Memory Sector Erase Detection Using ECC Error Thresholds
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor memory devices face challenges in accurately determining the erased state of memory sectors due to limitations in error correction capabilities, leading to inefficiencies in data reading and storage operations.
Innovation Solution
The method involves reading data from memory cells, determining the number of cells in a non-erased state, and using an ECC engine to correct errors, thereby determining the sector's erased status based on the number of correctable errors, ensuring accurate sector status indication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of non-erased memory cells exceeds the error correction capabilities of the ECC engine, then the sector status determination becomes uncertain, but data errors increase
Solution Approach 1:
The patent performs a preliminary read operation to count the number of non-erased memory cells in a sector before attempting full data retrieval. This preliminary action allows the system to predict whether the sector's error count will exceed ECC correction capabilities, enabling proactive decision-making about whether to attempt reading the sector or mark it as erased, thereby preventing data errors while maintaining accurate sector status determination
Solution Approach 2:
The patent introduces an intermediary counting mechanism that samples memory cells to estimate the total number of non-erased cells in a sector. This intermediary approach provides a reliable indicator of sector status without requiring full sector reading, allowing the system to accurately determine sector status while avoiding the data errors that would occur from attempting to read sectors with excessive errors
2Measurement precision
If all memory cells are read to accurately determine sector status, then measurement precision improves, but operation time increases
Solution Approach 1:
The patent applies partial action by reading only a subset of memory cells in a sector (e.g., one cell per page or a sampled portion) rather than all cells. This partial reading provides sufficient information to accurately determine sector status through error counting and comparison with thresholds, while significantly reducing the time required compared to reading the entire sector
Solution Approach 2:
The patent segments the sector reading process into multiple pages and performs selective reading of representative cells from each page. This segmentation allows the system to gather comprehensive information about sector status across the entire sector structure without the time penalty of reading every cell, maintaining measurement precision while reducing operation time
Data Source
AI summary
The present disclosure includes methods, devices, modules, and systems for operating semiconductor memory. A number of method embodiments include reading data from memory cells corresponding to a sector of data, determining a number of the memory cells in a non-erased state, and, if the number of the memory cells in a non-erased state is less than or equal to a number of errors correctable by an ECC engine, determining the sector is erased.