What is conversion efficiency

Conversion efficiency is the ratio of the input power and output power of the power supply: the Power conversion efficiency = power supply for the host's instant output power/input power x100%. Generally speaking, the PC power supply specification has certain requirement to the conversion efficiency. PC power supply is a device that converts alternating current energy into DC power and supplies it to the host parts. Specifically, the power supply will be 220V (or 110V, etc.), 50Hz (or 60Hz) alternating current to +12v, +5v, +3.3v and -12v, +5VSB multi-channel DC, output to Accessories. This process of energy conversion is lossy, and one of the indicators of loss is conversion efficiency.

The initial power conversion efficiency is only about 60%, in the Intel ATX12V 1.3 Power supply specification, the conversion efficiency of the power supply must not be less than 68%, and in the ATX 12V 2.01, the power conversion efficiency of the higher requirements-not less than 80%. So when you buy a power supply, from the power specifications It follows, you can generally understand the power conversion efficiency of the high and low.

We know that the power supply is actually a "comprehensive transformers" composed of Transformers and AC/DC converters and corresponding voltage-stabilizing circuits. This "comprehensive Transformers" contains two main components-"Transformers" and "Current converters", and the two parts of their own electricity consumption, their ancillary voltage regulator circuit is naturally no exception, so the power itself is a "consumption of electrical appliances." The energy of the input power is not 100% converted into the effective energy for each part of the host, so there is a problem of conversion efficiency.

What you need to be aware of about conversion efficiency

1, different power supply products, the conversion efficiency is different;

2, the same power supply products, in different operating conditions, the conversion efficiency has also changed.

The 1th is very easy to understand, because different power products, their internal voltage transformer circuit, current converter and functional circuits will be different, plus their own power is not the same, so the conversion efficiency is taken for granted. But why does the conversion efficiency of the same product change? This is to start with the output voltage of the power source: Power input voltage is rated 220V, and output voltage is +12v, +5v, +3.3v different specifications, which means that the power supply at least three different ("coil ratio", "Magnetic leakage rate" Different transformers, because the power consumption of three kinds of transformers is not the same, means that the +12v, +5v and +3.3v voltage output of their respective transformer conversion efficiency is also different.

Generally speaking, the +12v voltage output is responsible for the CPU as well as the hard drive and the drive motor power supply, +5v voltage output is responsible for the hard disk and CD-ROM PCB circuit board power supply, +3.3v voltage output is the main board of the memory Circuit module power. When the computer is in different working state, the use frequency and the workload of each part will be different, which leads to the fluctuation of the work load of the voltage output circuit, so the power conversion efficiency is also changed under different working conditions.

Through the above analysis, we know that the power of their own power consumption is not very large, and the external output of the power supply is relatively large, it is generally believed that the power supply output load, unit load "allocation" of the power consumption of the smaller, at this time the conversion efficiency is higher.

Requirements for conversion efficiency of power supply specifications

The difference between conversion efficiency and PFC circuit power factor recently some powers rated their conversion efficiency as high as 98%, but a careful study found that their so-called "conversion efficiency" is actually the power factor of the active PFC circuit, which represents how much power is used by the power supply (the actual energy of the input power/ Power grid supply Energy), for the active PFC circuit, the power factor can reach 98% or even 99% of the level, and our so-called conversion efficiency, should be the power supply of other equipment energy/input power, the two objects are characterized by different.

However, here also need to note that "power factor" is not equal to "conversion efficiency." Some businesses now interpret the active 0.99 power factor as a 99% conversion efficiency, which is obviously wrong. Although both describe the concept of power saving, the meaning of the two concepts is different for individuals. PFC "power factor" high is for the country to save money, and "conversion efficiency" high is to save money for users.

Initially, the power conversion efficiency is only about 60%; in Intel's ATX12V 1.3 power supply specification, the conversion efficiency of the power supply must not be less than 68%, whereas in the ATX 12V 2.01, the conversion efficiency of the power supply is higher than that required-not less than 80%.

So when you buy a power supply, from the power specifications It follows, you can generally understand the power conversion efficiency of the high and low. There are three reasons why there is so much difference in the regulation of power conversion efficiency between the two power supply specifications:

1, the new ATX 12V 2.01 specification is based on the new electrical manufacturing technology, can achieve higher conversion efficiency;

2, because the main engine power consumption increases greatly, if the conversion efficiency of the power supply is not improved, then the large power consumption and calorific value of the machine will seriously affect the normal use;

3, the higher environmental protection and energy saving requirements.

What is the significance of pursuing high efficiency power supply

1, save energy and save electricity, both protect the environment and reduce the cost of use. For the normal running power consumption of 200W configuration, the typical load conversion efficiency from 75% to 85%, can reduce the unnecessary loss of 31W.

2, reduce the heat of the power supply, help build mute host. Switching power dissipation power, small power in the 50W level, high-power up to 150W or higher, in fact, a chassis can be compared with the CPU, graphics, a large heat source, the power of the cooling fan speed and the air volume is also comparable to high-end CPU radiator. To make the power supply fan run at a lower speed and ensure stability, it requires the efficiency of the power supply to achieve a certain level.

On the efficiency side, Intel's desktop computer Power Design Guide (PSDG) makes mandatory requirements and recommendations for conversion efficiency, which requires that conversion efficiency be no less than 65%, 72%, or 70% of the output under 20%, 50%, and 100% (honestly, no requirement), The recommended requirement is that the above three kinds of output are not less than 80% and power factor (PF) value is not less than 0.9, that is, users often hear the 80Plus standard.