Refresh Control Device for Row Hammer Mitigation in Memory Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As memory integration density increases, the reduced pitch between word lines in memory devices leads to a coupling effect known as word line disturbance, causing data deterioration and loss due to row hammering, where frequently activated word lines affect adjacent memory cells, resulting in data damage before refresh can occur.
Innovation Solution
A refresh control device is introduced that decodes command signals to generate refresh, active, and row hammer refresh signals, combining these to produce a refresh control signal that manages addresses and performs targeted refresh operations to prevent data loss by distinguishing between normal and row hammer refresh modes, reducing the frequency of refresh operations and optimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the pitch between word lines is reduced to increase integration density, then memory integration density is improved, but word line disturbance and row hammering occur causing data deterioration
Solution Approach 1:
The refresh control device performs preliminary detection of row hammering conditions by monitoring access patterns to word lines. When a word line is detected to be frequently accessed, the device proactively activates adjacent word lines for refresh before data deterioration occurs, preventing row hammering effects rather than reacting after damage has occurred.
Solution Approach 2:
The refresh control device acts as an intermediary between the memory controller and memory cells. It intercepts refresh commands, analyzes them to detect row hammering patterns, and modifies the refresh operations by selectively activating adjacent word lines. This intermediary function allows the system to maintain high integration density while preventing data deterioration through intelligent refresh control.
2Reliability
If refresh operations are performed frequently to prevent data loss, then data integrity is improved, but power consumption increases
Solution Approach 1:
Instead of performing uniform refresh operations across all word lines, the refresh control device applies local quality by selectively refreshing only those word lines that are adjacent to frequently accessed word lines. This targeted approach maintains data integrity in vulnerable regions while avoiding unnecessary refresh operations in other regions, thereby reducing overall power consumption.
Solution Approach 2:
The refresh control device dynamically changes the refresh parameters based on detected access patterns. When row hammering is detected, it adjusts the refresh frequency and scope for specific adjacent word lines. This parameter adaptation allows the system to maintain data integrity only where needed, reducing power consumption compared to frequent universal refresh operations.
3Reliability
If adjacent word lines are selectively activated for refresh to prevent row hammering, then data deterioration is prevented, but device complexity increases
Solution Approach 1:
The refresh control device segments the refresh control function into distinct components: a detection unit that identifies frequently accessed word lines, and a refresh control unit that activates adjacent word lines. This segmentation allows the complex row hammering prevention function to be implemented through modular logic, managing device complexity while maintaining data integrity.
Data Source
AI summary
A refresh control device may include a command decoder configured to decode a command signal and a specific address, and output a refresh signal, an active signal and a row hammer refresh signal. The refresh control device may include a refresh controller configured to output an active address, a row hammer address and a refresh address based on the refresh signal, the active signal, the row hammer refresh signal and a latch address. The refresh control device may include a combiner configured to combine the active address, the row hammer address and the refresh address, and output a refresh control signal.