Memory Controller Dynamic Read Voltage Estimation
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Solution Overview
Problem
Existing memory systems face challenges in accurately determining optimal read voltages, leading to errors in data retrieval due to changes in channel characteristics over time or due to program/erase cycles, which affects data retention and reliability.
Innovation Solution
A memory system and method that includes a memory controller capable of estimating optimal read voltages by analyzing threshold voltage distributions and reflecting channel characteristics, using a threshold voltage distribution checker, optimal read voltage determiner, and optimal read voltage estimator to adjust read voltages accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed read voltages are used in memory systems, then device complexity is reduced, but data retrieval accuracy deteriorates due to channel characteristic changes
Solution Approach 1:
The patent implements dynamic read voltage adjustment by continuously monitoring threshold voltage distributions and adapting read voltages to current channel characteristics. The memory controller dynamically determines optimal read voltages based on real-time threshold voltage distribution analysis, transforming the static read voltage approach into a dynamic adaptation system that responds to channel characteristic changes.
Solution Approach 2:
The patent employs feedback mechanisms where the memory controller monitors threshold voltage distributions and uses this information to adjust read voltages. The system continuously measures channel characteristics through threshold voltage distribution analysis and feeds this information back to optimize read voltage selection, creating a closed-loop control system that maintains data retrieval accuracy despite channel variations.
2Measurement precision
If optimal read voltages are continuously adjusted to reflect channel characteristics, then data retrieval accuracy is improved, but device complexity increases
Solution Approach 1:
The patent implements self-service through automatic threshold voltage distribution analysis and optimal read voltage determination. The memory controller autonomously monitors channel characteristics and adjusts read voltages without requiring external intervention or complex external control systems. The system serves itself by using its own threshold voltage distribution data to optimize its reading operations.
Solution Approach 2:
The patent performs preliminary analysis of threshold voltage distributions to determine optimal read voltages before actual data retrieval operations. By pre-characterizing the channel state through threshold voltage distribution measurement and calculating optimal read voltages in advance, the system prepares the optimal reading parameters ahead of time, reducing the complexity of real-time voltage adjustment during data retrieval.
3Reliability
If read voltages are adapted to current channel characteristics, then data retention reliability is improved, but measurement and detection difficulty increases
Solution Approach 1:
The patent replaces complex physical measurements with electrical characteristic analysis. Instead of directly measuring channel characteristics through complex physical probes, the system uses electrical measurements of threshold voltage distributions to infer channel state. This substitution of measurement approaches simplifies the detection process while maintaining reliability.
Solution Approach 2:
The patent introduces threshold voltage distribution analysis as an intermediary measurement approach. Rather than directly measuring channel characteristics, the system uses threshold voltage distributions as an intermediate parameter that reflects channel state. This intermediary measurement provides a practical and manageable way to assess channel characteristics and determine optimal read voltages.
Data Source
AI summary
Provided herein may be a memory system and a method of operating the same. The memory system may include a memory device including memory cells, each having any one of an erased state or one of a plurality of programmed states, and a memory controller configured to estimate an optimal read voltage associated with at least one of the erased state or one of the programmed states based on a threshold voltage distribution corresponding to at least one of the programmed states. The memory controller may include a threshold voltage distribution checker configured to check a first threshold voltage distribution corresponding to a first programmed state, among the programmed states, and determine an average threshold voltage of the first threshold voltage distribution, and an optimal read voltage estimator configured to estimate a second optimal read voltage corresponding to a second side of the first threshold voltage distribution.