1. Introduction to PC power supply
PC power supply (Personal Computer Power Supply) refers to the power supply equipment used by the computer host, its main function is to convert alternating current into direct current that can be used by computer hardware, and can output multiple direct current with low voltage and high current, and has various protection functions, complex control circuits, and is an indispensable part of the computer system. As a branch of switching power supply, PC power supply has the characteristics of small size, light weight and high efficiency, and the stability and quality of PC power supply are directly related to the life and safety of computer hardware.
The working principle of PC power supply is to convert the input alternating current into direct current through rectification filtering and other processing methods, and then use the switching tube to change the level to output enough power to each hardware device, and at the same time carry out voltage monitoring, overload protection and power switch and other functions.
There are various classifications of PC power supplies, each type has its specific uses and characteristics, here are some common PC power classifications:
- AT Power Supply:
- The power supply used by early personal computers has been standard for PCs since the 286 era, and it was not until the 586 era that it was gradually replaced by ATX power supplies. Its power is generally between 150W~220W, and it has 2 motherboard power connectors (P8 and P9), each with 6 pins to connect the power system with the motherboard.
- ATX（Advanced Technology Extended）电源：
- The most commonly used type of power supply at present, proposed by Intel Corporation in 1995. Compared to AT power supplies, ATX power supplies have many advantages, such as providing more interfaces (such as SATA, PCIe, etc.) to meet the needs of more hardware, and adding a power management feature called Stand-By.
- BTX（Balanced Technology Extended）电源：
- PC power supply designed according to BTX standard.
- SFX（Small Form Factor）电源：
- A small power supply that is commonly used in small computers and all-in-one computers.
- TFX（Thin Form Factor）电源：
- A more compact power supply that is typically used in ultra-thin desktops and some small business PCs.
In addition, there are PC/XT power supplies, EPS power supplies, and WTX power supplies, each with its own specific application scenarios and standards.
Second, PC power supply market analysis
From the perspective of market size and growth trend, the PC power supply market is showing a steady growth trend in the world. With the proliferation of personal computers and various electronic devices, the demand for power is also increasing. Especially in emerging markets and developing countries, with the growth of the economy and the advancement of science and technology, the PC power supply market has great potential. At the same time, with the development of emerging technologies such as cloud computing, big data, and artificial intelligence, the demand for high-performance and high-reliability PC power supplies is also increasing.
From the perspective of technological development, the PC power supply market is facing the dual challenges of technological innovation and greening. On the one hand, with the improvement of the performance and the reduction of power consumption of electronic devices, the requirements for the efficiency and stability of the power supply are also increasing. Therefore, PC power supply manufacturers need to continue to carry out technological innovation to improve the conversion efficiency of power supply, reduce power consumption, reduce heat generation, etc., to meet the needs of the market. On the other hand, with the improvement of environmental awareness, greening has become an important development direction of the power supply industry. PC power supply manufacturers need to actively adopt environmentally friendly materials, optimize production processes, and promote energy-saving products to achieve sustainable development.
From the perspective of market structure, the PC power supply market presents the characteristics of diversification and centralization. On the one hand, there are many brands and manufacturers in the market, with a wide range of products and fierce price competition. On the other hand, with the intensification of market competition and the formation of economies of scale, some large manufacturers have gradually occupied the leading position in market share through technological innovation, brand building, market expansion and other means. At the same time, some small and medium-sized manufacturers focusing on market segments have also gained room for survival and development through differentiated competition and professional services.
From the perspective of market data, preliminary tracking data from IDC, an international data company, shows that after two years of decline, the global traditional PC market will resume growth in the first quarter of 2024, with shipments of 59.8 million units, a year-on-year increase of 1.5%, and global PC shipments have returned to pre-pandemic levels. The top five companies in terms of global shipments in the first quarter were Lenovo, HP, Dell, Apple and Acer, with market shares of 23%, 20.1%, 15.5%, 8.1% and 6.2%, respectively.
3. PC power supply topology and Longteng product advantages
Typically, the 80 PLUS Platinum and more efficient power supplies consist of bridgeless or semi-bridgeless PFC stages (e.g., totem pole stage), resonant DC-DC stages (e.g., LLC resonant) (see diagram below), and synchronous rectification + DC to DC.
Totem pole PFC+LLC topology
Totem pole PFC+LLC topology: the first stage of PFC circuit, when the circuit starts, the inrush current is large, requiring the MOSFET to have strong EAS capability, the high-frequency bridge arm requires good MOS switching performance, the low-frequency bridge arm requires the MOS to have small conduction, and the post-stage LLC resonant circuit requires the body diode of the MOSFET to have strong di/dt ability and small Qrr.
PC power supply market application, Longteng Semiconductor's high-voltage SJ MOS, its product advantages:
- According to the PFC topology, the EAS was optimized, the avalanche resistance was enhanced, and the surge resistance was enhanced.
- For LLC topology, the body diode is optimized, the di/dt capability is enhanced, and the Qrr and drive interference are reduced.
- The Qg and Coss/Ciss ratios are optimized to reduce drive loss and improve drive anti-interference ability.
PC power market application, Longteng Semiconductor's SGT MOS, its product advantages:
- Optimize Qg and Vth, and highly consistent Vth makes parallel connection more safe and reliable;
- Coss and Rdson are optimized to minimize switching and conduction losses and reduce temperature rise.
The above advantages make the application of Longteng products in PC power supply simple.
Fourth, PC power supply Longteng MOSFET selection table
| function | topology | Product range | Product model |
| AD-DC | PFC | 600-700V SJ MOS 650V IGBT | LSB65R041GT LSB65R070GT LSB65R099GT |
| isolation DC-DC (Beginner) | PSFB LLC DAB | LSB65R070GF LSB65R099GF LSC65R135GF | |
| isolation DC-DC (Subordinate) | Synchronous rectification 12V Vout | 40-60V SGT MOS | LSGN04R011WE LSGN04R013WE |