Current-Dependent Thermal Shutdown Threshold Control
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Solution Overview
Problem
Electronic power devices with multiple channels face thermal shutdown issues due to heat dissipation from neighboring channels, leading to premature shutdown even when operating within safe temperature limits, caused by mismatched thermal shutdown thresholds and thermal gradients.
Innovation Solution
A controller adjusts the thermal shutdown threshold based on the current level or estimated power dissipation of each channel, allowing for a dynamic selection between a lower threshold for self-heating protection and a higher threshold to prevent unnecessary shutdowns due to heat from neighboring channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed thermal shutdown threshold is used for all channels, then power stages conducting high current are protected from self-heating damage, but power stages conducting low current experience premature shutdown due to heat from neighboring channels
Solution Approach 1:
The patent implements dynamic thermal shutdown thresholds that automatically adjust based on the operating current of each power stage. The controller monitors the current level and selects between a first threshold (for high current self-heating protection) and a second threshold (for low current operation with reduced sensitivity to neighboring heat), allowing the system to adapt its protection strategy to actual operating conditions and prevent premature shutdown
Solution Approach 2:
The patent applies different thermal shutdown thresholds to different power stages based on their individual current levels. Each channel receives a customized threshold appropriate to its operating conditions rather than a uniform system-wide threshold, enabling localized optimization of thermal protection for each power stage independently
2Temperature
If a low thermal shutdown threshold is used, then power stages are protected from overheating, but shutdown occurs even when temperature rise is due to neighboring channels and not self-heating
Solution Approach 1:
The controller dynamically switches between a first thermal shutdown threshold and a second thermal shutdown threshold based on the measured current level. When current exceeds a reference level, the first (lower) threshold applies for strict thermal protection. When current is below the reference level, the second (higher) threshold applies to prevent unnecessary shutdown from ambient heat, thus adapting the temperature protection level to actual operating conditions
3Productivity
If a high thermal shutdown threshold is used, then premature shutdown due to neighboring heat is prevented, but power stages conducting high current may exceed safe temperature limits
Solution Approach 1:
The system employs a current-dependent threshold selection mechanism where the controller compares the actual current against a reference current level. For high current operation (above reference), a first lower threshold ensures safe temperature limits are not exceeded. For low current operation (below reference), a second higher threshold allows continuous operation by being less sensitive to thermal gradients from neighboring channels, thus maintaining productivity while ensuring safety
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 effectively reduces the likelihood of premature shutdowns in electronic power devices by dynamically adjusting thermal shutdown thresholds, ensuring reliable operation even when subjected to thermal gradients from neighboring channels.
Implementation Method 1
the controller is configured to receive a measurement of a current through the first pass element. Based on the measurement of the current, the controller is further configured to select a thermal shutdown threshold.
Implementation Method 2
a first temperature sensor on the substrate arranged to output a measurement of the first temperature to the controller
Data Source
AI summary
According to an example, a device comprises a pass element and a controller. The controller is configured to receive a measurement of a current through the pass element. Based on the measurement of the current, the controller is configured to select a thermal shutdown threshold. The controller is further configured to turn off the pass element based on a determination that a temperature of the pass element is greater than the thermal shutdown threshold.