NAND Memory Read Scrub Using Page Location-Based Voltage Prediction
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Solution Overview
Problem
The charge stored in NAND-type memory cells changes over time and with repeated read operations, affecting the correctness of data reading, and existing read scrub operations can be inefficient and resource-intensive, leading to performance degradation.
Innovation Solution
A memory system that includes a memory controller capable of obtaining and storing parameters for generating target reference voltages based on a preset model, using a location relationship between physical pages to optimize read operations, reducing the need for extensive retry operations and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional read scrub operations are performed on all physical pages, then data reading reliability is improved, but system performance and resource efficiency deteriorate
Solution Approach 1:
The patent segments the read scrub operation by dividing physical pages into different groups based on their location relationships. Instead of uniformly processing all physical pages, the system selectively applies read scrub operations to specific groups (e.g., first physical pages vs. second physical pages), thereby reducing the overall operation scope while maintaining data reliability for critical pages.
Solution Approach 2:
The patent implements local quality by applying different read scrub strategies to different physical page groups based on their characteristics and location relationships. First physical pages receive full read scrub operations for high reliability, while second physical pages use optimized operations based on their location relationship with first pages, achieving resource efficiency without compromising overall data integrity.
2Reliability
If read scrub operations are performed frequently to maintain data integrity, then data correctness is improved, but resource consumption and operation time increase
Solution Approach 1:
The patent performs preliminary actions by establishing location relationships between physical pages in advance and pre-determining which pages require read scrub operations. By pre-classifying physical pages into different groups based on their location relationships, the system avoids performing unnecessary read scrub operations on pages that can be inferred to be reliable, thereby reducing operation time while maintaining data correctness.
Solution Approach 2:
The patent enables self-service by using the location relationship information of physical pages to automatically determine which pages need read scrub operations. The system leverages the inherent spatial relationships between pages to self-identify candidates for read scrub, eliminating the need for exhaustive checking of all pages and reducing overall operation time.
3Measurement precision
If extensive retry operations are performed to correct reading errors, then data reading accuracy is improved, but resource consumption increases
Solution Approach 1:
The patent applies preliminary anti-action by performing read scrub operations on specific physical page groups before actual read operations to prevent reading errors. By proactively identifying and correcting potential errors in first physical pages and selectively in second physical pages based on location relationships, the system reduces the need for extensive retry operations, thereby lowering resource consumption while maintaining reading accuracy.
Solution Approach 2:
The patent implements feedback mechanisms by using the results of read scrub operations on first physical pages to inform and optimize read operations on second physical pages. The location relationship information serves as feedback that allows the system to adjust its reading strategy, reducing unnecessary retry operations on pages that are likely to read correctly based on their relationship with previously verified pages.
Data Source
AI summary
The examples of the present disclosure discloses a memory system and an operation method thereof, a memory controller and a storage medium, and the memory system comprises a memory device comprising a plurality of word lines, a plurality of storage units coupled to the same word line form at least one physical page; the memory controller is configured to: obtain a first parameter of a first physical page of the plurality of physical pages in a process of performing a read scrub operation; generate a first parameter of the second physical page according to the first parameter of the first physical page in combination with a location relationship of the second physical page and the first physical page; and store the first parameter of the first physical page and the first parameter of the second physical page.