Nonvolatile Memory Temperature Monitoring via Retention Error Rates

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Solution Overview

Problem

Current methods for monitoring temperature exposure in nonvolatile memory systems are limited in their ability to accurately determine temperature exposure without power and effectively manage data retention, especially for bi-stable memory cells where temperature-dependent data retention error rates are difficult to measure.

Innovation Solution

A temperature exposure detection system utilizing nonvolatile memory cells with read circuitry and determination circuitry that determines data retention error rates to correlate with temperature exposure profiles, allowing for monitoring without power and using bi-stable memory cells like MRAM to simplify the process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If temperature measurement mechanisms are used to monitor temperature exposure, then temperature monitoring capability is improved, but device complexity and power consumption increase

Engineering Contradiction:
Improvetemperature monitoring capabilityVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The memory cells themselves serve as temperature sensors by exploiting their inherent temperature-dependent data retention characteristics. The system monitors temperature exposure through read error rates without requiring external temperature measurement mechanisms, thus achieving temperature monitoring while minimizing additional device complexity and power consumption

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The memory cells perform dual functions: data storage and temperature monitoring. By utilizing the same memory cells for both purposes and exploiting their natural temperature-dependent behavior, the system eliminates the need for separate temperature sensing components, reducing overall device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If data scanning is performed regularly to monitor data health, then data retention management is improved, but loss of time and productivity decrease

Engineering Contradiction:
Improvedata retention managementVSAvoidloss of time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system implements periodic background data scanning at optimized intervals to detect temperature-induced data retention degradation. By performing scans at strategically determined intervals rather than continuously, the system maintains reliable data monitoring while minimizing time loss and maximizing productivity

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system uses read error rates as feedback indicators of temperature exposure and data retention health. When error rates exceed thresholds, the system triggers data refreshing or corrective actions, enabling proactive data retention management without requiring continuous monitoring, thus reducing time loss

Inventive Principle:
Principle #23Feedback

3Measurement precision

If multiple cell groups with different temperature dependent profiles are used, then temperature exposure detection accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvetemperature exposure detection accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The memory array is divided into multiple cell groups, where each group contains memory cells with different temperature-dependent data retention characteristics. By segmenting the memory into groups with varying thermal stability profiles, the system can detect a broader range of temperature exposures with higher accuracy, as different cell groups respond differently to various temperature levels

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different cell groups are designed with specific local qualities in terms of their temperature dependence profiles. Each cell group is optimized to detect particular temperature ranges or characteristics, allowing the system to achieve high temperature detection accuracy across different operating conditions by selecting or combining results from appropriate cell groups

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4137791B1Temperature exposure detection based on memory cell retention error rate
Publication Date: 2024.09.18 NXP BV
  • EP4137791B1 patent drawingFigure 1
  • EP4137791B1 patent drawingFigure 2
  • EP4137791B1 patent drawingFigure 3

AI summary

A temperature exposure detection system includes a plurality of nonvolatile memory cells. The memory includes memory read circuity for reading the plurality of memory cells to determine a data retention error rate of the plurality of memory cells. The temperature exposure detection system determines a temperature exposure of the system based on the determined data retention error rate.