Controlling heat, or heat dissipation and distribution, is important to building and using PCB boards, and failure to manage heat transfer can also destroy your boards. For electronic equipment, a certain amount of heat will be generated when it works, so that the internal temperature of the equipment will rise rapidly. If the heat is not dissipated in time, the equipment will continue to heat up, the device will fail due to overheating, and the reliability of the electronic equipment will decline. Therefore, it is very important to have a good heat dissipation treatment for the circuit board. If you're interested in what this article is about to cover, read on. 1. Heat dissipation through the PCB board itself. At present, the widely used PCB board is copper-clad/epoxy glass cloth substrate or phenolic resin glass cloth substrate, and a small amount of paper-based copper-clad board is used. Although these substrates have excellent electrical properties and processability, they have poor heat dissipation properties, and as a heat dissipation path for a highly heat-generating element, heat cannot be expected to be conducted by the resin of the PCB itself, but is dissipated from the surface of the element to the surrounding air. However, as electronic products have entered the era of miniaturization of components, high-density installation and high-heat assembly, it is not enough to rely solely on the surface of components with very small surface area to dissipate heat. At the same time, due to the extensive use of surface mount components such as QFP and BGA, the heat generated by the components is transferred to the PCB board in a large amount. Therefore, the best way to solve the problem of heat dissipation is to improve the heat dissipation capacity of the PCB board itself, which is in direct contact with the heating components, and to conduct or emit it through the PCB board. 2. Add radiator and heat conducting plate to the high heating device. When there are a few devices in the PCB with large heat (less than 3), the radiator or heat conducting pipe can be added to the heating device. When the temperature can not be reduced, the radiator with fan can be used to enhance the heat dissipation effect. When the number of heating devices is large (more than 3), a large heat dissipation cover (board) can be used, which is a special radiator customized according to the position and height of the heating devices on the PCB board, or different component height positions are cut out on a large flat radiator. The heat dissipation cov is integrally buckled on that surface of the element and is in contact with each element to dissipate heat. However, due to the poor consistency of high and low components during assembly and welding, the heat dissipation effect is not good. Soft thermal phase change heat conduction pads are usually added on the surface of components to improve the heat dissipation effect. 3. For equipment using free convection air cooling, it is better to arrange the integrated circuits (or other devices) in a longitudinal manner or in a transverse manner. 4. Adopt reasonable wiring design to realize heat dissipation. Because the resin in the plate has poor thermal conductivity, and copper foil lines and holes are good conductors of heat, improving the residual rate of copper foil and increasing heat conduction holes are the main means of heat dissipation. To evaluate the heat dissipation capacity of a PCB, it is necessary to calculate the equivalent thermal conductivity (9 EQ) of an insulating substrate for a composite material, which is composed of various materials with different thermal conductivities. 5. The devices on the same printed circuit board shall be arranged in different zones according to their calorific value and heat dissipation degree as far as possible. The devices with low calorific value or poor heat resistance (such as small signal transistors, small scale integrated circuits, electrolytic capacitors, etc.) shall be placed at the upstream (inlet) of the cooling airflow. Devices with high heat generation or good heat resistance (such as power transistors, large-scale integrated circuits, etc.) are placed at the most downstream of the cooling airflow. 6. In the horizontal direction, the high-power devices shall be arranged as close as possible to the edge of the printed board to shorten the heat transfer path; In the vertical direction, the high-power devices are arranged as close as possible to the upper part of the printed board, so as to reduce the influence of these devices on the temperature of other devices during operation. 7. The heat dissipation of the printed circuit board in the equipment mainly depends on the air flow, so the air flow path should be studied in the design, and the device or printed circuit board should be reasonably configured. Air always tends to flow in a place with low resistance, so when configuring devices on the printed circuit board, it is necessary to avoid leaving a large airspace in a certain area. The configuration of multiple printed circuit boards in the whole machine should also pay attention to the same problem. 8. Devices sensitive to temperature should be placed in the area with the lowest temperature (such as the bottom of the equipment). Do not place them right above the heating devices. Multiple devices should be staggered on the horizontal plane. 9. Arrange the device with the highest power consumption and the largest heat generation near the best position for heat dissipation. Do not place devices with high heat generation in the corners and around the edges of the PCB, unless there is a heat dissipation device near it. When designing the power resistor, select a larger device as far as possible, and adjust the layout of the printed circuit board to make it have enough heat dissipation space. 10. Avoid the concentration of hot spots on the PCB, distribute the power evenly on the PCB as far as possible, and keep the surface temperature performance of the PCB uniform and consistent. It is often difficult to achieve strict uniform distribution in the design process, but we must avoid the area where the power density is too high, so as to avoid hot spots affecting the normal work of the whole circuit. If conditions permit, it is necessary to analyze the thermal performance of printed circuit boards. For example, the thermal performance index analysis software module added to some professional PCB design software can help designers optimize the circuit design. These are some of the skills and methods of heat dissipation, which need engineers to accumulate in practice. Above is to the PCB circuit board heat dissipation related introduction, hoped has the help to you.