Memory Controller Read Voltage Estimation
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Solution Overview
Problem
In memory systems, especially those with multi-level cell memory blocks, there is a challenge in accurately selecting read voltages to ensure successful data retrieval due to changes in threshold voltage distributions over time, leading to potential errors and reduced performance.
Innovation Solution
A controller that estimates values of unused read voltages in a read voltage set based on successfully used voltages during a read operation and updates the read voltage set, ensuring the latest threshold voltage distribution is incorporated, thereby improving the probability of successful error correction and system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If read voltage sets are updated using only actually used read voltages, then the update process is simple and fast, but the accuracy of voltage estimation for unused voltages deteriorates
Solution Approach 1:
The system uses the actually used read voltages to automatically estimate the unused read voltages through interpolation algorithms, making the voltage set self-updating without external intervention. The used voltages serve dual purposes: both for the read operation and for generating estimates of unused voltages.
Solution Approach 2:
The patent changes the parameter values of unused read voltages by estimating them based on the relationship between used voltages. The estimation algorithm calculates new voltage values that reflect the latest threshold voltage distribution, thereby adapting the voltage parameters to current memory conditions.
2Measurement precision
If all read voltages are measured and updated in every read operation, then the voltage set remains highly accurate, but the complexity and time consumption increase
Solution Approach 1:
Instead of measuring and updating all read voltages, the system performs partial updates by only actually measuring the used voltages and estimating the unused ones. This partial action approach maintains sufficient accuracy while reducing complexity.
Solution Approach 2:
The patent introduces an estimation algorithm as an intermediary that bridges the gap between used and unused voltages. This intermediary component derives the missing voltage values from the available measurements, avoiding the need for direct measurement of all voltages.
3Ease of operation
If read voltage sets are not updated dynamically, then the system operation is simple, but the reliability of data retrieval deteriorates due to threshold voltage distribution changes
Solution Approach 1:
The system implements feedback by using the results of actual read operations (used voltages) to update the complete read voltage set. This feedback loop ensures that the voltage set continuously adapts to threshold voltage distribution changes while maintaining operational simplicity.
Solution Approach 2:
The patent performs preliminary estimation of unused voltages based on used voltages before actual read operations. This preliminary action prepares an updated voltage set in advance, improving reliability without adding complexity during the critical read operation phase.
Data Source
AI summary
A controller for controlling a memory device comprising a plurality of multi-level cell memory blocks, the controller includes: a processor suitable for controlling the memory device to perform a read operation on a target logical page using some of the plurality of read voltages in a selected read voltage set; and an error correction code (ECC) component suitable for determining whether the read operation is successful, by performing error detection and correction on data generated in the read operation and output from the memory device, wherein, when the read operation is determined to be successful, the processor updates the selected read voltage set with the read voltages used in the read operation when it is successful and estimated values of unused read voltages of the selected read voltage set, the estimated values being determined based on the used read voltages.