Over-temperature Detector Test Mode for Accuracy Evaluation
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Solution Overview
Problem
Conventional over-temperature detectors face challenges in accurately determining the actual temperature threshold at which they indicate an over-temperature condition, as testing devices cannot generate the necessary high temperatures, and existing test modes only confirm the detector's ability to trigger an over-temperature warning without evaluating accuracy or ensuring accurate operation at designed conditions.
Innovation Solution
An over-temperature detector with a test output that provides an analog voltage indicative of the difference between the test temperature and the actual threshold temperature, allowing for accurate evaluation of the detector's accuracy without exposing it to high ambient temperatures, and ensuring continued accurate operation even if inadvertently left in test mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional testing devices are used to test the over-temperature detector, then the testing process can be performed, but the devices cannot generate the high temperatures necessary to trigger over-temperature detection
Solution Approach 1:
The patent introduces a test mode that changes the operating parameters of the over-temperature detector to trigger the detection function at a lower temperature than the actual threshold. This allows conventional testing devices to operate within their capability range while still validating the detector's functionality. The test mode effectively scales down the temperature parameter to match available testing equipment capabilities.
2Ease of operation
If the over-temperature detector is placed in test mode to enable testing at reduced temperatures, then testing can be performed, but the accuracy of the detector cannot be evaluated
Solution Approach 1:
The patent incorporates a feedback mechanism that provides information about the actual temperature threshold to the testing system. This feedback allows the testing device to correlate the reduced test temperature with the actual operating threshold, enabling accuracy evaluation. The feedback loop connects the test mode operation back to the actual threshold parameter, making accuracy assessment possible despite operating at reduced temperatures.
3Adaptability or versatility
If the detector is left in test mode after testing, then the testing configuration is maintained, but the detector may report false over-temperature conditions at the reduced temperature
Solution Approach 1:
The patent implements a dynamic test mode that can be selectively activated and deactivated. The test mode is not a permanent state but a temporary operational configuration that can be switched on for testing and switched off for normal operation. This dynamic switching mechanism prevents false indications by ensuring the test mode parameters are only active when explicitly required for testing purposes.
4Productivity
If the actual temperature threshold is not accurately determined, then the detector can operate, but the accuracy of the over-temperature indication cannot be confirmed
Solution Approach 1:
The patent enables preliminary determination of the actual temperature threshold through the test mode before the detector is deployed or before final calibration. By performing measurements and calculations in advance using the test mode, the actual threshold can be accurately established beforehand. This preliminary action ensures accuracy is confirmed prior to normal operation without requiring extreme temperature exposure during final validation.
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
Enables precise evaluation of the detector's accuracy and ensures reliable over-temperature indication at designed conditions, maintaining operational integrity even if the test mode is inadvertently left active.
Implementation Method 1
monitoring variations in the base-emitter voltages (VBE) of combinations of bipolar transistors, where VBE is temperature- and bias current-dependent
Data Source
AI summary
A device for over-temperature detection having a test mode is presented. The device includes a temperature detection circuit having first and second transistors. The temperature detection circuit is configured so that when an ambient temperature of the temperature detection circuit is less than a temperature threshold, a voltage at an emitter terminal of the second transistor is less than a voltage at an emitter terminal of the first transistor minus VT*ln(N), and when the ambient temperature of the temperature detection circuit is greater than the temperature threshold, the voltage at the emitter terminal of the second transistor is greater than a voltage at the emitter terminal of the first transistor minus VT*ln(N). The device includes a measurement circuit configured to generate an output voltage that is proportional to a difference between the temperature threshold of the temperature detection circuit and the ambient temperature of the temperature detection circuit.