Flash Memory Block Grouping by Quality Index
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Solution Overview
Problem
The existing flash memory storage devices face issues due to varying quality of internal memory cells, leading to increased read error rates, reduced lifetime, and inefficient usage, as conventional methods either avoid low-quality cells or waste higher-quality cells by maintaining uniform quality.
Innovation Solution
A memory control device and method that groups memory blocks based on quality indices, initially prioritizing higher-quality blocks and gradually enabling lower-quality blocks as the higher-quality ones degrade, optimizing access performance and usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If memory blocks are grouped and accessed based on quality index, then access efficiency and memory usage are balanced, but device complexity increases due to quality assessment and group management
Solution Approach 1:
The patent applies preliminary action by assessing and recording the quality index of memory blocks in advance during manufacturing or initial operation. The control circuit pre-groups memory blocks into first and second groups based on these pre-assessed quality indices, so that when data storage or retrieval operations occur, the system can directly access the appropriate group without performing complex real-time quality assessments, thereby maintaining high access efficiency while managing complexity through upfront preparation
Solution Approach 2:
The patent segments the memory blocks into distinct groups (first memory group and second memory group) based on quality indices. This segmentation allows the control circuit to manage different quality categories separately, directing operations to appropriate groups based on data requirements. The segmentation simplifies the access process by creating clear boundaries between quality levels while still enabling efficient utilization of memory resources across different quality tiers
2Reliability
If conventional methods directly indicate inability to use low quality memory cells, then quality consistency is ensured, but memory cell wastage increases
Solution Approach 1:
The patent applies local quality by recognizing that different memory blocks have different quality characteristics and treating them accordingly rather than applying a uniform quality standard. The control circuit assigns different quality indices to different memory blocks and creates separate access strategies for first group blocks (higher quality) and second group blocks (lower quality). This allows the system to utilize memory blocks with varying quality levels appropriately, ensuring data integrity while maximizing memory cell usage and reducing wastage
Solution Approach 2:
The patent changes the quality assessment parameter from a binary usable/unusable classification to a multi-level quality index system. By introducing quality indices and grouping memory blocks into different categories based on these indices, the system can dynamically adjust access parameters and strategies for different quality levels. This parameter change enables the system to utilize previously discarded low-quality blocks while maintaining reliability through appropriate access methods for each quality group
3Ease of operation
If uniform quality management is applied to all memory cells, then management simplicity is maintained, but access performance deteriorates due to quality differences
Solution Approach 1:
The patent introduces dynamics by making the memory access strategy adaptive rather than static. The control circuit dynamically selects which memory group to access based on the quality index requirements of the data being stored or retrieved. The system can transition between accessing first group blocks and second group blocks depending on operational needs, quality index thresholds, and wear levels. This dynamic approach maintains relatively simple management procedures while significantly improving access performance by matching memory block quality to data requirements
Data Source
AI summary
An apparatus and a method for accessing a plurality of memory blocks is disclosed. The An apparatus comprises: a memory circuit configured to store a recording table, wherein the recording table corresponds to quality index of the plurality of memory blocks; and a control circuit configured to group the plurality of memory blocks to a first memory group and a second memory group according to the quality index; to enable to access the memory blocks in the first memory group, and to disable to access the memory blocks in the second memory group.