Non-volatile Memory Read Voltage Selection
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Solution Overview
Problem
Non-volatile memory devices face challenges in successfully reading data due to data degradation or interference from read and program disturbs, especially when using fixed read voltages, which can lead to unsuccessful decoding of codewords.
Innovation Solution
A non-volatile memory device with a controller that establishes a standard table of indexes corresponding to different read voltages, performs error check corrections, and creates a priority table to optimize read operations by iteratively selecting the most effective read voltage for decoding codewords, increasing the probability of successful decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed read voltage is utilized to read data, then the read operation is simple and fast, but the non-volatile memory may not be able to read data successfully due to data degradation or interference
Solution Approach 1:
The patent implements dynamic read voltage selection by maintaining multiple read voltages in a read voltage table and selectively applying different read voltages based on the age of stored data and error correction needs, transforming the static fixed voltage approach into a dynamic adaptive system that resolves the contradiction between reliability and complexity
Solution Approach 2:
The patent changes the read voltage parameter based on data retention time and error patterns by storing multiple read voltages with different strengths in the read voltage table, allowing the system to adjust voltage parameters to match the degradation state of stored data, thereby improving successful read probability without excessive complexity
2Reliability
If multiple read voltages are tested iteratively to decode codewords, then the probability of successful decoding increases, but the read time increases
Solution Approach 1:
The patent performs preliminary action by pre-establishing a read voltage table with multiple read voltages ordered by strength before actual read operations, and by implementing error correction coding during write operations, so that during read operations the system can quickly select appropriate voltages without iterative testing, reducing read time while maintaining high decoding success probability
Solution Approach 2:
The patent implements feedback mechanisms by monitoring error correction results and adjusting read voltage selection accordingly, using error patterns from previous reads to inform subsequent voltage choices, and updating the read voltage table based on observed data retention characteristics, thereby optimizing the balance between decoding success and read time
Data Source
AI summary
A non-volatile memory device including a non-volatile memory and a controller is provided. The controller establishes a standard table and at least one priority table according to a read table stored in the non-volatile memory. The probability that the controller utilizes the read voltages corresponding to the indexes recorded in the priority table to read and successfully decode the codewords stored in non-volatile memory is high. When the controller utilizes the read voltages corresponding to the indexes recorded in the priority table to read and unsuccessfully decode the codewords, the controller utilizes the read voltages corresponding to the indexes recorded in the standard table to read and decode the codewords stored in non-volatile memory.