Flash Memory Controller Probabilistic Error Correction
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Solution Overview
Problem
Flash memory devices storing multiple data bits per cell face increased error bits due to overlapping threshold voltage distributions, necessitating efficient error detection and correction methods without increasing chip size.
Innovation Solution
A memory system incorporating a controller and memory device that uses probabilistic information generation and error correction blocks to update and apply error correction based on read data, allowing for efficient error correction without expanding chip size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multi-bit data is stored per cell to increase storage capacity, then storage density is improved, but error rate increases due to overlapping threshold voltage distributions
Solution Approach 1:
The patent applies preliminary action by performing multiple read operations and updating probabilistic information before final error correction. The controller reads data multiple times, updates probability distributions based on each read, and only then performs error correction using the accumulated probabilistic information, thereby improving reliability before data is considered final
Solution Approach 2:
The patent implements feedback by using read data to update probabilistic information, which then feeds back into the error correction process. The controller uses the outcome of each read operation to refine probability distributions, which are subsequently used to improve error correction accuracy in later operations
2Reliability
If error correction operations are performed multiple times to improve data reliability, then reliability is improved, but processing time increases
Solution Approach 1:
The patent performs preliminary probabilistic information updates during the read process itself, before final error correction is needed. By accumulating probability data during multiple reads and preparing correction information in advance, the system reduces the time required for final error correction while maintaining high reliability
Solution Approach 2:
The patent maintains continuous useful action by overlapping the probabilistic information update process with the read operations. Instead of performing error correction as a separate sequential step, the system continuously updates probability distributions during reads, ensuring that error correction is always ready when needed without adding significant delay
Data Source
AI summary
A memory system is provided. The memory system includes a memory device suitable for reading out data from memory cells by a plurality of read voltages having various levels, and a controller suitable for updating probabilistic information based on the read out data when the read out data is input to the controller, and performing an error correction operation by the updated probabilistic information, wherein the controller updates the probabilistic information a predetermined number of times that the memory device reads out the data.