Memory Refresh Target Selection Circuit for Row Hammering Mitigation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As memory integration increases, the coupling effect between word lines leads to data damage in memory cells due to frequent activation, known as row hammering, where data is deteriorated before memory cell refresh, posing a concern for data integrity.
Innovation Solution
A memory system with a refresh target selection circuit that tracks and updates risk scores for activated rows, increasing scores based on row activations and adjacent row activations, allowing for efficient selection and smart refresh operations to mitigate data loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the spacing between word lines is decreased to increase memory integration, then the memory capacity increases, but the coupling effect between neighboring word lines increases causing row hammering
Solution Approach 1:
The patent applies preliminary action by proactively identifying rows that are likely to suffer from row hammering before data corruption occurs. The refresh target selection circuit continuously monitors row activation patterns and pre-selects candidate rows for refresh based on their activation frequency and neighboring row activity, performing refresh operations before the coupling effect causes data damage.
Solution Approach 2:
The patent implements feedback through the refresh target selection circuit that monitors row activation patterns and uses this information to dynamically select refresh targets. The circuit receives feedback about which rows are frequently activated and which neighboring rows are activated, and uses this feedback to prioritize refresh operations on rows at risk of row hammering, creating a closed-loop system that adapts to actual usage patterns.
2Reliability
If frequent refresh operations are performed on all rows to prevent data loss, then data integrity is maintained, but memory operation efficiency decreases
Solution Approach 1:
The patent applies local quality by differentiating refresh requirements among different rows rather than uniformly refreshing all rows. The refresh target selection circuit identifies specific rows that are candidates for refresh based on their individual activation patterns and neighboring row activity, applying refresh operations only where needed. This selective approach maintains data integrity for vulnerable rows while avoiding unnecessary refresh operations on other rows, thereby preserving memory operation efficiency.
3Measurement precision
If the refresh target selection circuit monitors all row activations to accurately identify at-risk rows, then row hammering detection accuracy increases, but circuit complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the monitoring function into focused components that track specific aspects of row activation. Rather than monitoring all rows comprehensively, the refresh target selection circuit segments the monitoring task to focus on identifying frequently activated rows and their neighboring rows, using this segmented information to select refresh targets. This segmentation reduces the complexity burden while maintaining sufficient detection accuracy for row hammering prevention.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively identifies and prioritizes rows for refresh based on risk scores, reducing data deterioration from row hammering by strategically targeting rows with high likelihood of data loss during smart refresh operations.
Implementation Method 1
As the spacing between word lines decreases, the coupling effect between the neighboring word lines increases
Data Source
AI summary
A memory core including a memory core including memory cells that are arranged in a plurality of rows and a plurality of columns; and a refresh target selection circuit suitable for storing an address and a risk score of each of activated rows among the rows, wherein the refresh target selection circuit is further suitable for increasing the risk score of a corresponding row whenever the corresponding row is activated, whenever a row at a ‘+2’ position of the corresponding row is activated, and whenever a row at a ‘−2’ position of the corresponding row is activated.