What is SMPS and the Importance of using SMPS

In today’s article, we will know the Importance of using SMPS. function of SMPS and why is it needed in a computer? In today’s world, everyone uses computers and laptops. All these electronic things run on electricity and this power supply is provided to computers and laptops through SMPS.

In simple language, the computer gets a power supply from SMPS. It provides different voltages to each part of the computer. So let’s know Importance of using SPMS & Advantages and Disadvantages of SMPS.

Importance of using SMPS

The full form of SMPS is Switch Mode Power Supply. It is the part of a computer that supplies power to the computer. It gives power to every single component in the computer such as the motherboard, RAM, hard disk, CD / DVD drive etc.

SMPS is an electronic circuit that switches electric power. All electronic device needs the power to run and we give that power from the 220 Volt AC line of the house. But to run the circuit built inside all these electronic devices, Regulated DC power is required in different voltage ranges. To accomplish this, SMPS is installed. This SMPS works by taking 220 Volt AC Input to generate Multiple Regulated DC Voltage.

Basically, an SMPS converts Alternating Current (AC) into Direct Current (DC) and provides it to that device. Only after that electronic device can run. It is attached to the back of the computer and is attached to the power adapter in all other electronic devices such as laptops, mobiles, tablets and other gadgets.

Talking about its size, it is like a small box, and the SMPS, which is used in the adapter, is even smaller than this. Many wires come out of the SMPS installed in the computer, which supplies power to different parts of the computer. But in laptops, mobile, tablets etc. only one wire comes out of that SMPS, by which we put that device in charge.

Function of SMPS

The main function of SMPS is to supply power to computer hardware components, for which it converts AC current to DC and enables the device to run. SMPS is also called PSU (Power Supply Unit). For this reason, AC power is first inputted into the PSU through the wire.

First, a rectifier and filter are used in it. So that they convert the AC supply coming in the input to DC. That is, it converts the 220v AC supply coming into the house into 220v DC. The bridge rectifier is used here and you must know that it does not give pure DC in the output. That is, some AC components remain in that output. That’s why we use a filter circuit on it. So that it helps in extracting pure DC in the output.

After that, a chopper would have been attached. Which is made of a power electronic switch and is also called a high-frequency switch. Its switching frequency ranges from 15 to 50 Khz.

This means it can turn on and off from 15 to 50000 in 1 second. When it is on then it will send 220v and when it is off then it will send 0v. This switching technique is electrically operated. The main purpose of using it is to convert pure DC supply into variable DC.

Just after this, a step-down transformer is installed. A variable DC supply is given in this transformer. This step-down transformer reduces the voltage level and gives the required voltage to all the components in the computer. One thing is clear in the step-down transformers of SMPS, that only variable DC supply is given as input in it.

After that this reduced voltage is sent to a rectifier and filter. Because this DC voltage also has AC voltage to some extent. This reduced voltage is sent to all the components in the form of output by making pure DC through the filter.

The DC output generated is given to the chopper for feedback. After giving the output supply, there must be a doubt in your mind that why its feedback is needed. This is because whether the voltage at the output is correct or incorrect has to be monitored. That is if 12v is needed in the computer, then only 12v should come out of its output. If more or less voltage is coming out from the output then feedback is required to correct it.

Types of SMPS

Generally, we can divide SMPS into 2 types through circuit switching.

  • Isolated
  • Non-Isolated


  • In the isolated type of SMPS circuit, the switching circuit and the output are isolated.
  • In isolated-type switches, a transformer is used as an isolator between switching elements and output.
  • Multi-output SMPS can also be made using different types of transformers or tapping of transformers in this circuit.
  • The transformer can be used as a secondary energy-storing element and a separate inductor can also be used.
  • Isolated convert 2 types of types are used more. One is flyback type and the other is forward type.
  • If we change a large output voltage, the switching efficiency does not decrease in this type of circuit.


  • In this non-isolated type of SMPS circuit, the switching circuit and output are connected to each other or remain non-isolated.
  • There are 3 types of non-isolated SMPS circuits. Buck type SMPS converter, Boost type and Buck-Boost type converter.
  • In Buck type converter the output you get is less than the input.
  • Boost-type converter, the output is higher than the input.
  • In a Buck-Boost type converter, the output can be Higher and can also be lesser.
  • These types of circuits are simple. Apart from this, a single inductor is used for the energy storage element. These elements are used so that when the switching circuit is off, then only this element loses or gains its energy.
  • Two switches have to be used in this circuit. In which the switch is active, which can also be a Power BJT or POWER MOSFET and the second switch is a diode.
  • If a large output voltage is changed, then the switching efficiency in this type of circuit becomes low.

Types of Connectors in SMPS

Different power connectors of SMPS reach power to all the devices connected to the computer. All these devices consume different power, so every power connector’s socket is different.

  • 20+4 Pin ATX Power Connector
  • CPU 4+4 Pin connector
  • SATA connector
  • Peripheral 4-Pin Molex Connector
  • PCI-e 6 Pin & PCI-e 8 Pin connector

20+4 Pin ATX Power Connector

The largest power connector in SMPS is called a 20+4 pin ATX power connector. The work of this connector supplies power to the entire motherboard. This power connector is called 20+4 because earlier computers used to have 20-pin sockets. But today’s motherboards have 24-pin sockets.

CPU 4+4 Pin Connector

The CPU 4+4 pin connector has 4 pins. It gives power to the processor which is a 12v connector.

SATA Connector

The full form of the SATA connector is Serial Advance Technology Attachment. The job of this connector is to supply power to the hard drive and DVD drive.

PCI-e 6 Pin & PCI-e 8 Pin connector

This type of connector is used to provide a power supply to the graphics card. The PCI-E 6-pin connector has 75W power and the PCI-E 8-pin connector has 150W power.

Peripheral 4-Pin Molex Connector

This type of connector serves to provide a power supply to peripheral devices such as hard disks, DVD drives, floppy drives or CPU fans.

Advantages and Disadvantages of SMPS

Advantages of SMPS

  • The most important thing is it gives a power supply to the motherboard.
  • Due to its small size, it fits easily in every computer.
  • This typically includes improved power efficiency of 60 to 70 percent.
  • The biggest advantage of SMPS is that it has the ability to work because it easily overcomes the lack of low power.
  • The SMPS does not get too hot so there is a fan behind it. Which keeps the SMPS cool.

Disadvantages of SMPS

  • It can work only as a step-down transformer.
  • The function of SMPS is more complex.
  • It contains Electrical Noise of High Frequency.


I hope you have got complete information about the Importance of using SMPS from this article. Apart from this, the function of SMPS, the connector used in it, and the advantages and disadvantages of SMPS have also been explained in this article. If you have an interest in computer hardware then it will be beneficial for you.

If you do not understand anywhere in this article, then you can tell us by commenting. Also, if you want to improve or add something to this article, what is SMPS, you must tell us. If you liked this article, then share it with as many people as possible. So that this information can reach everyone. Thank you for reading this article.

Leave a Comment