Configuration parameter management for non-volatile data storage

Patent metadata

Field	Value
Publication number	US-2018090213-A1
Application number	US-201715828407-A
Country	US
Kind code	A1
Filing date	Nov 30, 2017
Priority date	Nov 19, 2014
Publication date	Mar 29, 2018
Grant date	—

Abstract

Apparatuses, systems, and methods are disclosed for managing configuration parameters for non-volatile data storage. A control module is configured to limit erase dwell times for blocks of a non-volatile memory medium to satisfy a threshold. A block classification module is configured to group blocks of a non-volatile memory medium based on retention times for the blocks. A block access module is configured to access at least one group of blocks using a read voltage threshold selected based on a grouping.

First claim

What is claimed is:

1 . A method comprising:
programming and erasing blocks of a non-volatile storage medium such that variation of an erase dwell time for the blocks remains within a predetermined range; grouping the blocks of the non-volatile storage medium based on retention times for the blocks; and accessing at least one of the groups of blocks using a configuration parameter selected based on the grouping.

2 . The method of claim 1 , further comprising storing a single set of one or more configuration parameters per group such that the single set for a group is used for blocks of the group.

3 . The method of claim 1 , wherein the blocks are grouped using larger ranges of retention times for groups associated with larger retention times.

4 . The method of claim 1 , further comprising controlling variation for a program/erase cycle count for the blocks of the non-volatile storage medium.

5 . The method of claim 1 , wherein the erase dwell time comprises an elapsed time between erasing one of the blocks and writing data to the erased block.

6 . The method of claim 1 , wherein grouping the blocks is further based on one or more of one or more of die-to-die variation and a partially programmed state for one or more of the blocks of the non-volatile storage medium.

7 . The method of claim 1 , further comprising storing, for each group, a set of one or more threshold values for boundaries between discrete values stored by storage cells of the non-volatile storage medium.

8 . The method of claim 1 , further comprising updating the configuration parameter for a block in response to regrouping the block based on a change in a retention time for the block.

9 . The method of claim 1 , further comprising determining a new configuration parameter for at least one of the groups of blocks in response to a change in a program/erase cycle count.

10 . The method of claim 9 , wherein determining the new configuration parameter for one of the groups of blocks comprises:
sampling one or more blocks from the group; accessing the sampled blocks multiple times with different values for the new configuration parameter; and selecting a value from the different values for the new configuration parameter based on an error characteristic for the sampled blocks.

11 . The method of claim 9 , wherein determining the new configuration parameter for one of the groups of blocks comprises selecting the new configuration parameter from a set of predetermined configuration parameters based on the grouping.

12 . The method of claim 9 , wherein the change in the program/erase cycle count comprises the program/erase cycle count satisfying a threshold.

13 . An apparatus comprising:
a control module configured to limit erase dwell times for blocks of a non-volatile memory medium to satisfy a threshold; a block classification module configured to group blocks of a non-volatile memory medium based on retention times for the blocks; and a block access module configured to access the at least one group of blocks using a read voltage threshold selected based on the grouping.

14 . The apparatus of claim 13 , further comprising a configuration parameter module configured to store a single set of one or more read voltage thresholds per group such that the single set for a group is used for blocks of the group.

15 . The apparatus of claim 13 , wherein an erase dwell time comprises an elapsed time between erasing a block and writing data to the block.

16 . The apparatus of claim 13 , wherein the block access module is configured to use a first read voltage threshold to access a fully programmed block and to use a second read voltage threshold, different from the first read voltage threshold, to access a partially programmed block.

17 . A system comprising:
a non-volatile storage device comprising a non-volatile storage medium; and a controller for the non-volatile storage device, that
manages variation of erase dwell times for blocks of the non-volatile storage medium,
categorizes the blocks into groups based on retention times, and
configures different groups to use different read voltage thresholds based on the retention times.

18 . The system of claim 17 , wherein the controller updates a read voltage threshold for a block in response to regrouping the block based on a change in a retention time for the block.

19 . The system of claim 17 , wherein the controller updates a read voltage threshold for at least one of the groups in response to a change in a program/erase count.

20 . The system of claim 17 , wherein the controller comprises one or more of a hardware controller for the non-volatile storage device and a device driver for the non-volatile storage device, the device driver comprising computer executable code stored on a non-volatile computer readable storage medium.

Assignees

• Sandisk Technologies Llc

Inventors

• Peterson James
• Janik Gary
• Hyun Jea

Classifications

• G11C11/5642

  Sensing or reading circuits; Data output circuits · CPC title

• G11C2211/5641

  Multilevel memory having cells with different number of storage levels · CPC title

• G11C16/349

  Arrangements for evaluating degradation, retention or wearout, e.g. by counting erase cycles · CPC title

• G11C16/3418

  Disturbance prevention or evaluation; Refreshing of disturbed memory data · CPC title

• G11C8/12

  Group selection circuits, e.g. for memory block selection, chip selection, array selection · CPC title