Systems and methods for refreshing non-volatile memory
AssigneeApple Inc.
InventorsMatthew Byom, Daniel J. Post, Vadim Khmelnitsky
Life of this patent
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Abstract
Systems and methods are disclosed for managing a non-volatile memory (“NVM”), such as a flash memory. To prevent data errors due to leakage effects, the NVM may be refreshed. For example, a reserved portion of the NVM may be selected, and a predetermined pattern can be stored into the reserved portion. The reserved portion can then be monitored for storage deterioration over time. After determining that storage deterioration of the reserved portion has occurred, the NVM can be refreshed. In some embodiments, a controller can attempt to distinguish data errors due to leakage effects from data errors due to disturb issues.
Claims32
A method for refreshing a non-volatile memory, the method comprising:
- selecting a portion of the non-volatile memory as a reserved portion;
- storing a predetermined pattern into the reserved portion;
- monitoring the reserved portion for storage deterioration;
- and
- in response to determining that storage deterioration of the reserved portion has occurred, refreshing the non-volatile memory.
A method for detecting deterioration of a reserved portion of a non-volatile memory, the method comprising:
- storing a predetermined pattern into the reserved portion of the non-volatile memory;
- determining if at least one event associated with a portion of the non-volatile memory has occurred;
- in response to determining that the at least one event associated with the portion of the non-volatile memory has occurred, determining if the reserved portion has deteriorated;
- and
- in response to determining that the reserved portion has deteriorated, refreshing the portion of the non-volatile memory.
A memory system comprising:
- a non-volatile memory comprising at least one die with multiple portions;
- and
- a controller for refreshing the non-volatile memory, wherein the controller is operative to:
- monitor a reserved portion of the non-volatile memory for storage deterioration;
- in response to determining that storage deterioration of the reserved portion has occurred, select a second portion of the non-volatile memory as a new reserved portion;
- and
- refresh the multiple portions of the non-volatile memory in a predetermined order.
Dependencies are inferred from the claim text.