Memory Management via Voltage Offset Detection
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Solution Overview
Problem
Conventional memory management methods for rewritable non-volatile memory modules rely on program erase cycle counts to determine wear leveling operations, which may overlook aged physical units with low cycle counts, leading to reduced service life and data safety.
Innovation Solution
A memory management method and storage controller that perform a checking operation on physical units based on voltage offset values between optimization and preset read voltage sets, or Gray code count offset values, to accurately determine the need for memory management operations without relying on program erase cycle counts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wear leveling operation is determined based on program erase cycle count, then the operation can be triggered when a threshold is exceeded, but aged physical units with low cycle counts may be overlooked, reducing service life
Solution Approach 1:
The patent changes the detection parameter from program erase cycle count to voltage offset value. By measuring the offset between read voltages at different word lines, the system can directly detect physical aging effects without relying on usage history, thereby improving the accuracy of aging detection and ensuring aged units are not overlooked.
Solution Approach 2:
The patent replaces the mechanical counting method (tracking program erase cycles) with an electrical measurement method (measuring voltage offset). This substitution allows direct detection of physical aging through electrical characteristics, providing more accurate identification of aged physical units regardless of their program erase cycle count.
2Reliability
If conventional threshold-based wear leveling is used, then implementation is simple, but it cannot truly manage aged physical units, leading to reduced space and service life
Solution Approach 1:
The patent segments the memory module into multiple physical units and further into word lines within each physical unit. By performing voltage offset measurements on individual word lines and comparing them against thresholds, the system can identify aged units with precision while maintaining a structured, manageable checking process.
Solution Approach 2:
The patent introduces voltage offset value as a new parameter for detecting aging, replacing the simple cycle count threshold. This parameter change enables more accurate identification of aged units, improving data safety while the segmented word-line approach keeps the implementation complexity manageable.
Data Source
AI summary
A memory management method for a storage device having a rewritable non-volatile memory module is provided, wherein the rewritable non-volatile memory module has a plurality of physical units, and each of the physical units has a plurality of word-lines. The method includes: performing a first checking operation on a target physical unit among the physical units according to an occurrence of a specific event; and determining whether a first operation needs to be performed on valid data in the target physical unit according to a checking result of the first checking operation that corresponds to the target physical unit.