Read Voltage Control for Memory Storage Devices
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Solution Overview
Problem
Conventional read voltage adjustment mechanisms in memory storage devices fail to correctly correct read voltage levels as memory cells wear out, leading to incorrect data retrieval and shortened device lifespan due to shifting threshold voltage distributions.
Innovation Solution
A read voltage control method that adjusts the read voltage level based on adjustment information obtained from the data and channel parameters of memory cells, using a first read command sequence to determine the initial voltage level and subsequently adjusting it to improve correction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional preset read voltage levels are used to read data from memory cells, then the reading operation is simple and fast, but the read voltage levels become severely shifted as memory cells wear out, leading to incorrect data retrieval
Solution Approach 1:
The patent implements a feedback mechanism where the memory controller reads test data from memory cells using preset read voltage levels, calculates adjustment information based on the test data and channel parameters (such as read disturbance count and program/erase cycle count), and then adjusts the read voltage levels accordingly. This closed-loop feedback system ensures that the read voltage levels are continuously optimized to match the actual threshold voltage distribution of the memory cells, thereby maintaining high data retrieval accuracy even as the memory device ages and undergoes wear.
2Reliability
If read voltage levels are adjusted frequently to compensate for memory cell wear, then data retrieval accuracy is maintained, but the complexity and computational overhead of the adjustment mechanism increases
Solution Approach 1:
The patent changes the parameters used for voltage adjustment from simple preset levels to dynamic adjustment based on multiple factors including channel parameters (read disturbance count, program/erase cycle count) and test data characteristics. By adjusting the read voltage levels according to these changing parameters, the system maintains accurate data retrieval while optimizing the correction process to be computationally efficient and adaptable to different wear states of the memory cells.
Data Source
AI summary
An exemplary embodiment of the invention provides a read voltage control method for a rewritable non-volatile memory module. The method includes: sending a first read command sequence which instructs a reading of a plurality of first memory cells by using a first voltage level to obtain first data; obtaining first adjustment information of a read voltage according to the first data and a channel parameter of the first memory cells, and the channel parameter reflects a channel status of the first memory cells; and adjusting a voltage level of the read voltage from the first voltage level to a second voltage level according to the first adjustment information.