Memory Controller Adaptive Empty-Page Scanning for Error-Prone Word Lines
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Solution Overview
Problem
Conventional memory sub-systems perform empty page scanning operations with a fixed frequency across all memory blocks, leading to inefficiencies as certain blocks are prone to fewer errors, resulting in wasteful and slow memory operations.
Innovation Solution
A memory sub-system controller tailors the frequency of empty page scanning based on the quantity of errors detected in previous scans, focusing on word lines with lower erasure reliability, reducing unnecessary scans and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed frequency empty page scanning is performed across all memory blocks, then reliability of error detection is improved, but productivity and operational efficiency deteriorate due to unnecessary scans on error-free blocks
Solution Approach 1:
The patent applies local quality by transitioning from uniform scanning across all memory blocks to differentiated scanning based on individual block characteristics. Specifically, the system identifies blocks with higher error rates and concentrates scanning resources on those blocks, while reducing or eliminating scans on blocks with lower error rates. This localized approach maintains reliability where needed while improving overall productivity by avoiding unnecessary operations on healthy blocks.
Solution Approach 2:
The patent implements dynamics by making the scanning frequency adaptive rather than static. The system dynamically adjusts the scanning frequency for each memory block based on historical error data and current block status. Blocks exhibiting error patterns receive increased scanning frequency, while stable blocks receive reduced frequency, allowing the system to respond to changing conditions and optimize the balance between reliability and productivity over time.
2Measurement precision
If comprehensive empty page scanning is performed on all word lines, then measurement precision of memory status is improved, but loss of time and operational speed worsen
Solution Approach 1:
The patent applies the extraction principle by selectively removing unnecessary scanning operations from the system. Instead of scanning all word lines uniformly, the system extracts and identifies the subset of word lines that are actually prone to errors based on historical data and block characteristics. Scanning is then concentrated only on these identified problematic word lines, maintaining measurement precision for critical areas while eliminating time-wasting scans on healthy word lines.
Solution Approach 2:
The patent implements partial action by performing scanning operations only on the necessary portion of memory blocks rather than the entire memory space. The system identifies and targets specific blocks or word lines that require monitoring, applying scanning resources partially rather than comprehensively. This approach maintains adequate measurement precision for error-prone areas while significantly reducing the total time consumed by scan operations.
Data Source
AI summary
Aspects of the present disclosure configure a system component, such as memory sub-system controller, to perform empty page scan operations. The controller selects a portion of the set of memory components that is empty and ready to be programmed. The controller reads one or more signals from the selected portion of the set of memory components. The controller generates an error count value representing whether the portion of the set of memory components is valid for programming based on a result of reading the one or more signals from the selected portion. The controller updates a scan frequency for performing the empty page scan operations for the portion of the set of memory components based on the error count value.