Memory System Optimal Threshold Voltage Identification
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Solution Overview
Problem
Current memory systems face challenges in identifying optimal threshold voltages, which are crucial for distinguishing 0s and 1s, leading to potential failure of error correction operations and degraded performance, especially in non-volatile memory systems like NAND flash, where improper threshold voltages can result in incorrect data decoding and increased power consumption.
Innovation Solution
A semiconductor memory system that generates a training sequence with evenly distributed 1s and 0s, which is written alongside user data, analyzed to identify optimal threshold voltages, and used to enhance the functionality of Error Correction Codes (ECC) engines, thereby improving data reliability and system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a training sequence is written alongside user data to identify optimal threshold voltages, then data reliability and decoding accuracy are improved, but memory space is consumed and write/read time increases
Solution Approach 1:
The patent applies preliminary action by writing a training sequence alongside user data during the initial write operation. This training sequence is analyzed later to identify optimal threshold voltages, which are then stored for future use. This approach prepares the system in advance, eliminating the need for time-consuming threshold voltage searches during subsequent read operations, thus improving data reliability while minimizing time loss.
Solution Approach 2:
The patent uses copying by creating a copy of known training data (the training sequence) that is written alongside user data. This training sequence serves as a reference copy that can be analyzed to determine threshold voltages without needing to re-analyze actual user data, thereby improving reliability while maintaining efficient processing time.
2Measurement precision
If threshold voltage identification is performed through sequence analysis, then decoding accuracy is improved, but processing complexity and power consumption increase
Solution Approach 1:
The patent performs threshold voltage identification in advance by analyzing the training sequence during an initial operation. The optimal threshold voltages identified through this preliminary analysis are then stored and reused for subsequent read operations. This eliminates the need for repeated complex analysis, thereby maintaining high measurement precision while significantly reducing power consumption in ongoing operations.
Solution Approach 2:
The system performs self-service by using the training sequence to automatically identify and store its own optimal threshold voltages. This self-configuration eliminates the need for external calibration or repeated analysis, reducing processing complexity and power consumption while maintaining high decoding accuracy through accurate threshold voltage identification.
3Reliability
If error correction operations use optimal threshold voltages, then error correction effectiveness is improved, but the time required for voltage identification and processing increases
Solution Approach 1:
The patent identifies optimal threshold voltages in advance through training sequence analysis and stores them for future use. During error correction operations, these pre-identified threshold voltages are directly applied without requiring re-identification, thereby maintaining high error correction effectiveness while significantly improving processing speed and productivity in subsequent operations.
Data Source
AI summary
A semiconductor memory system and an operating method thereof include a memory device; and a memory controller including a sequence generator, a sequence analyzer, and a processor coupled to the memory device and containing instructions executed by the processor, and configured to generate a sequence by the sequence generator, wherein the sequence comprises a sequence of digital data, write the sequence associated with a user data to the memory device, read out a read data including the sequence and the associated user data, analyze the sequence to understand characters of the read data and create analysis result by the sequence analyzer, identify an optimal threshold voltage in accordance with the analysis result, and provide the optimal threshold voltage to an ECC engine.