Including thermal analysis early in a design process has proven to be the preferred approach in delivering the best design in the shortest amount of time. As the electrical and mechanical designs develop early in the design process the thermal analysis evolves as more information is integrated into the thermal model. Later in the design process, when ECAD data is available a more detailed approach to PCB modeling can be considered.
Accurately modeling detailed PCB traces in a system level thermal analysis is challenging. Historically the process involved the manual conversion of 2D drawings to 3D MCAD geometry. More recently thermal analysis tools have been able to convert PCB layout files directly to explicit thermal models but generally lack the ability to control the models resolution in detail. The ability to resolve a PCB layout file directly greatly reduces the model development time but modeling an entire PCB with explicit traces is computationally inefficient for most system level thermal design scenarios. The current best approach balances thermal model accuracy with computational expense through the concept of Thermal Territories.
A brief overview of the methods of capturing PCB copper distribution is discussed including the advantages and disadvantages of each process. Examples of the thermal predictions based upon these methods will be shown. The concept of Thermal Territories will be introduced and examples shown that compare the relative accuracy gain when explicitly capturing the copper distribution from the heat source outwards.