Memory System with Dual Row Hammer Detection
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Solution Overview
Problem
As memory integration increases, the coupling effect between neighboring word lines in memory cells leads to data loss due to 'word line disturbance' or 'row hammering', where frequently activated word lines affect adjacent cells, risking data corruption before refresh.
Innovation Solution
Implement a memory system with separate normal and security areas, utilizing first and second row hammering detection circuits to selectively refresh rows, combined with error correction codes and controlled access methods to protect security data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory integration increases to improve storage capacity, then storage density is improved, but coupling effect between neighboring word lines increases causing row hammering
Solution Approach 1:
The memory system divides the cell array into multiple banks, with each bank independently managed for row activation counting and refresh operations. This segmentation allows localized monitoring and refresh of affected rows without impacting the entire memory array, effectively containing the row hammering effect to specific regions while maintaining high integration density.
Solution Approach 2:
The system performs preliminary detection of row activation frequencies and identifies potentially affected rows before actual data corruption occurs. By counting row activations and proactively refreshing rows that exceed thresholds, the system prevents row hammering damage rather than correcting it after the fact, maintaining data integrity in high-density configurations.
2Reliability
If row hammering detection and refresh operations are implemented to protect data, then data reliability is improved, but memory operation complexity increases
Solution Approach 1:
The memory system incorporates self-monitoring capabilities where row activation counts are automatically tracked and compared against thresholds. The system autonomously identifies rows requiring refresh and executes refresh operations without external intervention, reducing the complexity burden on external controllers while maintaining high data integrity through continuous self-protection.
Solution Approach 2:
Instead of monitoring and refreshing all rows uniformly, the system applies partial action by focusing refresh operations only on rows that exceed activation thresholds or are identified as potentially affected. This selective approach reduces the overall complexity of refresh operations while maintaining adequate protection against row hammering attacks.
3Reliability
If all rows are monitored and refreshed to maximize protection, then security against row hammering is improved, but processing time and energy consumption increase
Solution Approach 1:
The system monitors all rows for activation counts but applies refresh operations selectively only to rows that exceed predefined thresholds or are identified as potentially affected by row hammering. This partial action approach maintains comprehensive security monitoring while minimizing the time and energy expenditure associated with actual refresh operations, avoiding the need to refresh all rows regardless of their vulnerability status.
Solution Approach 2:
The memory array is divided into banks with independent row activation counting and refresh control. This segmentation allows parallel processing of monitoring and refresh operations across different banks, reducing the overall processing time compared to sequential handling of the entire array. Each bank can independently identify and refresh affected rows simultaneously, improving efficiency while maintaining security.
Data Source
AI summary
A memory system includes: a normal memory area suitable for storing normal data; a security memory area suitable for storing security data; a first row hammer detection circuit suitable for sampling and counting a portion of rows that are activated in the normal memory area to select first rows that need to be refreshed; and a second row hammer detection circuit suitable for counting all rows that are activated in the security memory area to select second rows that need to be refreshed.