Power Semiconductor Junction Temperature Sensing Without Calibration
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Solution Overview
Problem
Existing methods for determining junction temperature in power semiconductors require high time resolution and high-resolution current and voltage measurements, are sensitive to load conditions, and often necessitate complex calibration phases, making them unsuitable for high-frequency applications and prone to inaccuracies due to sensor malfunctions.
Innovation Solution
A method and device using a temperature-sensitive electrical parameter with a compensation module composed of switches and capacitors or resistors to measure junction temperature without requiring high-resolution measurements, compensating for signal source drifts and external circuit variations, allowing determination during normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If TSEP-based methods are used for junction temperature estimation, then temperature can be measured during operation, but high time resolution and high-resolution current measurement are required which are not compatible with product deployment
Solution Approach 1:
The patent extracts the temperature measurement function from the complex existing TSEP-based systems by using a dedicated simple circuit that measures only the necessary voltage parameter across the semiconductor junction, eliminating the need for complex current measurement and high-resolution sampling equipment
Solution Approach 2:
The invention uses a simple, inexpensive measurement circuit that can be implemented with basic electronic components, replacing expensive and complex measurement systems with affordable alternatives that achieve sufficient measurement accuracy without requiring high-resolution current measurement capabilities
2Productivity
If TSEP parameters are measured during power semiconductor operation, then temperature can be monitored in real-time, but complex calibration phases are necessary due to load condition variations
Solution Approach 1:
The measurement circuit automatically compensates for load condition variations and temperature drift without requiring external calibration procedures. The circuit self-adjusts by measuring the voltage across the semiconductor junction directly, which inherently reflects the temperature regardless of operating conditions, eliminating the need for complex calibration phases
3Measurement precision
If implanted sensors are used for junction temperature measurement, then temperature can be measured directly, but sensor malfunction can indicate wrong temperature values
Solution Approach 1:
The patent introduces an intermediary measurement circuit that measures the voltage across the semiconductor junction indirectly through a simple resistive divider network. This intermediary approach provides a backup measurement path that is less susceptible to sensor malfunction, as the measurement is taken through external circuitry rather than relying solely on implanted sensors that could fail
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
Accurately determines junction temperature without needing precise signal sources or high-resolution measurements, compensating for drifts and malfunctions, and reduces implementation complexity by eliminating the need for stable external circuits and measurement modules throughout the semiconductor's lifetime.
Implementation Method 1
using a temperature sensitive electrical parameter of a thermal sensitive electrical device
Data Source
AI summary
The present invention concerns a method for determining the junction temperature of a power semiconductor using a temperature sensitive electrical parameter of a thermal sensitive electrical device in a system comprising the thermal sensitive electrical device, an external electrical circuit, a compensation module and a measurement module. The compensation module is composed at least of a first and a second switches. The invention: —puts the first switch in a closing state and puts the second switch in an opening state during a first period of time in order to measure a first set of voltages, —changes the state of the first switch and/or the state of the second switch or the state of at least one another switch during at least one another period of time in order to measure at least one another voltage, —determines a value of the temperature sensitive parameter using the measured voltages.