A brief talk on power supply knowledge

Assembling a computer not only allows you to set your needs according to your own preferences, but also integrates various resources to the maximum. It is a good choice in terms of both money and enjoyment. However, many times, if you don’t know enough about computer accessories, it may cause unnecessary losses. Today, I will talk to you about some knowledge about power supplies, hoping to bring some help to your computer purchase.

Most DIY enthusiasts today are more concerned about the CPU, graphics card, motherboard and other hardware that can affect the performance of the host, but they are slightly neglected about the power supply. Some people still stay at the point where as long as the power is enough, it will be fine. However, as the source of power for the whole machine, the stability of the power supply cannot be ignored. Today, we bring you some simple analysis of power supply heat dissipation and introduce the impact of temperature on the power supply.

Power structure

A power supply is mainly composed of a shell, a circuit board (with various electronic components on it), a power socket and a fan. Its main job is to convert high-voltage AC into low-voltage DC to meet the power supply needs of the hardware. Due to technical limitations and the electronic components' own resistance to current, part of the energy will be converted into heat energy during the conversion process. High temperature will affect the accuracy and stability of electronic components, as well as the resistance, capacitance, and inductance of various electronic parts. In severe cases, it may even damage the electronic parts, thus affecting the normal operation of the power supply.

Rear oblique blowing power supply structure

Because of the influence of temperature on the operation of power supply, heat dissipation measures must be taken. The mainstream power supply products nowadays all adopt air cooling, and air cooling is divided into exhaust type, large windmill type, front-row and rear-blowing type and other forms. Let's take a look at the working principles and advantages and disadvantages of different heat dissipation methods.

Big windmill cooling

Exhaust cooling

Front-to-back cooling

Exhaust cooling uses an 8cm fan to take the heat from the chassis and power supply to the outside of the chassis, and the heat dissipation method is direct. This design technology is mature and can leave a lot of space for other electronic components in the power supply. However, since the fan is located outside the power supply and is small in size, it requires a higher speed for heat dissipation, so the noise is relatively loud.

Power supplies that use large windmills for heat dissipation generally use a 12cm fan at the bottom to suck air, blow the air around the air inlet toward the internal components of the power supply, and squeeze out the heat through the pressure generated inside the power supply. Power supplies that use large windmills for heat dissipation have low fan speeds, so the noise is relatively low, but they are prone to forming heat dissipation dead corners or accumulating heat at the bottom of the circuit board, causing uneven heat dissipation inside the power supply.

Rear oblique blowing structure heat dissipation

The front-rear blower uses two parallel convection fans to draw the hot air in the chassis through the rear fan, flow through the inside of the power supply, and then be discharged out of the chassis by the front fan. This design has excellent heat dissipation performance, but the working noise is very loud, and the power supply is larger than other heat dissipation structure power supplies.

Heat pipe cooling

Emerging Cooling Methods and Conclusions

What we have seen before are the cooling technologies widely used by current mainstream power supplies, but with the continuous innovation of technology, some emerging cooling methods have also been applied to power supply cooling.

Heat pipe + air cooling dual heat dissipation

The concept was proposed by a well-known manufacturer in the radiator industry - Overclocking Three. The rear oblique blowing structure power supply uses the airflow of the chassis duct evenly (to avoid the previous products sucking the heat emitted by the CPU into the power supply), forms direct current through the rear oblique blowing method, and the heat dissipation range covers the high-heat components, avoiding the accumulation of heat on the PCB panel (this disadvantage of the mainstream large windmill fan heat dissipation method). In addition, the built-in heat pipe and the low-speed silent fan improve the stability of the power supply output.

In fact, in addition to the heat dissipation design issues, the following points also affect the heat dissipation of the power supply:

1. Power conversion efficiency: Power conversion efficiency refers to the ratio of the input power to the output power of the power supply. If the conversion efficiency of a power supply is only 70%, the remaining 30% will be converted into heat. If it is increased to 80%, the heat will be reduced by 10%, which can reduce the temperature by 5-10 degrees. If the working environment of the power supply is increased by 10 degrees, the life span will be reduced by half. Therefore, improving the conversion efficiency of the power supply will virtually extend the life of the power supply.

2. PCB layout: PCB is the carrier of all electronic parts. Electronic components are arranged on the PCB in a certain order. If the PCB layout is not designed properly, there will be dead corners for heat dissipation.

3. Material of heat sink: Heat sinks made of different materials and shapes will have different effects on the heat dissipation of the power supply. The materials of heat sinks are divided according to conductivity: silver>copper>gold>aluminum>iron>aluminum alloy. The closer to the front, the better the thermal conductivity.

Summary: I think everyone has understood that the solution to heat dissipation should be started from the source, that is, the conversion efficiency of the power supply itself. The higher the efficiency, the lower the heat generation, which is also in line with the current trend of advocating energy conservation and environmental protection. There are power supplies with a conversion efficiency of 90% on the market, but the price is too high and ordinary players cannot accept it. However, with the development of manufacturing technology, I believe that low-carbon and environmentally friendly power supplies will gradually become popular. Finally, I remind everyone to pay attention to safety signs when choosing a power supply~