Refresh Control Device Using Dual Oscillators to Mitigate Row Hammering
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Solution Overview
Problem
The increasing integration density of memory devices leads to a coupling effect between word lines, causing data disturbance and row hammering, where frequently activated word lines damage adjacent memory cell data, resulting in refresh failures.
Innovation Solution
A refresh control device utilizing multiple oscillators with different cycles to generate oscillation signals, which are used to latch and output addresses randomly, thereby reducing refresh failures by preventing concentration of accesses on specific addresses during refresh operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple oscillators with different cycles are used to generate row hammer addresses, then refresh reliability is improved by reducing row hammering, but device complexity increases
Solution Approach 1:
The refresh control device is segmented into multiple independent oscillators (first oscillator, second oscillator, etc.), each generating oscillation signals with different cycles. This segmentation allows the system to produce diverse row hammer addresses through different oscillation patterns, thereby improving refresh reliability by reducing row hammering effects while maintaining manageable complexity through modular design.
2Reliability
If addresses are randomly synchronized using multiple oscillators, then row hammering is mitigated, but control complexity increases
Solution Approach 1:
Multiple oscillators generate periodic oscillation signals with different cycles to control the latching and selection of row hammer addresses. The first address controller latches addresses based on the first oscillation signal, while the second address controller latches addresses based on the second oscillation signal. This periodic action with varying cycles ensures random synchronization of addresses, effectively mitigating row hammering while maintaining systematic control through the selector that chooses between different address controllers based on refresh signals.
Data Source
AI summary
A refresh control device may include a first oscillator configured to generate a first oscillation signal, a second oscillator configured to generate a second oscillation signal having a different cycle from the first oscillation signal, a first address controller configured to latch an address in response to the first oscillation signal, and output the latched address when a refresh signal is enabled. The refresh control device may also include a second address controller configured to latch the address in response to the second oscillation signal, and output the latched address when the refresh signal is enabled. Further included may be a selector configured to select any one of the output of the first address controller and the output of the second address controller in response to a select signal, and output the selected output as a row hammer address.