Electronic Module Thermal Via Isolation for EMI Reduction
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Solution Overview
Problem
Electronic modules face challenges in reducing electromagnetic interference radiation due to thermal plated-through holes acting as capacitive pathways, which can hinder effective heat dissipation and are not inherently insulated from the outer conductive layers.
Innovation Solution
The electronic module incorporates a multilayer printed circuit board with electrically conductive outer and inner layers, where thermal plated-through holes are isolated from the outer layer, and some are connected to a reference potential, reducing capacitive transmission of high-frequency oscillations and optimizing heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal plated-through holes are provided to conduct heat from the electronic component to the heat sink, then heat dissipation is improved, but electromagnetic radiation is generated through parasitic capacitance
Solution Approach 1:
An electrical insulation layer is introduced as an intermediary between the thermal plated-through holes and the outer conductive layer. This insulation layer blocks the parasitic capacitance coupling while maintaining thermal conduction through the plated-through holes, thus eliminating electromagnetic radiation without compromising heat dissipation
Solution Approach 2:
The plated-through holes are segmented into two functional groups: thermal conduction holes that extend through the insulation layer to the heat sink, and electrical isolation holes that are covered by the outer conductive layer to prevent capacitance coupling. This segmentation allows simultaneous optimization of thermal and electrical performance
2Temperature
If the electrical insulation layer is made thin to reduce thermal resistance, then heat conduction is improved, but parasitic capacitance increases causing more electromagnetic radiation
Solution Approach 1:
The plated-through holes are divided into thermal conduction holes that penetrate the thin insulation layer for heat transfer, and electrical isolation holes that are covered by the outer conductive layer to block capacitance coupling. This segmentation allows the insulation layer to be thin for thermal performance while preventing electromagnetic radiation
Solution Approach 2:
The outer conductive layer acts as an intermediary shielding layer that covers the plated-through holes to block parasitic capacitance coupling to external electromagnetic fields, while the thin insulation layer maintains thermal conduction performance
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 reduces electromagnetic interference radiation and enhances heat dissipation by isolating thermal plated-through holes from the outer layer and connecting them to a reference potential, improving the thermal resistance and ESD sensitivity of the module.
Implementation Method 1
The heat generated during operation of the electronic component can be dissipated to the heat sink through the plurality of thermal plated-through holes
Implementation Method 2
The plurality of thermal plated-through holes do not have an electrical connection to the outer layer
Implementation Method 3
The heat sink is thermally connected to the multilayer printed circuit board though an electrical insulation layer
Implementation Method 4
The heat sink generally is formed of a metal for the purpose of good heat dissipation
Data Source
AI summary
An electronic module with reduced electromagnetic interference radiation includes a multilayer printed circuit board having an electrically conductive outer layer and at least one electrically conductive inner layer, an electronic component, a heat sink and a plurality of thermal plated-through holes. The electronic component is disposed on and electrically connected to the outer layer. The heat sink is thermally connected to the multilayer printed circuit board by an electrical insulation layer. Heat generated during operation of the electronic component can be dissipated to the heat sink through the plurality of thermal plated-through holes. The plurality of thermal plated-through holes do not have an electrical connection to the outer layer.