Non-linear Refresh Mechanism for Dense Memory Data Integrity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As memory devices become denser, the reduction in threshold voltage separation leads to increased charge loss rates, resulting in higher data corruption rates and performance issues over time.
Innovation Solution
Implementing a non-linear refresh operation timing pattern, such as logarithmic, for memory devices like NAND Flash, and adjusting discharge timings across word lines using a staggered discharge method to maintain charge integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory devices are made denser to increase storage capacity, then storage capacity is improved, but threshold voltage separation decreases leading to increased charge loss and data corruption
Solution Approach 1:
The patent applies preliminary action by performing refresh operations before charge loss becomes critical. The system proactively refreshes memory blocks based on predicted charge retention models, preventing data corruption before it occurs rather than reacting after errors manifest. This is achieved through advance timing of refresh cycles based on charge retention characteristics of the specific memory block.
Solution Approach 2:
The patent changes the timing parameter of refresh operations from uniform fixed intervals to non-uniform intervals based on charge retention models. Different memory blocks receive refresh at different times according to their specific charge retention characteristics, optimizing the balance between preventing charge loss and minimizing unnecessary refresh operations that could cause wear.
2Ease of manufacture
If uniform refresh timing is used for all memory blocks, then implementation is simple, but charge loss compensation is insufficient for blocks with different retention characteristics
Solution Approach 1:
The patent applies local quality by tailoring refresh timing to individual memory blocks based on their specific charge retention characteristics. Each memory block receives customized refresh intervals rather than a uniform schedule, optimizing charge retention accuracy for each block's unique properties while maintaining overall system reliability.
Data Source
AI summary
Methods, apparatuses and systems related to maintaining stored data are described. The apparatus may be configured to refresh the stored data according to schedule that includes different delays between successive refresh operations.