What is SMPS and How Does it Work?

Today we will learn What is SMPS? Types of SMPS, Full form of SMPS, How does SMPS work? Many such questions often come to our mind, so in this post, I am going to answer some such questions related to “SMPS.” I hope you will get your answer. SMPS (Switch Mode Power Supply) is an electrical device that provides power to electronic devices and circuits. Most electronic devices used in the home or office require low power DC voltage. This led to the development of Switched Mode Power Supply (SMPS).

Everyone uses a computer today, whether it is a Desktop or laptop, but there are different parts inside it, so those parts need electricity. Still, this electricity is much less than what we use in our house, e.g., Talk TV, FRIDGE, IRON, OVEN, etc. They all use Direct up to 220V-240V, but if we give the same Voltage Direct to the parts of the computer, then everything will burn, by the way, I will tell you today how much Power the computer needs Key of Computer R Voltage how the control and angle, What is the SMPS to let us know.

This device converts High voltage AC to low voltage DC. SMPS supplies Power to various system components of the computer, such as the motherboard and device drivers. The main parts of SMPS are Power Connectors, and Power Supply Power connectors provide DC voltage to all system components, and Power Supply Fan is used to keep SMPS fresh.

What is SMPS?


The full name of SMPS is Switch Mode Power Supply. This is an Electronic Circuit; if you buy it separately for Desktop, you will get some Square Shape box, it is the same SMPS, it gives Power to different parts of Device Computer like RAM, Motherboard, Fan. By the way, the Power goes to various parts from the motherboard.

Now we know a little bit about its work, so when it first gives the main power supply to the computer from the board of the house, it first stays in the form of AC (Alternative CURRENT) and then when it is the SMPS of the AC computer. This SMPS converts it to DC; for this, he uses Capacitor and DIODE keys. With the help of the Regulator, he sometimes turns the Switch on ON, and sometimes OFF, that is, changes the Switch Mode, sometimes changes the DC to AC. CONVERT in and sometimes AC in DC; hence its name Switch Mode Power Supply The data. Now you know What is Switch Mode Power Supply.

How SMPS Works

Switched Mode Power Supply is an electrical device that supplies power to all devices in a computer such as registers or capacitors by efficiently converting power from AC to DC.

First, I go from the cable to the current computer, then first pass through the small device inside the SMPS, then first it goes to the AC filter, then they’re in the process of filtering the AC of Neutral and Phase. In between NTC, Fuse, line Filter, PF Capacitor is used, its output is given to Rectifier and Filter, which converts it from AC to DC, which was Rectifier, and the filter was with the help of two capacitors. Smooth converts to DC.

How SMPS Works

The output of this process is Pure DC, and it was given to the switching transistor. Here we use two NPN transistors, which provide one AC output with the help of the switching cycle; we give it another process. For whose name was SM transformer then this was the matter of PRIMARY CIRCUIT of SMPS.

This is then given to the Rectifier and Filter once again which converts it to this AC Supply and once again to Smooth DC (one thing to remember is that the current that comes from the transformer in the house is AC And the current in the battery is DC) The output after this action is in three forms, a 12VOLT, 5 VOLT, 3 VOLT. This is the primary and secondary circuit of SMPS.

But the rectifier and filter of the primary circuit would connect with an output starter transformer, and it would connect with the starter, which is connected with another amplifier IC. It has three output wire, the amplifier IC is an area of ​​SMPS where There is complete management work. Three significant cables are coming out of the amplifier IC; one is green, which is Power on the wire, the other comes in violet color, which gives stand by the current of +5 volt, and the third one is in gray color which has Power Bood cable Is spoken.

These three output cables are given to the motherboard. The switching transistor and amplifier IC remain connected to a driver and are controlled via the amplifier IC. From the second switching circuit comes a sensing wire, which tells the Amplifier IC that the load is increasing, then at the same time the DRIVER, which increases the SWITCHING Transmitter on-off process, and which keeps getting voltage at a constant speed. Which are + 12volt, + 5volt, and + 3volt, and this process is called switching Mode Power Supply? When the Power of green cable is on, the motherboard gets 12v, 5v, and 3v SMPS. Something like this SMPS works.

What is Direct Current and Alternative Current

By the way, the current means Flow Of Charge. There are two types.

1. Direct Current

2. Alternative Current

In Alternative Current, the flow of charge is in both directions, here it is in both positive to negative and from negative to positive, but if we talk about Direct Current, then it just flows in one direction, that is, from negative to positive. An excellent example of this is the DC that comes out of the battery used in your TV and watch. Understand a little better than the electricity that comes into your house is an example of Alternative Current, and the battery in the remote is Direct Current. If our computer needs DC Current, then to convert Alternative Current to DC, the device Used is your SMPS.

