One kind of internal hardware utilised in IT systems is called a PSU. Contrary to their name, power supply units (PSUs) change power rather than supply it to systems. Specifically, a power supply converts the alternating high voltage current (AC) into direct current (DC) and controls the DC output voltage to the exact tolerances required for modern computing components.
What is a PSU, or power supply unit?
Every computer system has a hardware component called a power supply unit. Its primary job is to transform external electrical power into the precise voltage and current that each component in the computer needs. In other words, it is the system's heart, providing steady and dependable power delivery that is essential to the smooth operation of the entire computing infrastructure.
What's Going on Inside a Power Supply Unit (PSU)?
Every computer system needs a power supply unit (PSU) to meet the needs of its various components. PSUs convert external electrical power into a specific voltage and current. In terms of technology, PSUs convert alternating current (AC) to direct current (DC), which is useful for computer components. Let's take a closer look at how PSUs operate.
- AC to DC Conversion: Firstly, the PSU takes in the alternating current (AC) from the standard electrical outlet, which varies depending on the region (in India, it is 230V). Next, the AC current is passed through a transformer, which steps it up or down based on the needs. Finally, the transformer prepares the current for the next step.
- Rectification: The power supply uses rectifiers, or diodes, to transform alternating current into vibrating direct current. This process is collectively referred to as rectification. If you don't remember the steps involved, don't worry. It's the same process you read about in your board class 12 curriculum.
- Smoothing: The vibrating direct current produced by rectification is not appropriate for directly powering computer components. Therefore, capacitors are used to smooth the vibrating direct current, making the direct current even more appropriate for powering computer components.
- Voltage Regulation: This circuit adjusts the voltage to meet the specifications needed by the electronic components. Although the output voltage is smoothed, there may still be some fluctuations. For this reason, voltage regulators are installed to guarantee a precise and steady output voltage. Generally speaking, the voltage ranges from 3 to 12 volts, depending on the needs of certain electrical components.
- Output: The final step involves supplying a regulated direct current (DC) voltage to all of the electronic device's components, including the motherboard, hard drives, graphics cards, and so forth. Various connectors and cables are used to distribute the output voltage or power to the various components of the device.
Power Supply Form Factors: ATX, TFX, SFX PSUs
With dimensions of 150 x 86 x 140 mm, Advanced Technology Extended (ATX) power supply form factors are intended for desktop computers and may fit into standard desktop enclosures. They are easily accessible, extensively used, and appropriate for a variety of desktop computers, but their vast size renders them useless in small situations.
2. Thin Form Extended (TFX)
With dimensions of 85 x 65 x 175 mm, Thin Form Extended (TFX) power supply form factors are smaller and thinner than ATX, making them ideal for low-profile or slender desktop systems. Small dimensions are taken into consideration during the design process. Due to their restricted availability, they are often a little more expensive than ATX PSUs.
3. Small Form Factor Extended (SFX)
With dimensions of 125 x 100 x 63.5 mm, Small Form Factor Extended (SFX) power supply form factors are even more small than TFX and ATX, making them ideal for gaming consoles and mini-ITX gaming PCs. They offer power for tiny gaming systems and are perfect for small form factor (SFF) and mini-ITX cases. However, because of their specialised design and limited power output, they are typically more expensive than bigger form factors.
What a Power Supply Unit Does
As technology has advanced, the role of the power supply unit has expanded to encompass temperature control, protection mechanisms, increasing power efficiency, and steady and dependable power delivery to computer system components. Let's start learning about each power supply unit's function one at a time.
- Voltage regulation: PSUs are responsible for ensuring that the output voltage stays within a given range in order to provide a steady power supply for the appropriate operation of computer components. Each component of a computer system requires a defined range voltage to work. Variations in voltage can seriously impair the performance of delicate electronic parts.
- Current Limiting: Current limiting is used to protect electronic components from potential harm in the event that an excessive amount of current flows, since this might cause overheating and damage to computer components. The purpose of current limiting is to guarantee that the current flow stays within the safe range, preventing equipment failure while also extending the equipment's lifespan and lowering maintenance costs.
- Overvoltage and Overcurrent Protection: These two potential hazards to electrical components also provide serious threats to equipment. Therefore, modern PSUs come equipped with a protective circuit to prevent overvoltage and overcurrent. The protective circuit's existence reduces the possibility of damage, increasing PSU dependability.
- Cooling Mechanisms: During the power conversion process, heat is produced. If this heat is accumulated over time, it can lead to overheating, which shortens the lifespan of computer components. To address this issue, power supply units (PSUs) use fans or other cooling methods to disperse the heat produced.
