For human, we will get sick if the body temperature is too high. For electronics, the components will fail due to overheating and the reliability will decrease. Therefore, it is very important to handle the heat dissipation of the circuit board well.
In thermal design, the heat sources mainly come from three aspects:
(1) Heating of electronic components
(2) Heat generated by the PCB itself
(3) Heat from other parts
Among these three heat sources, components generate the largest amount of heat and are the main heat source, followed by the heat generated by the PCB board. The heat transferred from the outside depends on the overall thermal design of the system.
In actual PCB design, engineers need to consider heat dissipation issues including board material selection, component selection, component layout, etc. Next, this article will focus on sharing with you some heat dissipation treatments in the PCB layout design process.
Heat dissipation treatment in PCB layout design
Layout is an important part of the entire PCB heat dissipation design and plays a decisive role in PCB heat dissipation. PCB layout should be considered from the following aspects:
(1) Install components with high heat and radiation on another PCB board, so as to provide separate centralized ventilation and cooling to avoid mutual interference with the motherboard;
(2) The heat capacity of the PCB board should be evenly distributed. Do not place high-power components in a concentrated manner. If this is unavoidable, place short components upstream of the air flow and ensure that sufficient cooling air flows through the heat-concentrated area;
(3) Make the heat transfer path as short as possible;
(4) Make the heat transfer cross-section as large as possible;
(5) The layout of components should take into account the impact of heat radiation on surrounding parts. Heat-sensitive parts and components (including semiconductor devices) should be kept away from heat sources or isolated;
(6) Pay attention to the direction of forced ventilation and natural ventilation;
(7) The additional daughter boards and device air ducts must be consistent with the ventilation direction;
(8) Keep the air intake and exhaust as far apart as possible;
(9) The heating device should be placed as high as possible on top of the product, and if conditions permit, it should be in the airflow channel;
(10) Components with high heat or high current should not be placed in the corners and edges of the PCB. Install a radiator as far as possible, keep it away from other components, and ensure that the heat dissipation channel is unobstructed.
Note: Adding a heat sink to the device is also a good way to dissipate heat.
In fact, it is not just the layout process, the discussion and research on thermal design runs through the entire PCB design process. Optimize the heat dissipation effect through continuous innovation and research.