You should be familiar with these 10 simple and practical methods for dissipating heat on PCBs.

For electronic equipment, a certain amount of heat will be generated during operation, which will cause internal temperature of equipment to rise rapidly. If heat is not dissipated in time, equipment will continue to heat up, and device will fail due to overheating, reliability of equipment will be reduced.

Therefore, it is very important to ensure good heat dissipation from PCB. PCB heat dissipation is a very important link, so what are PCB heat dissipation skills, let's discuss together below.

Copper/epoxy fiberglass base material or phenolic resin fiberglass base material is widely used for PCBs to dissipate heat through PCB itself, and a small amount of copper-coated paper-based PCB material is also used.

Although these substrates have excellent electrical and processing properties, they do not dissipate heat well. As a heat dissipation path for high-heating components, it is almost impossible to expect heat to be dissipated by resin of PCB itself, but to dissipate heat from surface of component to surrounding air.

However, as electronic products have entered era of component miniaturization, high-density installation, and high-heat assembly, it is not enough to rely on surface of components with a very small surface area to dissipate heat.

At same time, due to widespread use of surface mount components such as QFP and BGA, a large amount of heat generated by components is transferred to PCB. Therefore, best way to solve problem of heat dissipation is to improve heat dissipation ability of PCB itself, which is in direct contact with heating components, is conducted or radiated through PCB board.

▼Add copper foil for heat dissipation and copper foil for large area power supply

▼Thermal transitions

▼The back of chip is copper-plated to reduce thermal resistance between copper shell and air

PCB layout

Place heat-sensitive components in a cool place.

The device for determining temperature is in hottest place.

Devices on same PCB should be located as far as possible according to their calorific value and degree of heat dissipation. capacitors, etc.) In upstream (inlet) of cooling air stream, devices with high heat dissipation or good heat resistance (such as power transistors, large integrated circuits, etc.) are placed at very bottom of cooling air stream .

In horizontal direction, powerful devices are located as close to edge of PCB as possible to shorten heat transfer path; in vertical direction, powerful devices are located as close as possible to edge of PCB. top of circuit board to reduce impact on other devices when those devices are working. The effect of temperature.

The heat dissipation of printed circuit boards in equipment is mainly dependent on airflow, so airflow path should be considered in design, and components or circuit boards should be reasonably located.

When air moves, it always tends to flow where there is little resistance, so when placing devices on a PCB, avoid leaving a large airspace in a certain area. The configuration of multiple PCBs in whole machine should also pay attention to same problem.

The temperature device is best placed in area with lowest temperature (for example, on bottom of device). Never place it directly above a heating device. It is best to place several devices in a checkerboard pattern on a horizontal plane.

Place components that dissipate most energy and generate most heat near areas where heat is best dissipated. Do not place heat dissipating devices on corners and edges of a PCB unless there is a heatsink near it.

When designing a power resistor, choose as large a device as possible and allow enough space for heat dissipation when setting up PCB layout.

Suggested spacing between components:

Add heatsinks and heat sinks to hot components. When there are several components on PCB that generate a lot of heat (less than 3), you can add heatsinks or heatpipes to heating components. temperature cannot drop. A heatsink with a fan can be used to enhance cooling effect.

If there are a large number of heating elements (more than 3), you can use a large heat-dissipating cover (board), which is a special heatsink configured according to position and height of heating elements on printed circuit board or in a large one. Cut components of different heights on a flat radiator. Attach cooling cover to surface of component as a whole and touch each component to dissipate heat.

However, effect of heat dissipation is small due to poor coordination of components during their assembly and soldering. Usually, a phase change soft thermal pad is added to surface of component to improve heat dissipation effect.

For equipment cooled by free convection air, it is best to place integrated circuits (or other devices) either along or to side.

Adopt reasonable wiring design to achieve heat dissipation. Since resin in board has poor thermal conductivity, and copper foil lines and holes are good heat conductors, increasing residual coefficient of copper foil and increasing thermal conduction holes are main means of heat dissipation. To evaluate ability of a printed circuit board to dissipate heat, it is necessary to calculate equivalent thermal conductivity (nine equivalents) of insulating substrate for a printed circuit board, which is a composite material consisting of various materials with different thermal conductivity.

Devices on same PCB should be located as far as possible according to their calorific value and degree of heat dissipation. capacitors, etc.) In upstream (inlet) of cooling air stream, devices with high heat dissipation or good heat resistance (such as power transistors, large integrated circuits, etc.) are placed at very bottom of cooling air stream .

In horizontal direction, high power devices are placed as close to edge of PCB as possible to shorten heat transfer path; in vertical direction, powerful devices are located as close as possible to edge of printed circuit board. can on top of circuit board to reduce impact on other devices when these devices are working. The effect of temperature.

The heat dissipation of printed circuit boards in equipment is mainly dependent on airflow, so airflow path should be considered in design, and components or circuit boards should be reasonably located.

When air moves, it always tends to flow where there is little resistance, so when placing devices on a PCB, avoid leaving a large airspace in a certain area.

The configuration of multiple PCBs throughout machine should also account for same problem.

The temperature device is best placed in area with lowest temperature (for example, on bottom of device). Never place it directly above a heating device. It is best to place several devices in a checkerboard pattern on a horizontal plane.

Place components that dissipate most energy and generate most heat near areas where heat is best dissipated. Do not place heat dissipating devices on corners and edges of a PCB unless there is a heatsink near it. When designing a power resistor, choose as large a device as possible and provide enough space for heat dissipation when setting up PCB layout.

Avoid concentrating hot spots on PCB, distribute power as evenly as possible across PCB, and keep PCB surface temperature uniform and consistent.

It is often difficult to achieve a strict uniform distribution during design process, but areas with too high power density must be avoided to avoid hot spots that affect normal operation of entire circuit.

If possible, analyze thermal characteristics of printed circuit boards. For example, thermal performance index analysis software module added to some professional PCB design software can help designers optimize circuit designs.