SMPS Full Form: Switched Mode Power Supply

In the field of computers and electronics, the term SMPS is quite common and has been talked about a lot. SMPS is one of the important components of a computer. But the first question that comes to mind is - what is the full form of SMPS.

In this article, we will learn what SMPS is, what the SMPS full form is, a brief history of SMPS, how SMPS works, its functions, features, types, and more.

What You Will Learn

What is the full form of SMPS?

SMPS is an abbreviation used for ‘Switched Mode Power Supply’. Sometimes, it can also be referred to as ‘Switching Mode Power Supply’. SMPS is one of the important parts required for a motherboard or PCB (printed circuit board) to function in a computer system.

SMPS Full Form

The full form of the SMPS can be detailed as:

S Switched
M Mode
P Power
S Supply

Brief History about SMPS

SMPS was first introduced in 1977. It was used in Apple II. Later in 1980, SMPS was used with a synthesized signal generator providing an alternative to very lightweight computers.

In the mid-1800s, when there was no SMPS, the induction coil was the first component that helped generate high voltages. However, the use of the induction coil was replaced by several inventions over time. Before SMPS, the MOSFET (metal-oxide-semiconductor field-effect transistor) was widely used for power devices to switch power supplies. MOSFET was developed in 1959.

How does SMPS work?

SMPS uses a switching regulator to regulate and stabilize the output voltage by turning on and off load-current. The mean voltage between the two states (on and off) is the appropriate power for the device. Unlike linear power supplies, SMPS pass-transistors switch between low-dissipation, full-on & full-off states, and remain in high-dissipation cycles for very short periods, reducing energy waste to the maximum extent.

Function of SMPS

The primary function of SMPS is to convert unregulated AC or DC voltage into the computer acceptable regulated DC voltage. It uses a power control electronic mechanism to convert electrical power efficiently and minimizes the power loss. 

Characteristics of SMPS

The main characteristics of SMPS include the followings:

SMPS is highly power efficient. It provides an efficiency of around 65-70%.
SMPS is capable of handling temperature proficiently. The temperature may rise to a 20-40 degree Celsius maximum.
The magnetic material used in SMPS is known as Ferrite Core.

Types of SMPS

SMPS is mainly divided into the following four types on the basis of circuit topology:

Buck: In this type of SMPS, the current remains continuous at the output.
Boost: In this type of SMPS, the current remains continuous at the Input.
Buck-Boost: In this type of SMPS, the current on both input and output remains discontinuous.
Split-pi: In this type of SMPS, the current remains bidirectional.

Advantages of SMPS

The following are the main advantages of SMPS:

SMPS is small in size, and hence it is also lightweight.
Anti-interference in SMPS is powerful.
SMPS consumes approximately 60–70% of power, making it ideal for use.
The output range of SMPS is high, so SMPS is highly efficient.

Disadvantages of SMPS

The following are the main disadvantages of SMPS:

SMPS is very complex in nature.
SMPS consists of a single output voltage.
SMPS can only be used as a step-down regulator.
The output reflection in SMPS is high, and its management is weak.


This article states that SMPS (stands for Switched-Mode Power Supply) is one of the most important parts of a computer system, and it is not possible to start a computer without SMPS. SMPS mainly helps the computer to convert the incoming voltage into an acceptable form in the computer.

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