Introduction to Thermal Management

In all consumer electronics, as performance increases, heat will be generated from the high speed, miniaturization & high power of the product. Heat will be generated within the semiconductor devices, power supply, driver, passive components, wires, etc. The heat has to be removed efficiently to maintain the optimal operating temperature so that the performance & efficiency of the product can be maintained. If proper thermal management is not carried out, the reliability, life span & performance of the product will be degraded significantly over time.

The common approach on heat dissipation will be by direct heat conduction where the heat generating product or electronic components will be fixed to a heatsink and/or fan to ensure optimal dissipation of the heat. In such a configuration, there has always been a wrong perception that heat transfer between the surfaces will be totally efficient. However, there will be significant heat losses in the process due to the imperfect match between the mating surfaces of the heat sink & electronic components. Even when surfaces are seemingly smooth or the heatsink’s surface has been produced by precision machining, there will still be air gaps & unevenness which may significantly reduce the overall contact surface area in the heat transfer.

To reduce heat transfer losses between the surfaces, one of the methods will be the use of thermal interface material (TIM). TIMs are placed between the surfaces to minimize the air gaps & unevenness, thus creating a thermally conductive condition to optimize the heat transfer. This will result in an efficient heat transfer from the critical heat generating components to the heatsink.

The selection of the TIM will be dependent on the actual specification of the product in-use. Some of the considerations includes:

  • Power generated 
  • Surface area of the heat source
  • Cooling capacity for cooler
  • Operating temperature for components
  • Gap available between the components & heat sink

There are different considerations for different user type:

  • Product Designer
    • In the design phase of the schematic design for the product, the selection of electronic components is important to ensure low power generation to achieve high performance. An important consideration is that the product’s users must not feel uncomfortable or affected by the heat dissipation.
    • However, thermal planning is never the priority in the design till the latter stage.
    • The use of thermal simulation software can be difficult to determine the optimal fit for an optimal thermal dissipation solution for the final product design. This also depends on the selected components, surface unevenness & TIM material types, design of cooling medium, etc. The correct selection of the TIM will improve the heat dissipation from the product itself, thus improving overall performance & life span.
  • Production/Process
    • At the production process, the product will likely be tested for reliability or accelerated stress testing before shipment.
    • In such testing environments, elevated temperature testing & intensive function programs will be used to ensure the reliability of a product before it is shipped out.
    • Thus, it will be crucial to select a suitable thermal solution which has the effective optimal heat transfer. Proper heat transfer & responsiveness must be ensured during the testing.
  • End Consumer
    • As a user, the objective is clear, the product performance cannot be compromised, e.g. lagging effect, software hang, component failure, etc.
    • The reliability of the product should be able to outlast its expected lifespan.

Effective thermal management is one of the important considerations which will contribute to the performance, reliability & the lifespan of a product.