Memory Read Count Weighting for Open-Block Disturb Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing memory devices face issues with read disturbance, where data integrity is compromised due to unintentional changes during read operations, particularly in open memory blocks with varying open area ratios and shared strings, leading to inconsistent read disturb effects.
Innovation Solution
The memory device employs a weight-based read count calculation method that adjusts read counts based on the open area ratio and string sharing within open memory blocks, applying different weights to reflect varying read disturbances and mitigating data corruption by data migration and wear leveling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If read operations are performed frequently to improve data access speed, then productivity is improved, but read disturbance increases causing data corruption
Solution Approach 1:
The patent applies different weight values to different memory blocks based on their specific characteristics (open area ratio, shared string status). Memory blocks with higher open area ratios or shared strings receive higher weights, reflecting their greater susceptibility to read disturbance. This localized differentiation allows the system to prioritize protection for vulnerable blocks while maintaining efficient access to robust blocks, resolving the contradiction between access speed and data stability.
Solution Approach 2:
The system dynamically changes the weight parameter assigned to each memory block based on varying conditions such as open area ratio and string sharing status. By adjusting these weights according to current memory block states, the system can adaptively manage read disturbance risks while maintaining high productivity. The weight parameter serves as a dynamic indicator that balances access efficiency with reliability.
2Device complexity
If weights are applied to all memory blocks uniformly to simplify management, then device complexity is reduced, but measurement precision of read disturbance is insufficient
Solution Approach 1:
Instead of uniform weight application, the patent implements local quality by assigning different weight values to different memory blocks based on their specific characteristics. Each block's weight reflects its individual susceptibility to read disturbance, enabling precise measurement and management. This approach increases measurement precision while keeping the management mechanism relatively simple through automated weight assignment based on observable block properties.
3Reliability
If read count is increased to reflect actual usage patterns, then reliability is improved, but device complexity increases due to weight calculation mechanisms
Solution Approach 1:
The system uses parameter changes (weight values) to enhance reliability without substantially increasing device complexity. The weight calculation is based on relatively simple characteristics like open area ratio and string sharing status, which can be determined through existing memory management structures. This parameter-based approach provides accurate read disturbance reflection while maintaining manageable system complexity through automated calculations.
Data Source
AI summary
A memory device includes an open memory block and control circuitry. The open memory block includes at least one first page having an erased state. The control circuitry is configured to perform a read operation for a page included in the open memory block, and apply a weight determined based on a ratio of the at least one first page in the open memory block to calculate a read count subject to the read operation.