Switching Element Temperature Sensing via Turn-Off Miller Voltage
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Solution Overview
Problem
Existing semiconductor devices face challenges in accurately measuring chip temperature due to unstable turn-on gate-voltage and increased complexity in structure and manufacturing process, particularly when trying to detect temperature without increasing the number of control terminals in a package.
Innovation Solution
A semiconductor device incorporating a switching element with a control electrode, gate driver, Miller voltage detector, current value detector, and temperature calculator that calculates chip temperature from detected Miller voltage and principal current, allowing for accurate temperature measurement without additional control terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a temperature detecting element such as a diode is arranged on a semiconductor chip, then temperature detection capability is achieved, but the structure and manufacturing process become complicated and the number of control terminals of a package is increased
Solution Approach 1:
The invention extracts the temperature detection function from a separate temperature detecting element and integrates it into the gate driver circuit by utilizing the Miller voltage that naturally occurs during switching element operation. This eliminates the need for independent temperature detecting elements and additional control terminals while maintaining temperature detection capability.
Solution Approach 2:
The gate driver circuit is given multiple functions: it not only drives the switching element but also detects temperature through Miller voltage measurement. This multi-functionality approach allows temperature detection without adding separate dedicated temperature detection components or control terminals.
2Reliability
If turn-on gate-voltage is used to obtain element temperature, then temperature measurement is achieved, but the measurement accuracy is poor due to instability of turn-on gate-voltage
Solution Approach 1:
Instead of using turn-on gate-voltage for temperature measurement, the invention inverts the approach by using turn-off Miller voltage. The Miller voltage that occurs during turn-off is more stable and provides better measurement accuracy for temperature determination.
3Reliability
If only first voltage having certain relation with voltage applied to IGBT is used to calculate temperature, then temperature calculation is achieved, but the temperature measurement accuracy is insufficient
Solution Approach 1:
The invention changes the measured parameter from simple voltage to Miller voltage which has a more direct and stable relationship with temperature. By measuring Miller voltage at a specific timing during turn-off and combining it with current information, the temperature calculation accuracy is significantly improved.
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 accurate chip temperature measurement with a simple structure, reducing the complexity of the package and avoiding the need for additional control terminals, thereby improving temperature detection reliability.
Implementation Method 1
a Miller voltage detector detecting a Miller voltage between the control electrode and the first main electrode when the switching element turns off
Data Source
AI summary
A semiconductor device includes a switching element including a control electrode, a first main electrode, and a second main electrode: a gate driver connected between the control electrode and the first main electrode, configured to transmit a gate drive signal for driving the control electrode; a Miller voltage detector detecting a Miller voltage between the control electrode and the first main electrode when the switching element turns off; a current value detector detecting a principal current flowing through the switching element; and a temperature calculator calculating a temperature of the switching element from the detected Miller voltage and principal current.