Parallel IGBT MOSFET Lead Frame Thermal Isolation
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Solution Overview
Problem
Conventional semiconductor modules face thermal interference issues between IGBTs and MOSFETs, leading to thermal damage, as they are often connected in a configuration where one component's heat influences the other, affecting performance and reliability.
Innovation Solution
The semiconductor module design includes IGBTs and MOSFETs connected in parallel on the same lead frame, with one switching element disposed at a position separated from the conduction path of the other, ensuring minimal thermal influence between them, and a cooling system that prioritizes the first-driven IGBT for efficient heat management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If IGBT and MOSFET are connected in parallel on the same lead frame, then both excellent characteristics of IGBT and MOSFET are achieved, but thermal interference occurs between the two switching elements
Solution Approach 1:
The lead frame is divided into separate conduction paths for IGBT and MOSFET, with the MOSFET conduction path positioned away from the IGBT conduction path. This spatial segmentation prevents heat generated in the IGBT conduction path from affecting the MOSFET, while still allowing both devices to function on the same lead frame structure.
Solution Approach 2:
Different regions of the lead frame are designed with different thermal management characteristics. The MOSFET is positioned in a region separated from the IGBT conduction path, creating a local thermal environment that is protected from IGBT heat generation. This allows each switching element to operate in its optimal thermal zone.
2Area of stationary object
If MOSFET is positioned under the IGBT conduction path, then compact design is achieved, but MOSFET receives thermal influence from IGBT heat
Solution Approach 1:
Instead of positioning the MOSFET directly under the IGBT in the vertical dimension, the design shifts the MOSFET to a laterally separated position on the same lead frame plane. This dimensional repositioning maintains compact overall layout while eliminating direct thermal coupling between the IGBT conduction path and MOSFET.
3Ease of manufacture
If bus bar is placed directly under MOSFET for current flow, then electrical connection is simplified, but MOSFET receives thermal influence from bus bar in high temperature state
Solution Approach 1:
The MOSFET is extracted from the area directly under the IGBT conduction path and bus bar, positioning it in a separate region of the lead frame. This extraction removes the MOSFET from the high-temperature zone created by IGBT operation and bus bar heating, while electrical connections are maintained through the lead frame's conductive structure.
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 configuration effectively suppresses mutual thermal influence between IGBTs and MOSFETs, enhancing their performance and allowing for reduced element sizes, improved cooling efficiency, and better fuel economy by optimizing switching and conduction losses.
Implementation Method 1
a cooling plate... provided on the same lead frame... the first switching element is less likely to be thermally influenced by heat generated in the conduction path
Data Source
AI summary
A semiconductor module of an electric power converter includes an IGBT and a MOSFET which are connected in parallel to each other and provided on the same lead frame, either one of the IGBT and the MOSFET is a first switching element and the remaining one is a second switching element, and the conduction path of the second switching element is disposed at a position that is separated from a conduction path of the first switching element in the same lead frame.