PCB Technical - Causes and solutions of circuit board heating

When electronic equipment is working, heat is generated, which causes the internal temperature of the equipment to rise rapidly, and the direct cause of the temperature rise of the circuit board is the existence of circuit power consumption devices. Electronic devices have different levels of power consumption, and the heat intensity varies with power consumption. If the size changes, if the heat is not dissipated in time, the device will continue to heat up, the device will fail due to overheating, and the reliability of the electronic device will decrease. Therefore, it is very important to dissipate heat from the circuit board.

So how to solve the problem of circuit board heating? Such problems are generally solved by installing a heat sink or fan to cool the circuit board. These external accessories increase the cost and prolong the manufacturing time. Adding a fan to the design will also bring unstable factors to the reliability. Therefore, the circuit board mainly adopts active rather than passive cooling methods.

There are several ways of circuit board heat dissipation for your reference:

1. Heat dissipation through the PCB board itself.

2. High heat-generating components plus radiator and heat-conducting plate.

3. Use reasonable wiring design to realize heat dissipation.

4. 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 heating device. It is best to stagger multiple devices on the horizontal plane.

5. The heat dissipation of the printed board in the equipment mainly relies on air flow, so the air flow path should be studied during the design, and the device or printed circuit board should be reasonably configured.

6. Avoid the concentration of hot spots on the PCB, distribute the power evenly on the PCB board as much as possible, and keep the PCB surface temperature performance uniform and consistent.

7. Arrange the devices with the highest power consumption and the highest heat generation near the best position for heat dissipation.

8. For equipment that adopts free convection air cooling, it is best to arrange integrated circuits (or other devices) vertically or horizontally.

9. The devices on the same printed board should be arranged as far as possible according to their calorific value and degree of heat dissipation. Devices with low calorific value or poor heat resistance should be placed at the top of the cooling airflow (at the entrance), with large calorific value or Devices with good heat resistance (such as power transistors, large-scale integrated circuits, etc.) are placed at the most downstream of the cooling airflow.

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

11. The high heat dissipation components of the circuit board should minimize the thermal resistance between them when they are connected to the substrate. In order to better meet the thermal characteristics requirements, some thermal conductive materials (such as a layer of thermally conductive silica gel) can be used on the bottom surface of the chip, and a certain contact area can be maintained for the device to dissipate heat.