DRAM Refresh Control for Idle Radio Memory Retention

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Solution Overview

Problem

Existing radio devices face challenges in managing memory retention in dynamic random access memory (DRAM) circuits, leading to unnecessary power consumption during idle states due to frequent refreshing of unused memory resources.

Innovation Solution

A controller in the radio device manages memory refresh by disabling the refreshing of unallocated memory resources in idle states, using a memory refresh circuit and a memory allocator to identify and control the refresh process based on the state of the radio modem, allowing for flexible power-saving modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If memory refresh is continuously performed to maintain data in DRAM, then data retention is ensured, but power consumption increases

Engineering Contradiction:
Improvedata retentionVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The memory refresh operation is segmented into two categories: allocated memory resources that require refreshing to maintain data, and unallocated memory resources that can have refreshing disabled. The memory refresh circuit selectively applies refresh operations only to allocated memory blocks, dividing the memory space into active and inactive segments based on allocation status.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of performing full memory refresh on all DRAM resources, the system applies partial refresh action only to the extent necessary - specifically to allocated memory resources that contain active data. This partial action approach refreshes only the minimum required portion of memory, avoiding excessive refresh operations on unallocated memory while still ensuring data retention for active memory regions.

Inventive Principle:
Principle #16Partial or excessive action

2Use of energy by moving object

If memory refresh is disabled for unallocated memory resources, then power consumption is reduced, but data loss may occur in those resources

Engineering Contradiction:
Improvepower consumptionVSAvoiddata retention
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The memory management system implements feedback mechanisms where the memory allocator provides real-time information about memory allocation status to the memory refresh circuit. This feedback loop ensures that the refresh circuit accurately identifies which memory resources are allocated and require refreshing, and which are unallocated and can safely have refresh disabled, preventing data loss in allocated regions while saving power in unallocated regions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The memory refresh system operates autonomously based on allocation information, where the memory refresh circuit automatically adjusts its refresh operations according to the current allocation state without requiring manual intervention. The system self-regulates by monitoring allocation status and dynamically enabling or disabling refresh for different memory regions, ensuring data retention where needed while conserving power where not needed.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4033365B1Memory retention for radio device
Publication Date: 2025.12.03 NORDIC SEMICONDUCTOR
  • EP4033365B1 patent drawingFigure 1~2
  • EP4033365B1 patent drawingFigure 3~4
  • EP4033365B1 patent drawingFigure 5~6

AI summary

This document discloses a solution for controlling refreshing of memory resources of a dynamic random access memory. According to an aspect, there is disclosed an apparatus for a radio device, comprising: a dynamic random access memory circuit; a memory allocator configured to allocate memory resources from the dynamic random access memory circuit and to determine unallocated memory resources; a radio modem configured to communicate with the memory allocator in order to gain memory resources from the dynamic random access memory circuit; a memory refresh circuit configured to refresh the memory resources of the dynamic random access memory circuit; and a controller configured to determine, on the basis of a state change signal received from a radio modem of the radio device, that the radio modem is in an idle state and, in response to said determining, to control the memory refresh circuit to disable said refresh of the unallocated memory resources.