Auxiliary Cell Threshold Voltage Detection for Memory Wear Monitoring
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Solution Overview
Problem
Non-volatile memory devices face challenges in accurately determining the deterioration level of memory cells, leading to reduced durability and lifetime due to repeated programming and erasing operations, which can result in data loss and impaired read/write operations.
Innovation Solution
The method involves detecting the threshold voltage of auxiliary cells connected in series with memory cells, generating an output signal based on this voltage, and using a memory controller to determine the deterioration level of memory cells, allowing for controlled operations to prevent wear and tear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If repeated programming and erasing operations are performed on memory cells, then data storage capacity is maintained, but durability and lifetime are reduced
Solution Approach 1:
The patent applies preliminary action by detecting the threshold voltage of auxiliary cells before the memory cells reach critical deterioration levels. This early detection enables proactive wear leveling management, allowing the system to redistribute data before actual failures occur, thus extending the overall lifetime of the memory device while maintaining reliability.
Solution Approach 2:
The patent implements feedback mechanisms by continuously monitoring the threshold voltage of auxiliary cells and using this information to dynamically adjust wear leveling strategies. The memory controller receives feedback about cell deterioration levels and modifies programming/erasing operations accordingly, optimizing both durability and lifetime by preventing excessive wear on already stressed cells.
2Measurement precision
If threshold voltage detection is performed on memory cells, then deterioration level can be determined, but measurement precision is reduced due to interference from programming and erasing operations
Solution Approach 1:
The patent applies segmentation by separating the detection function into dedicated auxiliary cells that are distinct from the main memory cells. This segmentation allows threshold voltage detection to be performed on auxiliary cells without interfering with the data stored in memory cells, achieving both precise deterioration measurement and data integrity. The auxiliary cells serve as separate sensors that reflect the wear state without being critical for data storage.
Solution Approach 2:
The patent uses auxiliary cells as intermediaries between the wear mechanism and the detection system. These intermediary cells experience the same programming and erasing operations as memory cells but are specifically designated for monitoring purposes. By measuring threshold voltage on these intermediary auxiliary cells rather than directly on data-holding memory cells, the system achieves accurate deterioration detection while preserving data integrity in the primary storage cells.
Data Source
AI summary
An operating method of a non-volatile memory device having a string including a plurality of memory cells and a plurality of auxiliary cells, the plurality of memory cells and the plurality of auxiliary cells being connected in series, includes detecting a threshold voltage of at least one of the plurality of auxiliary cells and generating an output signal corresponding to a deterioration level of the plurality of memory cells, based on the threshold voltage.