GaN Circuit Assembly Thermal Management via Copper Inlay PCB
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional GaN circuit assemblies face challenges with high thermal resistance due to the low thermal conductivity of FR4 PCBs, leading to increased drain-source on resistance and limited power delivery, as well as high conduction losses at high currents.
Innovation Solution
The proposed solution involves a circuit assembly design with a PCB featuring a copper inlay that functions as both a bus bar and a heatsink, along with double-sided cooling and copper-filled vias to reduce thermal resistance, and a separate gate-driver PCB to optimize high-current routing and thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional FR4 PCB is used for GaN circuit assembly, then manufacturing is simple and cost is low, but thermal resistance is high leading to increased drain-source on resistance and limited power delivery
Solution Approach 1:
The patent employs a composite PCB structure combining FR4 substrate with copper inlays and copper-filled vias. The copper inlays serve as both structural support and thermal conduction paths, while the copper-filled vias create vertical thermal highways from the device junctions through the PCB thickness to the heatsink. This composite approach maintains the manufacturing simplicity of FR4 while dramatically improving thermal performance and power delivery capability.
Solution Approach 2:
The copper inlays act as intermediary thermal conduction elements between the GaN devices and the heatsink. These copper traces are strategically placed underneath the devices and connected through copper-filled vias to the heatsink mounting surface, creating an efficient thermal pathway that mediates heat transfer without requiring direct device-to-heatsink contact, thus reducing thermal resistance while maintaining electrical isolation where needed.
2Loss of energy
If conventional PCB routing is used for high current, then layout is simple, but conduction losses are high
Solution Approach 1:
The patent applies local quality enhancement by inserting copper inlays at specific high-current locations rather than uniformly increasing copper throughout the entire PCB. These localized copper traces are placed precisely where high current flows (such as power delivery paths and ground returns), reducing conduction losses in critical areas while maintaining standard PCB complexity in less demanding regions. The copper-filled vias are also strategically positioned at current-dense locations to minimize resistive heating.
3Productivity
If GaN devices are mounted on conventional PCB with heatsink, then assembly is straightforward, but thermal resistance limits power density
Solution Approach 1:
The patent merges multiple functions into the PCB structure itself. The copper inlays serve dual purposes as both electrical current paths and thermal conduction channels. The copper-filled vias simultaneously provide electrical connectivity between PCB layers and serve as thermal pathways to the heatsink. This merging of electrical and thermal functions into the PCB structure enables high power density without requiring separate thermal management components, thus improving productivity while controlling device complexity.
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 design significantly reduces thermal resistance, enhances power density, and improves thermal performance, allowing for increased power delivery and reduced conduction losses, while also simplifying manufacturing and reducing costs.
Implementation Method 1
a copper inlay that functions as both a bus bar and a heatsink... copper-filled vias to reduce thermal resistance
Implementation Method 2
a heatsink attached to a second side surface of the first PCB opposite to the first side... double-sided cooling
Data Source
AI summary
A circuit assembly includes a first printed circuit board (PCB), a switching device located on a first side of the first PCB, a heatsink attached to a second side surface of the first PCB opposite to the first side, and an L-shaped metal plate attached to the heatsink and to the first PCB.