Storage Controller Read Level Offset Adaptation
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Solution Overview
Problem
Storage devices face challenges in maintaining optimal read voltage levels due to variations in data retention characteristics across different chips, leading to read failures and reduced operation performance.
Innovation Solution
A storage device with a storage controller that applies different defense code parameters and read level offsets based on health index information for each non-volatile memory device, using machine learning to adjust read levels and improve data reliability and performance by dividing chips into groups with tailored read window intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single read voltage level is used for all non-volatile memory devices, then device complexity is reduced, but read reliability deteriorates due to variations in data retention characteristics across different chips
Solution Approach 1:
The patent segments the population of non-volatile memory devices into multiple groups based on their data retention characteristics. Each group is assigned a specific read level offset value, allowing differentiated voltage control. The storage controller determines the group ID for each device and applies appropriate read level offsets from a lookup table, thereby resolving the contradiction between using a single voltage level (simplicity) and using differentiated voltage levels (reliability).
Solution Approach 2:
The patent changes the read voltage level parameter dynamically based on the data retention characteristics of each memory device. By adjusting the read level offset parameter according to the determined group ID, the system adapts the read voltage to match the specific retention characteristics of each device or chip, improving read reliability without requiring complete customization for each device.
2Reliability
If different read voltage levels are applied to each non-volatile memory device, then read reliability is improved, but device complexity increases due to individualized voltage control requirements
Solution Approach 1:
The patent changes the read voltage level parameter dynamically based on the data retention characteristics of each memory device. By adjusting the read level offset parameter according to the determined group ID, the system adapts the read voltage to match the specific retention characteristics of each device, improving read reliability while managing complexity through parameter adaptation rather than structural complexity.
Solution Approach 2:
The patent creates a universal lookup table that maps group IDs to read level offset values, which can be applied across multiple devices. This multi-functional approach allows the same table structure and offset values to serve multiple devices with similar characteristics, reducing the overall complexity compared to individualized control for each device while maintaining improved reliability.
3Reliability
If chip-specific read level offsets are applied, then data retention performance is improved, but manufacturing precision requirements increase due to tighter process control needs
Solution Approach 1:
The patent segments devices into groups based on their retention characteristics, which are influenced by manufacturing variations. By grouping devices with similar characteristics and applying common read level offsets to each group, the patent accommodates manufacturing variations without requiring extremely tight process control for each individual device, thus improving data retention while managing manufacturing precision requirements.
Data Source
AI summary
A storage device and an operating method of the storage device are provided. The storage device comprises a first non-volatile memory device, a second non-volatile memory device, a third non-volatile memory device a storage controller configured to control the first non-volatile memory device, the second non-volatile memory device, and the third non-volatile memory device, control the first non-volatile memory device to extract a first on-cell count value after a first soft erase operation, set first to third read level offsets of the respective first to third non-volatile memory devices based on the respective first to third on-cell count values, select the first to third defense code parameter sets each corresponding to the respective first to third read level offsets, and transmits first to third read commands based on the selected respective first to third defense code parameter sets to the respective first to third non-volatile memory devices.