Effective thermal management

The goal of optimal thermal management is to avoid critical temperatures inside components and assemblies. The component elements must be operated within the prescribed temperature range.

In thermal management, the printed circuit board takes on an important role. It is necessary to already start thinking about suitable measures to dissipate heat in the design and development phase. In general, it is much more expensive to implement modifications and adaptations at a later point in time. There are a number of different possible ways to design systems for the heat dissipation of assemblies. They always have to be individually executed and they have to be adapted to the different requirements of the component assembly:

  • Quantity of heat that needs to be dissipated
  • Available space/dimensions of the components
  • Type of component contacts

It is possible to see similarities between electrotechnology and thermal engineering when considering thermal management. Thus voltage and temperature differences, electrical power and heat flow as well as electrical resistance and thermal resistance are certainly comparable. This is represented in the following formula:

Among other things, thermal resistance (Rth) is a function of the thickness (d), of the mediums used as well as the thermal conductivity of the material (λ) and the surface area available for heat conduction (A).

Three types of heat transfer

In electronic systems the heat produced is primarily dissipated in one of three ways: radiation, convection and conduction.

The design of the printed circuit boards has a great influence on the thermal conduction. The goal is to create the best possible thermal path with good heat conduction to the heatsink. The size of the surface area plays a positive role here.

In practice, early planning of heat dissipation technologies into the design of the printed circuit board and the component assembly has proved effective for thermal management. On the one hand, this should optimise the effectiveness and price of constructing the printed circuit board. On the other hand, it will prevent the need to make subsequent extensive modifications to the design.