What is SMPS in Computer

We all know that is an electronic device like a computer, we cannot directly flow high voltage or say 220 Volt or 240 Volt electricity. 

Because electronic devices like TV, FRIDGE, IRON, OVEN work appropriately with 220 volts or 240-volt electricity, but if you run your computer or laptop with such high volt electricity. 

 So your device can get damaged quickly, so high volt electricity often burns the internal parts of the computer. That’s why people often use circuits to run the laptop so that high volt power does not go directly to the computer and the computer is saved from getting damaged.

What is SMPS in Computer

The full name of SMPS is (Switched Mode Power Supply) it is an electronic device, or it can also be said that it is a converter, which acts as a mediator between the main power supply of the house and the computer; it converts high voltage electricity into low voltage electricity. 

  It is converts AC to DC, as we all know that different parts of the computer need electricity to run like RAM, Motherboard and all these things in the DC voltage of electricity better works.  

SMPS is a square-shaped box in which a fan is installed, as well as many stars coming out of it. These stars provide electricity of different volts to different parts of the computer. And the fan installed in the SMPS cools it when it gets hot so that the SMPS converts high voltage AC into low voltage DC and transmits it to different parts of the computer. 

Switched Mode Power Supply or “SMPS” is a type of power supply unit (PSU), which converts unregulated AC or DC voltage into regulated DC using switching devices. SMPS uses a switching regulator to convert one form of electricity to another. 

 For example, this is the electricity that comes to our homes is an alternating current (AC). But sensitive equipment like computers requires a stable and efficient power supply. 

Therefore, SMPS is used to provide power to various components of the PC, which converts AC into static energy. We call this direct current (DC).

Main Functions of SMPS 

  • SMPS converts a wall-voltage AC power to lower voltage DC power.
  • Despite the variation in me / P voltage, it provides reliable output by regulating electric power.  
  • These are Different components inside the computer that require different amounts of electric power. SMPS Power to each part as per its requirement.

Types of SMPS

 Different kinds of SMPS include

  • DC to DC Converter 
  • Flyback Converter 
  • Forward Converter
  • Self – Oscillating flyback converter 

 DC-DC Converter  

  A constant voltage supply (VOUT) is supplied to the load, which is obtained from the primary source of the voltage supply VIN. The value of VOUT is controlled by individual resistors of the current source connected in series ( RS ) or shunt ( IS ). To control VOUT through changing IS and to keep RS constant, a significant amount of power is lost in the converter.

It is fed to a step-down transformer which is equivalent in characteristics to the weight and size of a 50Hz transformer unit. The output of the step-down transformer is provided to the forward rectifier. The filtered and rectified output DC power is used as a source for the load, and a sample of this output power is used as feedback to control the output voltage. 

With this feedback voltage, the timing of the oscillator is controlled, and there is an off.

The output of the switching power supply is controlled using PWM. 

As shown in the circuit above, the switch is driven by a PWM oscillator such that the power fed to the step-down transformer is controlled indirectly and, therefore, is used by the PWM as a pulse width signal and output. The output is regulated in. Voltages are inversely proportional to each other. 

Flyback Converter 

This type of SMPS has low output power. This is a short circuit compared to the rest of the SMPS circuit. They are used for low-power applications. Using a MOSFET, the unregulated i / p voltage is converted into the preferred o / p voltage with a continuous result. The switching frequency in this is about 100 kHz.

Forward Converter

 This is also a type of SMPS converter. Whether the transistor is doing its job correctly or not, it takes the current through the choke. When the transistor is completely turned off, the current is not taken from the choke but from the diode. 

When we turn the converter on or off, energy is supplied inside the load, but we store the choke energy with us; when the inverter is turned on, then some power goes into the output load. 

Self – Oscillating Flyback Converter 

These are a type of SMPS converter which works on the principle of the flyback converter. The switching transistor, which is VIN / LP, grows linearly as a slope during the conduction time.

Some significant parts and their functions are present inside a computer SMPS.

  • Rectifier – AC power into DC, a part converts which we call diode.  
  • Capacitor – DC converted by the rectifier and converted into smooth DC that filters the unregulated.  
  • Transformer – A transformer controls the incoming voltage up and down.  
  • Voltage Regulator – It controls the DC output, so that power, volts, and watts can be given to the computer hardware in the right amount.  
  • Hit Sink – Absorbs heat when the transistor is hot.  
  • Fuse – It protects the circuit from heavy voltage. 
  • Transistor – Its job is to switch power. 
  • Choke Coil – Works to smooth the received DC.

Connectors of SMPS

 Different types of cables or connectors are used to supply power to various components of the computer.

ATX 24 Pin Power Connector

 This connector is used to supply power to your motherboard and all its connected components such as RAM, onboard graphic card, PCI cards, etc. It has a total of 24 pins (20 + 4), in which twenty pins are separate, and four pins are different.

ATX P4 Power Connector 

The connector supplies power to the CPU installed in the motherboard. The current given by it is 12V. Usually, some motherboards have 4 pin sockets to provide power to the CPU, and some have 8 pin sockets available. That’s why it comes in 8 pins (4 + 4).  

SATA Power Connector 

This is used to supply current to SATA devices, just like Hard Disk, DVD ROM, or Drives. These connectors supply 5V and 12V power.

PCI-E Express Power Connector 

There are connectors that have 6 to 8 pins. The connectors supply power to a computer’s PCI-E Express devices like the graphics card. These connectors supply 12V power. 

Molex power connector

This is a 4Pin power connector that carries two types of supplies, 12 Volt and. It was used to power the hard drive and optical drive of the old IDE technology. 

Nowadays, this connector is rarely used. 

4pin floppy power connector

It is a small 4PIn connector found at the output of SMPS, which carries 5 Volts. It was used to power the Floppy Drive. This connector is no longer in use today.

How SMPS works

 How SMPS converts AC into DC and makes it usable for electronic devices. AC power is first input to SMPS with the help of a wire in this process. , with the help of NTC, fuse, line filter, and capacitor, stabilizing it a bit, give it to the rectifier and filter which after. Rectifier and filter converted it from AC to DC.

The output DC obtained in this step is given to the switching transistor. With the help of the NPN transistor and switching cycle, DC is once again converted into a cleaner AC. 

 This is a process that takes place in the primary circuit of the SMPS. – After this, the current is given to the rectifier and filter present in the other part of the circuit, which again converts the AC into very pure DC. 

By changing the current repeatedly, we can get stable DC power. Its rectifier and filter output are connected to the starter transformer and amplifier. 

This is the wire that comes out to power the electronic equipment.


  This article is what SMPS is. If you have any questions or suggestions related to this article, and then please tell us in the comment below. The guidance given by you are precious for us.

Leave a Reply

Your email address will not be published.

You May Also Like