How To Use PCB Design To Improve Heat Dissipation

      For electronic equipment, a certain amount of heat is generated during working, which causes the internal temperature of the equipment to 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 electronic equipment Performance will decrease. Therefore, good heat dissipation treatment is very important to circuit board, and following methods will be helpful.

1. Add heat dissipation copper foil and use large area power ground copper foil: the larger the area of connected copper skin is, the lower the junction temperature will be; the larger the area  covers copper is , the lower the junction temperature will be.

2. Thermal vias: Thermal vias can effectively reduce the junction temperature of the device and improve the uniformity of the temperature in the thickness direction of the board, which provides the possibility of taking other heat dissipation methods on the back of the PCB.

3. The exposed copper on the back of the IC can reduce the thermal resistance between the copper skin and the air.

4. PCB layout:

Requirements for high power, thermal devices:

a. Heat-sensitive devices are placed in the cold wind area.

b. The temperature detection device is placed in the hottest position.

c. The devices on the same printed board should be arranged according to their heat generation and heat dissipation. Devices with small heat generation or poor heat resistance (such as small signal transistors, small-scale integrated circuits, electrolytic capacitors, etc.) are placed in the uppermost part of the cooling airflow (at the entrance),  devices with large heat generation or good heat resistance (such as power transistors, large-scale integrated circuits, etc.) are placed at the downstream part of the cooling airflow.

d. In the horizontal direction, the high-power devices should be placed as close to the edge of the printed board as possible to shorten the heat transfer path; in the vertical direction, the high-power devices should be placed as close as possible to the top of the printed board to reduce the temperature impact to other devices when working.

e. The heat dissipation of the printed board in the device mainly depends on the air flow, so the air flow path should be studied in the design, and the device or the printed circuit board should be reasonably configured. When air flows, it tends to flow where there is little resistance, so when configuring devices on a printed circuit board, we should avoid leaving a large air space in a certain area. The configuration of multiple printed circuit boards in the whole machine should also pay attention to this problem.

f. The temperature-sensitive device is best placed in the lowest temperature area (such as the bottom of the device). Never place it directly above the heat-generating device. Multiple devices are best to be staggered on the horizontal plane.

g. Arrange the device with the highest power consumption and the largest heat generation near the best heat dissipation position. Do not place devices with high heat generation at the corners or surrounding edges of the printed board unless heat dissipation devices are arranged near it. When designing the power resistor, choose a larger device as much as possible, and adjust the layout of the printed circuit board to make it have sufficient heat dissipation space.