Junction Temperature Estimation via Emulator Circuit
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Solution Overview
Problem
Existing methods for monitoring junction temperatures in power semiconductor devices are limited by the need for external sensors, high complexity, and inability to monitor multiple temperatures without increasing circuit complexity and calibration effort.
Innovation Solution
A method that estimates junction temperatures using an emulator circuit with tunable resistance and capacitance, allowing for dynamic adaptation of temperature estimation range and sensitivity, and eliminating the need for external ADCs by using a Time-to-Digital Converter or FPGA for signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple temperature values are monitored by duplicating the monitoring circuit, then the measurement capability is improved, but the device complexity and calibration effort are worsened
Solution Approach 1:
The patent implements a universal OTD circuit that can monitor multiple temperature values by dynamically reconfiguring its operation. Instead of duplicating hardware circuits for each temperature threshold, a single OTD circuit is designed to be programmable and adaptable, allowing it to serve multiple temperature monitoring functions through software control and parameter adjustment.
Solution Approach 2:
The OTD circuit incorporates dynamic reconfiguration capabilities where the temperature threshold and monitoring parameters can be changed during operation. The circuit transitions from static to dynamic operation, allowing the same hardware to adapt to different temperature monitoring requirements without physical reconfiguration or duplication.
2Measurement precision
If the TSEP characteristics are unique for each device requiring individual calibration, then the measurement precision is improved, but the manufacturing complexity is worsened
Solution Approach 1:
The patent implements self-calibration functionality where the OTD circuit automatically adjusts its parameters based on device-specific TSEP characteristics. The calibration process is performed autonomously without requiring manual intervention for each device, reducing the calibration effort while maintaining measurement precision through automated adaptation to individual device properties.
Solution Approach 2:
The system dynamically adjusts calibration parameters based on measured TSEP characteristics of each device. By changing operational parameters automatically rather than requiring fixed manual calibration, the system achieves device-specific precision while simplifying the manufacturing process.
3Measurement precision
If the OTD circuit is made specific for each monitored device, then the measurement accuracy is improved, but the adaptability is worsened
Solution Approach 1:
The OTD circuit is designed as a universal platform that can be configured for different devices through software programming rather than hardware customization. The same physical circuit can adapt to monitor different temperature thresholds and characteristics of various power transistors, achieving device-specific accuracy without sacrificing reconfigurability.
4Ease of operation
If the time-to-temperature sensitivity is low, then the measurement simplicity is improved, but the measurement precision is worsened
Solution Approach 1:
The system dynamically adjusts measurement parameters such as time intervals, sampling rates, and threshold values to optimize the time-to-temperature sensitivity. By changing operational parameters rather than requiring complex hardware modifications, the system maintains measurement simplicity while improving precision through adaptive parameter optimization.
Data Source
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AI summary
A measurement method for estimating junction temperatures of a power semi-conductor module comprising: a. duplicating a pulse current; b. injecting simultaneously - a first duplicated pulse current to a control electrode of a power transistor of said power semi-conductor module, and - a second duplicated pulse current to an emulator circuit comprising a resistance in series with a capacitor; c. comparing a voltage signal of said power transistor and a voltage signal of said emulator circuit in such a way to generate a comparison signal; d. in function of said comparison signal, measuring duration (Δt) of said voltage signal of said power transistor to reach the same value as said voltage signal of said emulator circuit; e. converting said measured duration (Δt) into an estimated value of a junction temperature (TJ).