Semiconductor Temperature Sensor Redundancy for ASIL D Compliance
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Solution Overview
Problem
Semiconductor devices in in-vehicle electronic systems face challenges in accurately measuring temperature across different locations, especially within the guaranteed operation range of -40°C to 125°C, due to varying heat distribution and the need for functional safety compliance with ISO 26262 ASIL D standards.
Innovation Solution
The semiconductor device employs multiple temperature sensor modules with bandgap reference circuits and analog-to-digital conversion circuits to generate and compare temperature values, ensuring accurate temperature measurement by determining the difference between temperatures measured by each module, thereby confirming correct operation within the specified range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple temperature sensor modules are mounted on the semiconductor device to monitor temperature at different locations, then temperature monitoring coverage is improved, but it becomes impossible to verify whether the temperature can be correctly measured across the full operational range from -40°C to 125°C because each sensor measures different local temperatures
Solution Approach 1:
The temperature sensor module is segmented into multiple independent measurement paths, each with its own temperature sensor and ADC circuit. This allows each path to be independently tested and verified, resolving the contradiction by enabling comprehensive temperature range verification while maintaining multiple measurement points for reliable monitoring
Solution Approach 2:
Multiple temperature sensor modules are implemented as identical copies with the same measurement functionality. Each module independently measures temperature and generates digital values, allowing verification through comparison of equivalent measurements across different locations while maintaining the ability to test the full temperature range
2Measurement precision
If temperature is measured only at the current moment in normal use environments, then the measurement system remains simple, but it is not possible to test whether the temperature can be correctly measured across the full temperature range from -40°C to 125°C
Solution Approach 1:
Temperature verification testing is performed preliminarily during the manufacturing process before the semiconductor device is deployed. This preliminary action ensures that temperature measurement accuracy across the full -40°C to 125°C range is verified in advance, eliminating the need for extended field testing while maintaining measurement precision
Solution Approach 2:
The temperature sensor module performs self-verification by comparing its own temperature measurements with reference values or with other identical sensor modules during manufacturing testing. This self-service capability enables comprehensive temperature range verification without requiring external testing equipment or extended time
3Reliability
If a single temperature sensor module is used to measure temperature, then the device structure remains simple, but it cannot provide redundant verification for functional safety compliance with ISO 26262 ASIL D standards
Solution Approach 1:
Temperature sensor modules are strategically placed at different locations within the semiconductor device where temperature conditions may vary. Each location has its own sensor providing localized temperature monitoring, enabling functional safety verification through comparison of readings from different thermal zones while maintaining necessary redundancy for ASIL D compliance
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
This solution allows for reliable temperature measurement across the semiconductor device, ensuring functional safety compliance and accurate temperature monitoring within the operational range, even with varying heat distribution, by using multiple temperature sensor modules to verify and compare temperature readings.
Implementation Method 1
a bandgap reference circuit that generates a reference voltage
Data Source
AI summary
A semiconductor device includes a first temperature sensor module, a second temperature sensor module, a first temperature controller, and a second temperature controller. The first temperature sensor module includes a bandgap reference circuit that outputs a plurality of divided voltages, and a first conversion circuit that performs analog-to-digital conversion processing on one of the plurality of divided voltages to generate a first digital value. The second temperature sensor module includes a second conversion circuit that performs analog-to-digital conversion processing on the one of the plurality of divided voltages to generate a second digital value. The first temperature sensor controller converts the first digital value to a first temperature. The second temperature sensor controller converts the second digital value to a second temperature. The semiconductor device determines whether the first and second temperature modules operate normally based on a difference between the first temperature and the second temperature.