Memory Controller Soft-Decoding for Degraded Threshold Voltages
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Memory systems face challenges in maintaining error correction accuracy when threshold voltage distributions of memory cells degrade, leading to decreased efficacy of soft-decision decoding.
Innovation Solution
A memory controller is configured to perform soft-decision decoding using multiple threshold voltage sections, with sizes determined based on optimum read voltages and reliability values, to enhance error correction even in degraded voltage distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If soft-decision decoding is performed using fixed threshold voltage sections, then the decoding process is simple, but error correction accuracy decreases when threshold voltage distributions are degraded
Solution Approach 1:
The patent implements dynamic adjustment of threshold voltage section sizes based on detected voltage distribution characteristics. The memory controller adapts the section sizes to match the actual threshold voltage distributions of memory cells, transforming a static decoding approach into a dynamic one that responds to changing conditions, thereby maintaining high error correction accuracy without excessive complexity
Solution Approach 2:
The patent changes the parameters of threshold voltage sections (specifically their sizes) based on detected voltage distribution characteristics. By adjusting these parameters dynamically, the system optimizes error correction performance for different memory cell states and degradation levels, resolving the contradiction between accuracy and complexity
2Reliability
If uniform threshold voltage sections are used for soft-decision decoding, then the implementation is straightforward, but correction efficacy decreases when voltage distributions are degraded
Solution Approach 1:
The patent applies different threshold voltage section sizes to different regions of the voltage distribution based on local characteristics. Instead of using a uniform approach, the system tailors the section sizes to match the specific properties of each voltage region, improving correction efficacy by addressing local variations in the degraded voltage distributions
3Measurement precision
If threshold voltage sections are adjusted to match degraded distributions, then error correction accuracy improves, but the system complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the memory controller detects the actual threshold voltage distributions of memory cells and uses this information to adjust the threshold voltage section sizes. This closed-loop approach ensures that the sections are continuously optimized to match the current state of the memory cells, improving data read accuracy while managing complexity through adaptive control
Data Source
AI summary
A memory system, a memory controller and a method for operating a memory system are disclosed. Specifically, by performing soft-decision decoding for data read from some of the plurality of memory cells based on a first optimum read voltage of one or more optimum read voltages, based on reliability values of one or more first threshold voltage sections, and one or more second threshold voltage sections and also based on the first and second threshold voltage sections, it is possible to provide a memory system, a memory controller and a method for operating a memory system, capable of increasing an error correction effect by soft-decision decoding even in the case where threshold voltage distributions of memory cells in which data is stored are degraded.