Power Module Die Junction Temperature Sensing via Gate Voltage
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Solution Overview
Problem
The junction temperature of semiconductor power modules cannot be directly measured due to its theoretical average nature and the encapsulation of power semiconductor modules, making traditional temperature sensing methods ineffective, and existing methods rely on indirect inference from thermally sensitive parameters.
Innovation Solution
A method and device that set the die in a non-conducting state and apply a current-limited voltage to the gate during a switching cycle to measure the voltage, allowing derivation of the junction temperature without intrusive means, enabling reliable determination of the junction temperature for health and loading state assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional temperature sensing methods are used, then direct temperature measurement is achieved, but measurement is impossible due to encapsulation and theoretical average nature of junction temperature
Solution Approach 1:
The patent uses an intermediary substance (thermally sensitive parameter) that can be measured indirectly to infer the junction temperature. Instead of directly measuring the temperature at the junction point, the method measures a thermally sensitive parameter that varies with temperature, serving as a mediator between the measurement system and the target temperature.
Solution Approach 2:
The patent replaces traditional mechanical/physical temperature sensing methods with an electrical measurement approach. By measuring electrical parameters (voltage, current) that are thermally sensitive, the system substitutes direct thermal measurement with indirect electrical characterization, enabling temperature determination through electrical means rather than physical contact.
2Measurement precision
If indirect inference from thermally sensitive parameters is used, then junction temperature can be determined, but measurement reliability is reduced compared to direct measurement
Solution Approach 1:
The patent implements a feedback mechanism where the measured thermally sensitive parameter is continuously monitored and used to determine junction temperature. The system establishes a relationship between the measured parameter and temperature, using this feedback loop to reliably infer temperature conditions based on electrical measurements taken during device operation.
Solution Approach 2:
The patent exploits parameter changes in thermally sensitive characteristics that occur with temperature variation. By monitoring how these electrical parameters change with temperature, the system can determine junction temperature through observed parameter variations, transforming temperature measurement into an electrical parameter analysis problem.
3Measurement precision
If intrusive measurement means are used, then direct junction temperature measurement is achieved, but device operation is disrupted and hardware complexity increases
Solution Approach 1:
The patent enables the device to measure its own junction temperature using its existing operational parameters and built-in measurement capabilities. By utilizing thermally sensitive parameters that are already present during normal device operation, the system achieves self-diagnosis functionality without requiring external intrusive measurement equipment, thereby maintaining operational continuity and minimizing additional hardware complexity.
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 non-invasive, reliable measurement of junction temperature, allowing for real-time monitoring of the state of health and loading of semiconductor power modules, reducing hardware costs and sampling time while maintaining operational performance.
Implementation Method 1
measuring the voltage at the gate of the die; deriving from the measured voltage a temperature variation of the junction of the at least one die or the temperature of the junction of the die
Data Source
AI summary
A method for determining the junction temperature of at least one die of a semiconductor power module, the semiconductor power module being composed of plural dies connected in parallel and switching between conducting and non conductor states according to pattern cycles, the method comprises the steps of: disabling the conducting of the at least one die during at least a fraction of one switching cycle, applying a current limited voltage to the gate of the at least one die during a period of time of the cycle wherein the at least one die is not conducting, the resulting voltage excursion having a value that does not enable the die to be conducting, measuring the voltage at the gate of the die, deriving from the measured voltage a temperature variation of the junction of the at least one die or the temperature of the junction of the die.