Adaptive Memory Refresh Rate Control for Error Management

Solution Overview

Problem

Memory errors in control systems, particularly in automation systems like automotive vehicles, pose challenges due to the tradeoff between refresh rate, power consumption, and availability, affecting operational reliability and efficiency, especially under varying environmental conditions.

Innovation Solution

The control system adaptively adjusts the refresh rate of memory devices like DRAM based on expected memory error correctability, increasing the refresh rate when errors are not correctable and maintaining or reducing it when errors are expected to be correctable, to balance memory errors, power consumption, and availability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the refresh rate of the memory device is increased to reduce memory errors, then reliability is improved, but power consumption increases

Engineering Contradiction:

Improvememory error reductionVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic refresh rate adjustment where the memory refresh rate is not fixed but adapts based on real-time error metrics. The system monitors memory error rates and adjusts the refresh rate dynamically - increasing it when errors are detected and decreasing it when the memory is stable, thereby resolving the contradiction between maintaining high reliability and reducing power consumption.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameter (refresh rate) of the memory device based on measured error metrics. By monitoring bit flip rates and other error indicators, the system adjusts the refresh rate parameter to optimize the balance between error correction and power consumption, rather than operating at a constant high refresh rate.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the refresh rate of the memory device is increased to reduce memory errors, then reliability is improved, but memory device availability decreases

Engineering Contradiction:

Improvememory error reductionVSAvoidmemory device availability

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent implements dynamic refresh rate adjustment where the memory refresh rate is not fixed but adapts based on real-time error metrics. The system monitors memory error rates and adjusts the refresh rate dynamically - increasing it when errors are detected and decreasing it when the memory is stable, thereby resolving the contradiction between maintaining high reliability and reducing power consumption.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameter (refresh rate) of the memory device based on measured error metrics. By monitoring bit flip rates and other error indicators, the system adjusts the refresh rate parameter to optimize the balance between error correction and power consumption, rather than operating at a constant high refresh rate.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If adaptive refresh rate adjustment is implemented based on error metrics, then operational reliability is improved, but system complexity increases

Engineering Contradiction:

Improveoperational reliabilityVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where memory error metrics (such as bit flip rates) are continuously monitored and fed back to the memory controller. This feedback loop enables the system to automatically adjust the refresh rate based on actual memory conditions, improving reliability while keeping the complexity manageable through automated closed-loop control rather than complex manual management.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The memory system performs self-diagnosis and self-adjustment by monitoring its own error metrics and automatically modifying its refresh rate. This self-service capability reduces the need for external intervention or complex control systems, as the memory subsystem manages its own reliability optimization autonomously based on its operational state.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS11481126B2Memory device error based adaptive refresh rate systems and methods

Publication Date: 2022.10.25 MICRON TECHNOLOGY INC

AI summary

One embodiment describes an automation system including a sensor that determines operational parameters of the automation system; one or more actuators that perform control actions during operation of the automation system; and a control system communicatively coupled to the sensor and the one or more actuators. The control system includes memory that stores the operational parameters; determines occurrence of memory errors in data stored in the memory; determines error parameters that indicate characteristics of the memory errors; determines error-corrected data by correcting the memory errors based at least in part on the error parameters; adaptively adjusts a refresh rate used to refresh stored data in the memory based at least in part on the error parameters; and determines control commands instructing the one or more actuators to perform the control actions by processing the error-corrected data.