In-Vehicle Memory Life Prediction Using Distance-Based Temperature Sensing
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Solution Overview
Problem
The life of nonvolatile memory in in-vehicle camera systems is difficult to accurately predict due to variations in temperature caused by heat generating components on the same substrate, which are influenced by distance and use conditions, leading to unreliable performance and high costs when using NAND flash memory.
Innovation Solution
An in-vehicle electronic device with a processing controller, temperature sensors, and a remaining warranty period calculation unit that switches between first and second determination methods for calculating the remaining warranty period of nonvolatile memory based on temperature coefficients, considering distance and time since activation, to accurately measure temperature and predict memory life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If NAND flash memory is used instead of NOR flash memory, then cost is reduced, but data holding characteristics deteriorate and reliability decreases
Solution Approach 1:
The patent changes the parameter of temperature monitoring by introducing multiple temperature sensors at different locations and using distance-based temperature coefficient selection. This allows accurate temperature prediction for NAND flash memory, enabling reliable life prediction and wear leveling that compensates for NAND's inherently lower data holding characteristics compared to NOR memory
Solution Approach 2:
The patent implements feedback by continuously monitoring temperature through multiple sensors, calculating remaining warranty periods based on accumulated rewriting times and temperature data, and using this information to manage memory cell usage. This feedback mechanism ensures NAND flash memory operates within reliable parameters, mitigating its weaker data holding characteristics
2Device complexity
If temperature is monitored using a single temperature sensor, then device complexity is reduced, but measurement precision deteriorates due to distance variations from heat generating components
Solution Approach 1:
The patent segments the temperature monitoring function by placing multiple temperature sensors at different locations on the substrate. Each sensor monitors its local temperature zone, and the system selects or combines readings based on distance to heat generating components. This segmentation allows accurate temperature measurement across different spatial zones while maintaining manageable device complexity
Solution Approach 2:
The patent applies local quality by having different temperature sensors positioned at specific locations relative to heat generating components. The system selects temperature coefficients and sensor readings based on local conditions (distance to heat sources), ensuring accurate temperature measurement for each specific area of the memory device
3Device complexity
If the remaining warranty period is calculated using a fixed temperature coefficient, then calculation simplicity is improved, but prediction accuracy deteriorates due to varying distances from heat generating components
Solution Approach 1:
The patent makes the temperature coefficient dynamic by selecting different coefficients based on the distance between temperature sensors and heat generating components. Instead of using a fixed coefficient, the system dynamically adjusts the temperature coefficient according to spatial relationships and operational conditions, significantly improving life prediction accuracy for memory cells at different locations
Solution Approach 2:
The patent changes the parameter of temperature coefficient from fixed to variable based on distance measurements. The system calculates or determines appropriate temperature coefficients according to the specific spatial configuration and thermal environment, enabling accurate life prediction that accounts for varying thermal conditions across the memory device
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Accurate temperature measurement and life prediction of nonvolatile memory improve reliability and allow cost-effective use of NAND flash memory, enhancing the in-vehicle electronic device's performance and reducing costs.
Implementation Method 1
a temperature sensor (104, 105, 106)
Data Source
AI summary
Provided is an in-vehicle electronic device including a nonvolatile memory and a heat generating component mounted on one substrate, the in-vehicle electronic device being capable of accurately measuring a temperature of the nonvolatile memory without being affected by a distance from the heat generating component or a use condition. An electronic device mounted on a vehicle includes a processing controller that processes information handled by the electronic device or controls the electronic device, a memory having a plurality of writing areas, a temperature sensor, and a remaining warranty period calculation unit that calculates a remaining warranty period of the memory based on an output from the temperature sensor. The remaining warranty period calculation unit switches between a first determination method for obtaining the remaining warranty period using a first temperature coefficient determined regardless of a distance between the memory and each of a plurality of the temperature sensors and a second determination method for obtaining the remaining warranty period using a second temperature coefficient determined in accordance with the distance between the memory and each of the plurality of the temperature sensors in accordance with a time from activation of the in-vehicle electronic device to obtain the remaining warranty period.