Memory Self-Refresh Counter Reset for Row Hammer Protection
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Solution Overview
Problem
As memory components decrease in size, the density of memory cells increases, leading to a higher rate of data degradation in nearby cells due to repeated access, known as the row hammer effect, necessitating effective identification and refresh of victim rows to prevent unnecessary refresh operations.
Innovation Solution
Implementing a counter reset detector circuit that clears or resets access count values during self-refresh mode, ensuring potential victim rows are refreshed along with would-be aggressor rows, thereby reducing the need for targeted refreshes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If access count values are maintained to identify victim rows, then the ability to prevent data degradation is improved, but the complexity of tracking and managing counters increases
Solution Approach 1:
The memory device performs self-refresh operations automatically without external intervention. The counter reset detector circuit automatically identifies when to reset access counts during self-refresh cycles, eliminating the need for external controller involvement in the counter management process.
Solution Approach 2:
The system performs preliminary refresh operations before actual data degradation occurs. By monitoring access counts and triggering self-refresh cycles in advance, the system prevents row hammer effects before they cause data loss, rather than reacting after degradation has occurred.
2Reliability
If targeted refresh operations are performed based on access counts, then data degradation is reduced, but unnecessary refresh operations increase
Solution Approach 1:
The refresh strategy dynamically adjusts based on real-time access count monitoring. The counter reset detector circuit continuously monitors access patterns and automatically triggers self-refresh operations only when necessary, transitioning from static refresh schedules to dynamic, demand-driven refresh operations.
Solution Approach 2:
The system implements feedback through the counter reset detector circuit that monitors access counts and triggers self-refresh operations based on actual usage patterns. This closed-loop feedback mechanism ensures refresh operations are performed only when access counts indicate potential data degradation risk.
3Use of energy by moving object
If self-refresh mode is implemented, then power consumption is reduced, but access count values may become inaccurate
Solution Approach 1:
The system performs preliminary counter reset actions at the beginning of self-refresh cycles. By resetting access counts before the self-refresh operation starts, the system ensures accurate counting for the next period of operation, preventing accumulation errors during the refresh process.
Solution Approach 2:
The patent replaces complex mechanical counter management with a simpler electronic detection and reset mechanism. The counter reset detector circuit uses electronic signal detection during self-refresh cycles to automatically manage counter values, substituting complex software-based counting with hardware-based electronic detection.
Data Source
AI summary
Apparatuses, systems, and methods for clearing or resetting an access count value during a self-refresh mode. Various patterns of access to a row, sometimes called an aggressor row, may cause an increased rate of information decay in memory cells along nearby word lines, at which point they may be referred to as victim rows. Aggressor rows are identified by their access counts so that victim rows may be refreshed to prevent information decay. A memory may be placed in a self-refresh mode. During the self-refresh mode, a counter reset detector circuit clears or resets the access count value stored in counter memory cells associated with each address as it is refreshed. In this manner, potential victim rows are refreshed during the self-refresh mode along with would-be aggressor rows and fewer targeted refreshes may be issued.