Memory Array Activation Counter Initialization for Aggressor Detection
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Solution Overview
Problem
As memory components decrease in size, the density of memory cells increases, leading to an elevated rate of data degradation in nearby cells due to repeated access, necessitating improved identification and refresh of memory cells at risk.
Innovation Solution
Implementing an activation counter initialization (ACI) mode that initializes access count values for memory cells to a predetermined value, such as 0, to prevent false aggressor alerts and ensure accurate identification of cells requiring refresh.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If access count values are not initialized to a known state, then memory cells can be accessed continuously without reset operations, but false aggressor alerts occur and identification accuracy deteriorates
Solution Approach 1:
The patent applies preliminary action by performing activation counter initialization before normal memory operations begin. The system initializes access count values to a known state (zero) when entering a power state, ensuring that the counters start from a clean baseline. This prevents false aggressor alerts from occurring during subsequent memory access patterns, as the counters accurately reflect only the actual access history rather than containing residual or random values from previous operations.
2Reliability
If access count values start from random or unknown states, then no additional initialization operations are needed, but false aggressor alerts increase and data integrity monitoring fails
Solution Approach 1:
The system performs activation counter initialization as a preliminary action when transitioning into a power state. By resetting the access count values to zero before memory operations resume, the system ensures accurate tracking of actual access patterns. This prevents false aggressor alerts that would otherwise occur due to random or corrupted counter states, thereby maintaining data integrity monitoring effectiveness.
Solution Approach 2:
The patent implements feedback mechanisms where the system monitors access count values and uses this information to identify actual aggressor rows that cause data degradation. The initialization operation resets this feedback loop to a known state, ensuring that subsequent access count measurements accurately reflect current memory access patterns rather than being influenced by previous operations or random states.
3Measurement precision
If activation counter initialization is performed frequently, then identification accuracy is maintained, but operational overhead increases
Solution Approach 1:
The system performs activation counter initialization as a preliminary action only when entering specific power states (such as deep sleep or shutdown states), rather than continuously during normal operation. This selective initialization approach maintains measurement precision by ensuring counters start from a known state before each new access pattern, while avoiding the overhead of frequent re-initialization during active memory operations. The initialization is triggered based on power state transitions, optimizing the balance between accuracy and performance.
Data Source
AI summary
Embodiments of the disclosure are drawn to apparatuses, systems, and methods for activation counter initialization (ACI). A memory may be placed in an ACI mode. During the ACI mode, an ACI control circuit initializes the access count values of the memory array to an initialization value. For example, the ACI mode may work through the array on a row-by-row basis initializing the access count values along each of the rows. By controlling the initial state of the access count values, it is less likely to have a false aggressor alert because none of the access count values start at a randomly high number, simulating an aggressor even after a small number of accesses.