Lateral High Voltage Transistor Package for EMI Reduction
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Solution Overview
Problem
High voltage switching circuits face issues with capacitance between the drain of transistors and circuit or DC ground, leading to increased electromagnetic interference (EMI) and switching losses, which degrade performance and heat dissipation, creating a trade-off between electrical performance and heat dissipation.
Innovation Solution
Packaged lateral high voltage transistors with an insulating or semi-insulating portion and a semiconductor body, where the source, gate, and drain electrodes are on the same side, and a shim or substrate is used to prevent electrical contact with the ground, reducing capacitance and improving heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a thin insulating spacer is used between the package base and heat sink, then heat dissipation is improved, but capacitance between drain and ground increases leading to higher EMI and switching losses
Solution Approach 1:
The package structure is segmented into distinct functional zones: the package base for electrical connections, the insulating spacer for thermal management, and the heat sink for heat dissipation. This segmentation allows each component to be optimized independently - the insulating spacer can be made thin for heat dissipation while the package base configuration minimizes capacitance effects
Solution Approach 2:
The insulating spacer acts as an intermediary element between the package base and heat sink. It provides the necessary electrical isolation while enabling thermal conduction, mediating between the conflicting requirements of electrical performance and thermal management
2Object-affected harmful factors
If a thick insulating spacer is used between the package base and heat sink, then capacitance between drain and ground is reduced improving electrical performance, but heat dissipation capability deteriorates
Solution Approach 1:
The thickness of the insulating spacer is optimized to a specific parameter range that balances electrical and thermal requirements. By changing this physical parameter to an optimal value, the system achieves both low capacitance and adequate heat dissipation simultaneously
3Temperature
If the package base and heat sink are electrically connected, then heat dissipation is maximized, but capacitance between drain and ground increases causing common-mode AC currents
Solution Approach 1:
The insulating spacer serves as an intermediary that breaks the direct electrical connection between the package base and heat sink while maintaining thermal contact. This eliminates the capacitive coupling path for common-mode currents while preserving the thermal conduction path for heat dissipation
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 reduces EMI and switching losses, enhances heat dissipation, and improves the operational efficiency and longevity of high voltage switching circuits, allowing for wider application use.
Implementation Method 1
The transistor is mounted directly to the package with the insulating or semi-insulating portion contacting the package base
Implementation Method 2
the heat generated during operation can easily dissipate to the package base
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
An electronic component includes a high voltage switching transistor encased in a package. The high voltage switching transistor comprises a source electrode, a gate electrode, and a drain electrode all on a first side of the high voltage switching transistor. The source electrode is electrically connected to a conducting structural portion of the package. Assemblies using the abovementioned transistor with another transistor can be formed, where the source of one transistor can be electrically connected to a conducting structural portion of a package containing the transistor and a drain of the second transistor is electrically connected to the second conductive structural portion of a package that houses the second transistor. Alternatively, the source of the second transistor is electrically isolated from its conductive structural portion, and the drain of the second transistor is electrically isolated from its conductive structural portion.