Computer power supply

Блок питания компьютера

In this article, we'll talk about one of the most important parts of the computer - the power supply unit, you'll learn what an important role it plays in a personal computer. The main function of the power supply is to convert the AC mains voltage in the household electricity network (220 V) to a constant voltage of 12 (twelve), 5 (five) and 3.3 (three) volts, which consumes the various components of our computer.

The computer power supply unit is responsible for the uninterrupted supply of electricity to the entire system unit . The failure of this node completely de-energizes the computer and it stops turning on. Either it starts to "bug" in the most unpredictable way, which is also not kosher :) A malfunctioning computer power supply can cause various "hangs", operating system errors and other programs, in short - unstable and not predictable behavior of the system as a whole. Below in the text - several photos of different power supplies:

The computer power supply, presented in the photo above, is good in that it has a large 12-cm cooler (fan) located at the bottom. With the same productivity, it rotates more slowly than the standard 8-centimeter fans located on the rear wall of the protective housing of the unit, resulting in less noise (at the same power of the air flow).

Since when the power supply is installed inside the system unit, its fan is located just above the processor and works for blowing-there is an additional heat removal from the CPU zone and hot air is ejected from the computer through round holes on the back of the unit. The longevity of such fans (12 cm) is also greater due to the smaller rotations and less wear of the bearing.

On the back wall there is also a power button to turn off the power (when buying choose this one). Firstly, it's convenient: do not disconnect the 220V cord for de-energizing. Secondly, it excludes the spontaneous switching-on of the computer in case of voltage fluctuations in the electrical network (you will agree, it will be unpleasant if the computer itself turns on and you at this time rest on the sea! :)

The photo above is also a good block for powering the computer. Look at what he has a stock of connectors (how many different devices can be simultaneously powered). There is also a button to completely turn off the power, but the 8-centimeter fan is already located on the back of the device.

Qualitative power supplies have different circuits and protection modes. We list the most popular of them:

  • UVP - (Under Voltage Protection) It works when the fall is 20-25%
  • OVP - (Over Voltage Protection) The same 25% on any of the channels, but in another row.
  • SCP - (Short Circuit Protection) Often this is just a fuse, but there are more serious solutions based on digital protection circuits
  • OPP or OLP - (Over Power Protection) Exceeds the total load across all channels.
  • OCP - (Over Current Protection - protection against surges and current surges in the network, overvoltage) Emergency disables the PSU
  • OTP - (Over Temperature Protection) The maximum temperature inside the power supply must not exceed 50 degrees Celsius.
  • AFC - (Automatic Control Fan) A separate chip that is often attached to one of the radiators
  • MTBF (Mean time Between Failures) For quality products it is more than 100,000 hours

And so it looks like an ordinary cheap Chinese power supply without an upper protective cover:

Remember: one of the signs of a quality block is its ... weight! After all, this is logical: the heavier the power supply of the computer, the more components inside it. The manufacturer did not save on the number of filter capacitors, on chokes, resistors, FETs and did not replace most of them with jumpers. Again, the thickness of the walls of the product, the number and variety of connectors, perhaps the availability of additional adapters in the delivery.

A quality computer power supply is very important! Let me give an example: in our IT department there are six computers (in one room). Two new ones, with branded blocks, the rest - so-so and one completely obsolete (for a set of documents). And so, with episodic jumps in the voltage in the mains (when the light, which is called "blinking"), we see the same picture: the oldest computer reboots instantly, the ones that are newer in 50% of cases, and two new ones almost never.

What is the secret? Exclusively in a good power supply! The fact is that high-quality products (with a short-term voltage drawdown in the power grid) can support the operation of the entire system for several tenths of a millisecond by discharging the capacitor tanks located in them.

In the presence of voltage, electrolytic capacitors accumulate a charge (are charged), and when it falls, they discharge (give up the accumulated charge), replenishing the energy loss. It is thanks to this phenomenon that a computer can safely "survive" a short-term voltage drawdown.

About computer power supplies you can add the following: many of the modern products have a connector (which is inserted into the motherboard ) not on 20 contacts (pins), like the previous generation models, but on "24 pin". It is built up by means of an additional module for four contacts, but it can also be integral.

Why is this necessary? The fact is that the development of the connector for video cards of the PCI-Express standard has led to an increase in the current supplied to it. Although most of the external graphics cards have enough power and a 20-pin connection option, the developers envisaged further development of technologies and the market and took into account the future increase in power consumption.

The additional power supplied to the PCI-Express bus, when using an additional 4-pin connector, is 76 watts. But the reality of today is that for modern graphics accelerators of the top level this is still not enough.

Many powerful power supplies now use modular cable connection to the same connectors. Than it is convenient? First of all, there is no need to keep unused cables inside the system unit itself. This, in turn, contributes to less confusion with the wires inside the enclosure (the required cable is simply added as needed).

The absence of unnecessary cables also improves the air circulation in the case. Typically, in such power supplies, only the connectors for powering the motherboard and the CPU remain fixed.

And here, for example, what part of the PSU for computers we recently received from our company:

Inside the box there is also a power cable. The block itself is "sealed" in a tight hermetic cellophane. The case, as you can see, has a convenient handle for transportation. In short, it's very functional and elegant! :)

There is another class of devices - these are power supplies for laptops. In mass, these are elements with a constant supply voltage from 12 to 24 volts (there are also 10 volt ones). On this for the time being about power supplies all, follow our other articles.