Time saving analytical modelling and design of PCBS with through-hole and blind thermal vias

Abstract

High-power-density converters concentrate heat in smaller areas of printed circuit boards (PCBs), a challenge exacerbated by Gallium Nitride (GaN)-based components in surface-mount device (SMD) packages. While these components reduce parasitic inductance and electromagnetic interference (EMI), they also transfer heat directly to the PCB, increasing local temperatures. Traditionally, PCB thermal design relies on computational fluid dynamics (CFD), which is computationally expensive and requires multiple iterations. This paper presents an analytical thermal model to evaluate and optimise PCB thermal resistance with significantly reduced simulation time. The model examines the influence of design parameters on thermal resistance for through-hole and blind vias, identifying optimal via diameters and spacing to minimise thermal resistance while limiting impacts on copper pouring areas (and parasitic inductance). By addressing both the area beneath the heat source and its surroundings, the model provides a comprehensive understanding of PCB thermal behaviour. Validation against CFD simulations shows a deviation of only 7%, with substantially lower computational time.