- Power Factor Correction (PFC): Power factor is used to quantify the efficiency with which electric power is turned into useable output. The power factor is the only goal of the power factor correction (PFC) function. When PFC is added to PSUs, power consumption efficiency rises, assisting PSUs in using power effectively while also lowering energy waste.
Types of Power Supply Units
The main technique of operation for a linear power supply is to regulate the output voltage by dissipating surplus power as heat. This method is less efficient than alternative methods since energy is not used efficiently. Currently, these power sources only regulate the voltage by absorbing the excess energy and decreasing the efficiency of the operation.
Applications: When simplicity takes precedence over maximum power efficiency, linear power supply applications come into play. Linear power supply deployment is frequent in low-power settings, when simple features are more important. These power supply units are ideal when dependable and simple power delivery is needed, but they are inapplicable when optimising energy efficiency is needed.
Audio Amplifier: Since a simple voltage control system assures a steady and dependable voltage, linear power supplies are employed in audio amplifiers.Patient Monitoring System: Because precise and continuous vital sign monitoring is necessary, linear power supplies—which give steady, dependable voltage—are utilised in patient monitoring systems.
2. Switching Power Supply
Operation: The switching power supply works by employing a high frequency switching circuit to control the output voltage through the use of a dynamin mechanism. This novel solution minimises energy waste and concurrently reduces the weight of the power supply unit, increasing efficiency.Applications: Switching power supplies are widely used in computers and other electronic devices nowadays due to their small size, capacity to minimise energy waste, increased efficiency, and exceptional suitability for applications where energy efficiency and space optimisation are crucial.
Example:
Laptop and mobile power adapters: switching power supplies are used in laptop and mobile power adapters because they are small and effective. These two features make them ideal for portable devices like laptops and mobile phones.
LED Lighting: Because switching power supplies cut down on energy waste and because LEDs require less power to operate efficiently, they are employed in LED lighting.
Power Supply Types Non Modular and Modular PSU
The terms "non-modular PSU" and "modular PSU" refer to two different types of power supply units (PSUs) based on how the cables are managed within the internal computer system and how they are connected to the PSU. These designs have no bearing on the PSU itself.
1. Non-Modular Power Supply Unit
A non-modular power supply unit is one that comes with a fixed set of cables that are permanently attached to the power supply. Because of this, non-modular power supply units are easier to use and less complicated than modular power supply units because there are fewer moving parts to worry about. They also cost less because of their straightforward design.
2. Modular Power Supply Unit
Users who frequently upgrade their systems or who wish to experiment with different cable types or lengths will find that a modular power supply unit offers them greater flexibility and customisation. The user has complete freedom to connect or disconnect cables as needed.
Different Power Supply Connectors
The ATX connection, which has 24 pins total—20 pins for the block and an extra 4 pin connector attached—is a major power connector that is crucial for powering the motherboard, CPU, RAM, and other integrated components. The ATX connector's wires are colour coded to indicate their purpose.
2. EPS Connector
Extended Power Supply, or EPS Connector, as the name implies, increases the power available to the CPU. EPS connectors come in four or eight pin varieties. In high-performance systems, where the CPU needs more power to operate effectively, an eight-pin EPS connection is typically used to provide a steady and effective power supply to the CPU.
3. PCI Express Connectors
There are three types of PCI express connectors: 6 pin, 8 pin, and 6+2 pin. 6 pin connectors can supply up to 75 watts of power to the GPU, 8 pin connectors can supply up to 150 watts of power to the GPU, and 6+2 pin connectors are a hybrid connector that can adapt to different GPU power requirements. PCI express connectors are dedicated connectors that supply power to the graphics cards (GPUs) in a computer system.
4. SATA Power Connector
Hard disc drives (HDDs), solid-state drives (SSDs), and other storage devices are a few examples of SATA (Serial ATA) devices. SATA Power Connectors are flat, L-shaped connectors that are intended to give power to SATA (Serial ATA) devices within a computer system. It does this by offering a dependable and effective power source, which guarantees steady and constant operation of linked storage devices.
5. Peripheral Connectors
The purpose of the peripheral connectors, also known as Molex connectors, is to supply power to different peripheral parts found in computer systems. Examples of these parts include fans, optical drives, and other hard drives. These are 4 pin power connectors with square-arranged pins that are still present in certain older gear and accessories but have since been superseded by SATA power connectors.
