Refresh Control Circuit for DDR5 Row Hammer Supplementary Refresh

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Solution Overview

Problem

Frequent switching of refresh modes in DDR5 SDRAM leads to vulnerabilities in row hammer protection, necessitating a robust control strategy to maintain stability.

Innovation Solution

A refresh control circuit that includes a count flag circuit, count processing circuit, and first control circuit to generate a supplementary refresh indication signal based on counting results, ensuring row hammer protection across varying refresh modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If frequent switching of refresh modes is performed to adapt to different memory access patterns, then adaptability is improved, but row hammer protection reliability deteriorates

Engineering Contradiction:

Improverefresh mode adaptabilityVSAvoidrow hammer protection

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent performs supplementary refresh operations in advance based on predicted access patterns. The refresh control circuit proactively identifies victim rows that are likely to be accessed frequently and performs refresh operations on adjacent rows before the row hammer attack can occur, rather than waiting for the attack to be detected

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where the refresh control circuit monitors memory access patterns and refresh operation results, then adjusts the supplementary refresh strategy accordingly. The circuit uses the counting result of refresh operations to determine when to trigger supplementary refresh, creating a closed-loop control system that adapts to actual memory usage while maintaining protection

Inventive Principle:

Principle #23Feedback

2Reliability

If supplementary refresh operations are performed frequently to ensure row hammer protection, then row hammer protection reliability is improved, but energy consumption increases

Engineering Contradiction:

Improverow hammer protectionVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies refresh operations locally only to specific victim rows and their adjacent rows that are identified as needing protection, rather than performing full bank refresh operations. The refresh control circuit determines specific target rows based on access patterns and confines refresh operations to those localized regions, reducing overall energy consumption

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent dynamically changes the refresh operation parameters based on the counting result. When the count of refresh operations reaches a preset threshold, the circuit triggers supplementary refresh with adjusted timing and scope parameters, optimizing the balance between protection reliability and energy consumption by adapting parameters to actual usage conditions

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the refresh control circuit monitors and counts refresh operations to trigger supplementary refresh, then row hammer protection is improved, but device complexity increases

Engineering Contradiction:

Improverow hammer protectionVSAvoidcontrol circuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The refresh control circuit performs multiple functions using the same hardware resources. The counting circuit not only counts refresh operations to determine when supplementary refresh is needed, but also tracks access patterns and coordinates with the refresh command generation logic. This multi-functionality reduces the need for separate dedicated circuits for each function

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The refresh control circuit uses its own internal counting mechanism and logic to autonomously determine when supplementary refresh operations are needed, without requiring external control signals or complex external coordination. The circuit self-manages the monitoring, counting, and triggering of protective refresh operations, reducing overall system complexity

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS20260080930A1Refresh control circuit and memory

Publication Date: 2026.03.19 RUILI INTEGRATED CIRCUIT CO LTD

AI summary

A refresh control circuit includes: a count flag circuit configured to generate and output a count flag signal at an active level based on a refresh activation signal when an all-bank refresh flag signal and a same-bank refresh flag signal are active; a count processing circuit configured to receive the count flag signal and count based on the count flag signal to generate a counting result; and a first control circuit configured to receive the counting result and generate and output, when the counting result is within a first preset range, a supplementary refresh indication signal at an active level. The supplementary refresh indication signal, when active, indicates that an associated memory performs a supplementary refresh operation.