Dynamic Memory Recharacterization for Wear Management
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Solution Overview
Problem
Flash memory devices face increased bit errors and faster wear as the number of bits stored per cell increases, leading to premature end-of-life conditions and device retirement.
Innovation Solution
A memory controller recharacterizes memory devices from a higher storage density to a lower one, such as from X2 to X1, to extend the operational life by reducing storage capacity and managing wear, thereby delaying end-of-life conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of bits stored per cell increases to enhance storage density, then data storage capacity is improved, but bit errors in stored data increase and memory cells wear faster
Solution Approach 1:
The patent implements dynamic recharacterization of memory device portions, allowing the storage density configuration to change over time based on wear conditions. The memory controller can transition portions from high-density configurations (X2, X3) to lower-density configurations (X1) as wear thresholds are approached, enabling the system to adapt its storage density dynamically to maintain reliability while maximizing overall device utilization
Solution Approach 2:
The patent changes the operational parameters of memory cells by recharacterizing them from one storage density mode to another. By modifying the threshold voltage distributions and programming/reading parameters, the system can convert worn high-density cells into functional lower-density cells, effectively changing the operational state of the memory portions to extend device life
2Quantity of substance
If the number of bits stored per cell increases to enhance storage density, then data storage capacity is improved, but memory cell wear increases leading to faster end-of-life conditions
Solution Approach 1:
The system dynamically adjusts the operational configuration of memory portions based on real-time wear monitoring. When wear thresholds are detected, the memory controller recharacterizes affected portions to lower storage density modes, allowing the device to continue operating beyond what would traditionally be considered end-of-life for the original high-density configuration
Solution Approach 2:
The patent effectively discards the high-density operational state for worn memory portions and recovers their utility by recharacterizing them to lower-density modes. This allows previously unusable worn cells to be recovered and continue providing storage capacity, extending the overall device lifespan
3Reliability
If the memory device is retired upon reaching end-of-life conditions to maintain reliability, then data retention reliability is preserved, but storage capacity is lost and device functionality ceases
Solution Approach 1:
The patent segments the memory device into multiple independent portions that can be managed separately. When certain portions reach wear thresholds, only those specific portions are recharacterized to lower storage density modes while the rest of the device continues operating at original performance levels. This granular segmentation allows selective remediation without affecting overall device functionality
Solution Approach 2:
The memory portions are designed to be multi-functional, capable of operating in multiple storage density modes (X1, X2, X3). This universality allows the same physical memory cells to serve different functional roles depending on their wear state, ensuring continuous device productivity across varying reliability conditions
Data Source
AI summary
A storage system includes a memory controller and a storage device with one or more memory devices, each with a plurality of memory portions. The memory controller determines an initial storage capacity for each of the one or more memory devices, where the one or more memory devices are configured in a first storage density. The memory controller detects a trigger condition as to at least one memory portion of a respective device of the one or more memory devices and, in response to detecting the trigger condition, recharacterizes the at least one memory portion of the respective memory device so as to be configured in a second storage density, where the at least one recharacterized memory portion of the respective memory device has a reduced storage capacity. After the recharacterizing, the memory controller determines a revised storage capacity for the respective memory device.