Non-Volatile Memory Read Level Inference via Valley Search Model
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Solution Overview
Problem
The existing memory devices face performance degradation due to the time-consuming valley search operation required for improving read reliability, which increases read time and degrades read performance.
Innovation Solution
A non-volatile memory device that employs a machine learning model to infer read levels by performing a valley search sensing operation on the distribution of threshold voltages, reducing the need for repetitive valley searches and optimizing read operations through a read information model trained with valley search detection information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a valley search operation is performed on the distribution of threshold voltages of memory cells to improve read reliability, then read reliability is improved, but read time increases and read performance is degraded
Solution Approach 1:
The patent performs valley search operations in advance during idle periods or background processes to pre-determine optimal read levels. This preliminary action stores the results for future read operations, eliminating the need to perform time-consuming valley searches during actual data retrieval, thus resolving the contradiction between ensuring read reliability and maintaining fast read performance
Solution Approach 2:
The patent creates a copy of the threshold voltage distribution characteristics through valley search and stores this information separately. Instead of repeatedly performing the full valley search operation during each read, the system uses the copied valley information to quickly determine read levels, maintaining reliability while significantly reducing read time
2Reliability
If a valley search operation is performed on the distribution of threshold voltages of memory cells to improve read reliability, then read reliability is improved, but read performance is degraded
Solution Approach 1:
The patent performs valley search operations in advance during idle periods or background processes to pre-determine optimal read levels. This preliminary action stores the results for future read operations, eliminating the need to perform time-consuming valley searches during actual data retrieval, thus resolving the contradiction between ensuring read reliability and maintaining fast read performance
Solution Approach 2:
The patent creates a copy of the threshold voltage distribution characteristics through valley search and stores this information separately. Instead of repeatedly performing the full valley search operation during each read, the system uses the copied valley information to quickly determine read levels, maintaining reliability while significantly reducing read time
Data Source
AI summary
A non-volatile memory device includes a memory cell array including memory cells, a page buffer circuit including page buffers respectively connected to bit lines, a buffer memory, and a control logic configured to control a read operation on the memory cells. In the read operation, the control logic obtains valley search detection information including read target block information and word line information by performing a valley search sensing operation on a distribution of threshold voltages of the memory cells, obtains a plurality of read levels using a read information model by inputting the valley search detection information into the read information model, and performs a main sensing operation for the read operation.