller being configured to:
determine whether the determined endurance level is associated with an EOL classification; and
in accordance with a determination that the determined endurance level is associated with the EOL classification, increase at least one of the read voltage ramp-up time, read voltage stabilization time, read voltage sense time, and/or read voltage discharge time for the block of memory cells.
6. The data storage system of claim 1 , wherein the controller being configured to increase at least one of the read voltage ramp-up time, read voltage stabilization time, read voltage sense time, and/or read voltage discharge time for the block of memory cells based on the determined endurance level includes the controller being configured to:
set at least one of the read voltage ramp-up time, read voltage stabilization time, read voltage sense time, and/or read voltage discharge time to a first value in accordance with a determination that the determined endurance level is associated with a MOL classification; and
increase at least one of the read voltage ramp-up time, read voltage stabilization time, read voltage sense time, and/or read voltage discharge time to a second value in accordance with a determination that the determined endurance level is associated with an EOL classification.
7. A data storage system, comprising a memory comprising a plurality of memory cells; and a controller in communication with the memory, the controller configured to:
in response to receiving a refresh read command, for each metablock of the plurality of memory cells:
determine an endurance level of the metablock;
compare the determined endurance level to a predetermined life cycle threshold;
in accordance with a determination that the determined endurance level exceeds the predetermined life cycle threshold:
determine whether the metablock includes any single level cell (SLC) memory cells; and
in accordance with a determination that the metablock does not include any SLC memory cells, perform a refresh read operation on the metablock; and
in accordance with a determination that the metablock includes an SLC memory cell, forgo performing the refresh read operation on the metablock, and perform a second refresh read operation on one or more blocks within the metablock which do not include any SLC memory cells.
8. The data storage system of claim 7 , wherein the controller is further configured to:
in accordance with a determination that the determined endurance level does not exceed the predetermined life cycle threshold, perform the refresh read operation on the metablock.
9. The data storage system of claim 7 , wherein the controller being configured to determine whether the metablock includes any SLC memory cells includes the controller being configured to search for the metablock in a listing of metablocks that include SLC memory cells.
10. The data storage system of claim 7 , wherein the controller being configured to perform the refresh read operation on the metablock includes the controller being configured to:
apply a pre-conditioning voltage to a plurality of word lines in the metablock in order to move the memory cells into, or keep the memory cells in, a second read condition.
11. A data storage system, comprising:
means for determining an endurance level of a block of memory cells;
means for increasing at least one of a read voltage ramp-up time, a read voltage stabilization time, a read voltage sense time, and/or a read voltage discharge time for the block of memory cells based on the determined endurance level;
means for receiving a data read command specifying data to be read from a particular memory cell of the block of memory cells; and
means for, in response to the data read command, performing a read operation on the particular memory cell using the increased read voltage ramp-up time, read voltage stabilization time, read voltage sense time, and/or read voltage discharge time.
12. A method for a data storage system, comprising a memory comprising a plurality of memory cells; and a controller in communication with the memory, the method comprising:
at the controller:
determining an endurance level of a block of memory cells of the plurality of memory cells;
increase at least one of a read voltage ramp-up time, a read voltage stabilization time, a read voltage sense time, and/or a read voltage discharge time for the block of memory cells based on the determined endurance level;
receiving a data read command specifying data to be read from a particular memory cell of the block of memory cells; and
in response to the data read command, performing a read operation on the particular memory cell using the increased read voltage ramp-up time, read voltage stabilization time, read voltage sense time, and/or read voltage discharge time.
13. The method of claim 12 , wherein determining the endurance level of the block of memory cells includes:
incrementing an erase count associated with the block of memory cells each time the block is erased; and
determining the endurance level based on the erase count.
14. The method of claim 12 , wherein determining the endurance level of the block of memory cells includes:
comparing an erase count associated with the block of memory cells with one or more erase count thresholds associated with beginning-of-life (BOL), middle-of-life (MOL), end-of-life (EOL), and beyond end-of-life (BEOL) classifications of the block of memory cells; and
determining the endurance level based on the comparison.
15. The method of claim 12 , wherein determining the endurance level of the block of memory cells includes:
determining an erase count of one or more of the memory cells of the block of memory cells; and
determining the endurance level based on the erase count.
16. The method of claim 12 , wherein increasing at least one of the read voltage ramp-up time, read voltage stabilization time, read voltage sense time, and/or read voltage discharge time for the block of memory cells based on the determined endurance level includes:
determining whether the determined endurance level is associated with an EOL classification; and
in accordance with a determination that the determined endurance level is associated with the EOL classification, increasing at least one of the read voltage ramp-up time, read voltage stabilization time, read voltage sense time, and/or read voltage discharge time for the block of memory cells.
17. The method of claim 12 , wherein increasing at least one of the read voltage ramp-up time, read voltage stabilization time, read voltage sense time, and/or read voltage discharge time for the block of memory cells based on the determined endurance level includes:
setting at least one of the read voltage ramp-up time, read voltage stabilization time, read voltage sense time, and/or read voltage discharge time to a first value in accordance with a determination that the determined endurance level is associated with a MOL classification; and
increasing at least one of the read voltage ramp-up time, read voltage stabilization time, read voltage sense time, and/or read voltage discharge time to a second value in accordance with a determination that the determined endurance level is associated with an EOL classification.