Memory Controller Refresh Control Using Population Error Scans
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Solution Overview
Problem
Existing memory management systems in NAND flash memory systems inefficiencies lead to unnecessary refresh operations, consuming resources and reducing the lifespan of memory cells due to a one-size-fits-all error management approach that does not account for varying cell tolerances to temperature and wear.
Innovation Solution
A memory sub-system controller dynamically controls refresh and folding operations based on error counts across multiple portions of a block stripe, selectively performing these operations only when specific thresholds are transgressed, thereby optimizing resource use and extending cell lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a one-size-fits-all error management approach is used for memory components, then simplicity of management is achieved, but unnecessary refresh operations occur consuming resources and reducing memory cell lifespan
Solution Approach 1:
The patent applies local quality by transitioning from uniform error management across all memory components to individualized management. Each memory component receives tailored refresh operations based on its specific error characteristics, temperature tolerance, and wear state. The controller monitors and manages each component separately, applying maintenance only where and when needed rather than universally.
Solution Approach 2:
The patent implements dynamics by making the error management approach adaptive rather than static. The controller dynamically adjusts refresh operations based on real-time monitoring of error counts, temperature conditions, and wear states for each memory component. This dynamic adjustment allows the system to respond to changing conditions and prevent unnecessary operations.
2Reliability
If refresh operations are performed frequently to ensure data integrity, then reliability is improved, but resource consumption increases and memory cell lifespan is reduced
Solution Approach 1:
The patent applies feedback by implementing continuous monitoring of error counts for each memory component. The controller uses this feedback information to make informed decisions about when refresh operations are actually needed. By basing refresh decisions on real error data rather than predetermined schedules, the system maintains data integrity while avoiding unnecessary operations that consume resources.
Solution Approach 2:
The patent implements parameter changes by adjusting refresh operation parameters based on monitored error characteristics. Rather than using fixed refresh intervals, the system modifies refresh timing and intensity according to actual error rates, temperature conditions, and wear states. This parameter adaptation ensures reliability is maintained at the minimum necessary level rather than through excessive operations.
3Device complexity
If uniform refresh operations are applied to all memory components, then operational simplicity is maintained, but efficiency is reduced due to unnecessary refreshes
Solution Approach 1:
The patent applies segmentation by dividing the memory system into individual manageable components, each with its own error characteristics and management requirements. Rather than treating all memory components as a single unit requiring uniform management, the system segments monitoring and control at the component level. This segmentation enables targeted refresh operations that improve efficiency while the automated nature of individual component management keeps complexity manageable.
Data Source
AI summary
The present disclosure configures a system component, such as a memory sub-system controller, to provide adaptive media management based on bit error rates. The controller receives a request to read data from an individual memory component of a set of memory components and, in response to receiving the request to read the data, reads the data from the individual memory component. The controller computes a number of errors associated with reading the data from the individual memory component. The controller determines whether the number of errors satisfies a refresh condition and selectively refreshes the data stored in the individual memory component based on whether the number of errors satisfies the refresh condition.