A computer power supply is the heart of a computer system. Its performance and specifications directly impact the stability and energy efficiency of the entire system. With the advancement of hardware technology and the emergence of niche market demands, power supply products have developed a diverse classification system. This article will analyze the current mainstream types of computer power supplies.
1. What capacitors are used in computer power supplies?
ATX power supplies
Specifications: Standard dimensions are 150×86×140mm (width×height×depth), and they utilize a 24-pin motherboard power connector, making them the mainstream choice for desktop PCs.
Power range: 400W-1600W, meeting the needs of everything from office computers to high-end gaming consoles.
Technological evolution: The ATX 3.0 standard adds a 12V HPWR interface (supporting PCIe 5.0 graphics cards), increasing instantaneous power consumption by 200%.
SFX/SFX-L Power Supplies
Miniature Design: Dimensions are reduced to 125 × 63.5 × 100mm (SFX) or 125 × 63.5 × 130mm (SFX-L), with a weight reduction of 40% compared to ATX.
Applications: ITX mini PCs, HTPCs, and home theater PCs, with typical power draws ranging from 350W to 850W.
Cooling Challenges: Utilizes a 92mm ultra-thin fan and requires 80PLUS Gold certification or higher to reduce heat generation.
TFX/Flex-ATX Power Supplies
Ultra-thin Form Factor: TFX measures 85 × 65 × 175mm, while Flex-ATX is even smaller at 81.5 × 40.5 × 150mm.
Special Applications: Commercial all-in-one PCs, industrial control equipment, and thin clients, typically with power draws below 400W.
Technical Limitations: Due to size limitations, passive PFC designs are often used, resulting in conversion efficiencies generally below 80%.
Non-Modular Power Supply
Structural Features: All cables are directly soldered to the power supply PCB, reducing costs by 15%-20%.
Advantages and Disadvantages: Non-detachable cables make cable management difficult, but provide greater electrical connection reliability.
Suitable for: Basic office computers with a limited budget or users who don't prioritize aesthetics.
Semi-Modular Power Supply
Hybrid Design: The 24-pin motherboard and 8-pin CPU power cables are fixed, while the remaining SATA/PCIe connectors are detachable.
Engineering Value: Achieves a balance between cost and flexibility, with a market share exceeding 60%.
Fully Modular Power Supply
Core Advantages:
Increases internal chassis space utilization by 30%
Supports later expansion of RGB lighting strips or dedicated power supply for water cooling pumps
2. What Capacitors Are Used in Computer Power Supplies?
Computer power supplies use a switching power supply design. Common types of capacitors are: X-type capacitors, Y-type capacitors, ceramic capacitors, and electrolytic capacitors.
Switching Power Supply Principle
A switching power supply first rectifies and filters the input AC power into high-voltage DC. The switching power supply controller chip then rapidly switches the high-voltage DC power into a higher-frequency pulsating DC power supply. This pulsating DC power supply is then converted to low-voltage pulsating DC power via a high-frequency transformer. The low-voltage pulsating DC power supply is then rectified and filtered to produce the desired output voltage.
What capacitors are used in computer power supplies?
Computer power supply (switching power supply) circuits require X capacitors, Y capacitors, and filter capacitors. X and Y capacitors are safety capacitors used to eliminate common-mode and differential-mode interference, ensuring that the power supply meets EMC (electromagnetic compatibility) requirements. X and Y capacitors are not known to have low resistance at high frequencies.
Computer power supplies (switching power supplies) require filter capacitors in two locations: First, the input AC power needs filtering after rectification, requiring high-voltage filter capacitors. Since the input AC power is typically 50Hz or 60Hz, the operating frequency is not high, ordinary high-voltage electrolytic capacitors are sufficient for filtering. Second, the output voltage needs to filter the pulsating DC induced by the high-frequency transformer. The operating frequency here is relatively high, typically tens of kHz. To achieve optimal filtering, electrolytic capacitors with low series equivalent resistance (ESR) are required. High-frequency, low-resistance electrolytic capacitors are the best choice, as they have low equivalent impedance at higher operating frequencies.
Capacitors in power supplies are used for both high-frequency and low-frequency applications, depending on their function in the circuit. Low-frequency capacitors are generally used for filtering, and only non-polarized capacitors operating in high-frequency circuits have high operating frequencies. Furthermore, capacitors with low resistance are not commonly found. The higher the resistance, the better, as a higher resistance indicates lower leakage current.
Share our interesting knowledge and stories on social media