Types of SMPS

1. DC to DC Converter

2. Forward Converter

3. Flyback Converter

4. Self-Oscillating Flyback Converter

1. DC to DC Converter

This is a type of SMPS Converter in which you just have to convert the CURRENT that SMPS has to AC before converting it to DC, the current that passes through DC Converter first passes through the first side of Step Down Transformer, This step-down transformer is a part of SMPS which is 50 Hz, this voltage is rectified, and the filter hook goes to the second part of the transformer, now it goes out of the output voltage power and goes to different sections. Its output is sent back to Switch once more. To control the voltage.

2. Forward Converter

This is also a converter that carries current through a choke whether the transistor does its job or not. This diode works when the transistor is completely turned off. So this is why energy goes inside the load; it happens both off and on, but it keeps the choke energy during the ON period, and it sends some power to the output load.

3. Flyback Converter

In this Flyback Converter, the Magnetic Field of the inductor stores energy when the Switch is on. When the Switch is on, the energy output is empty in the voltage circuit. Duty Cycle determines the output voltage. That is its job.

4. Self-Oscillating Flyback Converter

This is the easiest and Basic Converter that works on Flyback. During conduction, the switching transistor increases with the transfer, primarily linearly according to a slope, which is Vin / Lp.

Depending on the type of SMPS used

The type of power supply depends on its size and usage. Its types are AT SMPS, ATx SMPS, Baby SMPS. But most AT and ATx are used more. 

Here the full name of AT SMPS is Advance Technology SMPS, and the full name of ATx SMPS is Advanced Technology Extended SMPS.

Connectors of SMPS

SMPS power connectors supply power to various components of a computer system such as motherboards, hard disk drives, and other components. The power connector is an electrical connector used to carry DC voltage. Yes, it has five types of connectors:

1. ATX Power Connectors

This is a 20 pin connector from which six types of volts are coming out. We use ATX to supply power to the motherboard. The color of the wire on the pin indicates its corresponding voltage.

2. 24 Pin SMPS Connectors:

This 24 pin SMPS connector is built with an ATX style of power connectors. This connector is used to provide power supply to the motherboard. Therefore, it is known as the PC main power connector 24 pin SMPS connector has four extra pins that take different voltage levels than 20 pin connector. Pin No. 11, 12, and 23 +12 V, +3.3 V, +5 V, and Pin No. 24 are used as ground.

3. Standard Peripheral Power Connectors (Molex):

Disk drive power connectors use four-wire connectors commonly called Molex connectors. Hard disk drives, CD / DVD drives use Molex connector I The color of the wires of the pin reflects their respective voltage.

4. SATA Power Connectors:

SATA (Serial Advanced Technology Attachment) is a power connector that connects and supplies power to a computer’s hard disk drive, CD / DVD drive. It is a 15-pin connector. A large number of pins are used for three different voltages -3.3V, 5V, and 12V. Three pins collect each energy, and there are six pins for ground.

5. PCI-E 6 Pin Connectors:

PCI-e cables are used to provide additional 12-volt power to PCI Express motherboard slots, sometimes called PCI Express Cable or PEG (PCI Express Graphics) cables.


Corsair VS450 450-Watt
Corsair VS550 550W
Corsair CP-9020172-UK VS 650W


The Output Voltage of SMPS

Different components of a computer require different voltages. Therefore SMPS provides this power supply in different quantities. The different types of voltage provided by SMPS are as under:

Blue > -12 V
White > -5 V
Black > 0 V
Orange > +3.3 V
Red > +5
Yellow > +12 V

How SMPS will be in the future

Going forward, there will be even more special SMPS that can convert the voltage well and quickly.

  • Can give more output
  • Can take a high voltage and output low voltage
  • To increase the efficiency of Power
  • Switching mode to work faster

Advantages and Disadvantages of SMPS

  • The most significant advantage of SMPS is that it is not big and full like a transformer but small and light.
    It emits much less heat than a transformer, but it also depends on its ability to function.
  • The most significant disadvantage of SMPS is that its functioning is complicated, which is very difficult to understand. If SMPS is ever wrong, then we can buy a new SMPS at the same cost as it takes to make it with a year warranty.
  • SMPS also hurts our health as it produces High-Frequency, and due to high-frequency energy, it can also cause harmonic distortion.

Video- What is SMPS


So, friends, you must have liked today’s information very much, I hope you find this information useful, and if you do hardware repair, you have even more benefits, by the way, you have become capable of What is SMPS. You can answer this question, with this SMPS, has a considerable contribution in our computer, you also know how this device works, with the help of Switch Mode Power Supply Technology and even smaller Being made so that and in smaller devices Can be applied to solve, if you still have any questions you want to ask it to write up the Comment Box below.

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