Thermal solution for Industrial switch
We all know that if electronic products have poor heat dissipation, the efficiency of chip operation will be greatly reduced. If it exceeds the permitted operating temperature, it will crash or even burn out the equipment. So, when designing industrial switches, we must pay enough attention to the design of heat dissipation, choose appropriate thermal solution and parameters.
The thermal design of industrial switch equipment mainly includes three types of technologies: non installation of heat sinks, installation of heat sinks, and liquid cooling.
1. No heatsink installation , usually for the low power device cooling , and design from the following three aspects to improve heat dissipation efficiency without installing a radiator:
The first method is conduction heat dissipation, which can use materials with high thermal conductivity to manufacture heat transfer components, or reduce contact thermal resistance and shorten the thermal path as much as possible.
The second type is convective heat dissipation, which includes two methods: natural convection heat dissipation and forced convection heat dissipation. Natural convection heat dissipation should pay attention to the following points: extra space must be left when designing printed circuit boards and components; When arranging components, attention should be paid to the reasonable distribution of temperature field; Increase the contact area with convective media
The third method is to utilize the thermal radiation characteristics, which can be achieved by increasing the surface roughness of the heating element, increasing the environmental temperature difference around the radiating element, or increasing the surface area of the radiating element.
This design, which does not require additional heat sinks, generally conducts the heat of the chip to the outer shell of the product, increases the heat exchange area, and plays a role in rapid cooling. At the same time, ventilation holes are also opened on the chassis, or system fans are added to increase heat exchange between the inside and outside of the chassis.
2. Adding air cooling heatsink:
By adding air cooling heatsink, we can easily get the device cooling down by active cooling or force air cooling, but we still need to considerate below points:
1. Selection of heatsink. The principle of heatsink selection is to select a heatsink with small volume and light weight as far as possible on the premise of ensuring sufficient heat dissipation, so as to save internal space and reduce the total weight of power adapter.
2. Installation of heatsink. When installing the heatink, the installation method with small heat dissipation and thermal resistance shall be selected as far as possible.
3. Minimize the thermal resistance of the interface. The surface of the heatsink shall be flat and smooth, applied with silicone grease or heat conducting gasket to reduce the contact thermal resistance between the radiator and the power semiconductor.
3. The design of cooling fan:
The fan of a regular commercial switch always operates at full speed (SPD), which not only causes energy waste and increases overall noise, but also increases unnecessary power generation and dust accumulation inside the chassis. More importantly, the lifespan of the fan at full speed is about 20000 hours, which is 2.28 years (according to data provided by SANYOFANDATASHEET). After 20000 hours, the fan speed will gradually decrease, causing instability to the entire machine. However, due to the lack of monitoring units, this hidden danger is difficult to detect. For example, when the packet loss rate of industrial switches gradually increases, it is not easy to detect that it is due to the aging of the fan, the decrease in speed, and the accumulation of too thick dust, which causes the temperature of key components inside the chassis to rise.
In the early stage of switch design, we should fully consider the operating environment of the equipment and the highest operating temperature of all electronic components, in order to set the working temperature of the heating chip. Then, when designing the structure of the motherboard and shell, we should also consider the design of the heatsink to coordinate the thermal and structural design with the best matching scheme, and meet the various requirements of equipment operation.
