Memory Block Validity Detection After Power Loss
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Solution Overview
Problem
Memory devices face performance issues and resource consumption problems due to automatic block abandonment after power loss, leading to write amplification and reduced efficiency, especially when dealing with mixed SLC blocks where charge loss and gain variations are not accurately detected.
Innovation Solution
A memory sub-system that determines the validity of open blocks for programming after power restoration by analyzing charge loss and gain metrics, using wordline-level detection techniques to assess the block's suitability for continued writing, and adjusting index values to compensate for charge loss, thereby extending the life of open blocks and improving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If automatic block abandonment is implemented after power loss, then data integrity is protected, but write amplification increases and productivity decreases
Solution Approach 1:
The system performs preliminary detection of charge loss and gain metrics for open blocks before attempting to resume programming after power loss. By analyzing these metrics in advance, the system can determine block validity before writing operations, preventing unnecessary block abandonment and reducing write amplification while maintaining data integrity.
Solution Approach 2:
The system implements feedback mechanisms by continuously monitoring charge loss and gain metrics during and after programming operations. This feedback allows the system to adapt its block abandonment decisions based on actual charge state changes, reducing unnecessary block rejections and improving writing efficiency while ensuring data safety.
2Device complexity
If charge loss and gain variations are not accurately detected, then device complexity is reduced, but manufacturing precision and reliability deteriorate
Solution Approach 1:
The system segments the charge detection process into distinct components: charge loss detection for programmed pages and charge gain detection for erased pages. This segmentation allows accurate detection of different charge states using specialized detection techniques, improving manufacturing precision without requiring a single complex unified detection mechanism.
Solution Approach 2:
The system applies different detection approaches and threshold criteria for different types of pages (programmed vs. erased) within the same block. This local quality approach allows optimized detection for each page type, improving overall charge state detection accuracy while managing device complexity through targeted rather than universal detection methods.
3Productivity
If open blocks are extended after power loss, then productivity improves, but reliability may deteriorate due to uncertain charge states
Solution Approach 1:
The system replaces mechanical block abandonment decisions with a more nuanced charge-state-based validation mechanism. By substituting the binary abandon/continue approach with a charge metric analysis system, the platform can make informed decisions about block validity, improving productivity through continued programming while maintaining reliability through data-driven block selection.
Data Source
AI summary
A system includes a memory device and a processing device, operatively coupled with the memory device, to perform operations including identifying an open block of the memory device, determining, based on at least one charge loss metric associated with a set of programmed pages of the open block or at least one charge gain metric associated with a set of erased pages of the open block, whether the open block is valid for programming, and responsive to determining that the open block is not valid for programming, abandoning the open block.