Steady-state temperature calculation tool for multilayer PCBs

Abstract

The adoption of GaN-based devices in power converters offers significant improvements in efficiency and power density, but also intensifies thermal challenges by concentrating heat in smaller volumes. High current and compact surface-mount device packaging in GaN-based designs increase localised temperatures on printed circuit boards (PCBs), creating hotspots that can degrade materials, damage components, and compromise overall reliability. Traditional computational fluid dynamics (CFD)-based thermal analysis has been used to model PCB thermal behaviour, but its high computational cost and long setup times make it unsuitable for early-stage design. This paper introduces a MATLAB®-implemented thermal analysis tool that models PCBs as electro-thermal networks based on their hardware configuration. The tool operates in two stages: (1) an electrical network computes the current distribution and Joule heating losses across traces and vias, and (2) a thermal network uses these losses, together with power dissipation from electronic components, to calculate the temperature distribution across the PCB. The networks are coupled iteratively to account for temperature-dependent effects. The tool supports flexible configurations for layers, materials (e.g., FR4, copper, thermal vias), and heat sink (HS) integration. Validation against CFD simulations and experimental measurements confirm the accuracy of the tool in estimating temperature distributions, ensuring more effective thermal management in high-density power converters. This approach provides a fast and reliable alternative to CFD, significantly accelerating the design optimisation process.