Power electronics emerged in the 1970s; prior to that, it was known as converter technology or power conversion technology. It evolved from rectification technology of the 1940s and 50s. Early players in this field included the Xi'an Rectifier Research Institute, major rectifier factories across China, and the American company International Rectifier. The predecessor of the Xi'an Rectifier Research Institute, the Semiconductor Research Laboratory of the Electrical Science Research Institute of the Ministry of Machinery Industry, was one of the earliest units in China to engage in power semiconductors. International Rectifier, founded in 1947, is also considered one of the earliest semiconductor companies in the United States. As thyristors developed into a large family of devices, and as devices with short turn-off times or easy turn-off became more advanced, inverter applications gradually became the dominant application. At this time, the academic community proposed a new discipline to categorize this development. Thus, power electronics emerged as a discipline, distinct from information electronics. The former processes information, while the latter processes power. More automatic control theories and new electronic technologies were introduced into this discipline. At that time, the applications focused on industrial applications, vehicle traction, and power systems; therefore, the primary concern was the development of high-power applications. For example, although bidirectional thyristors were already widely used in home appliances, China in the 1970s still focused on developing bidirectional thyristors for industrial applications. Subsequently, bidirectional thyristors for home appliances were not developed. In high-power semiconductors, China's gap with foreign countries has never been very large. Due to China's large-scale infrastructure construction needs, high-power semiconductor devices currently have more applications compared to foreign countries. In recent years, the introduction of several major projects has further narrowed the gap with foreign countries. This is one aspect of the development of power electronics, and perhaps a major aspect that the my country Power Electronics Society has consistently emphasized. After the rise of MOS-type devices in the early 1980s, after more than a decade of development, power electronics has increasingly covered other fields, such as the 4C industries (Communication, Computer, Consumer Appliances, and Car). At this time, the technological advancement emphasized less the power output and more the provision of more efficient, smaller, and lighter power supplies for these industries. If high-power power electronics emphasizes the execution system, low-power power electronics emphasizes the power supply. If we compare microelectronics to the brain, then large-scale power electronics emphasizes the role of the limbs, while small-scale power electronics emphasizes the role of the heart. my country's Power Supply Society naturally places greater emphasis on the latter. However, both belong to power electronics. I believe both societies are concerned with the development of power electronics in both areas. In summary, the twenty years of development of various thyristors laid the foundation for the development of power electronics in industry, drives, and power systems. Power electronics thus took shape. The subsequent twenty years of development of various MOS-type devices also laid a solid foundation for the development of the 4C industry, enabling power electronics technology to take a significant step forward. Currently, due to the further integration of microelectronics and power electronics, power semiconductor devices are taking their third step, which can be manifested in the following three aspects: 1) The chip manufacturing of new power semiconductor devices is increasingly adopting integrated circuit chip technology. In other words, power semiconductor devices are adopting submicron technology and developing towards deep submicron technology. The concept that power semiconductor devices are merely a low-level technology should now be changed. Of course, the manufacturing of power semiconductor devices did not employ the most advanced IC process technology of the time, but these differences made it possible to use cheaper equipment, thereby reducing manufacturing costs, which is very important for the development of power semiconductor devices. 2) Not only chip technology, but also the packaging technology of power semiconductor devices is converging with that of integrated circuits. In recent years, the packaging hotspots of integrated circuits have been the use of BGA (Ball Grid Array) and MCM (Multi-Chip Module) technologies, which have gradually become the packaging methods used in new power semiconductor devices. For example, IR's FlipFET and iPOWIR both use BGA technology, while iPOWIR is also the most typical MCM technology. Of course, power semiconductor devices have higher requirements for heat dissipation than integrated circuits. The double-sided heat dissipation commonly seen in thyristor packaging in the past is now being used in MOS devices for the first time, with DirectFET being one example. This article will give a brief introduction to DirectFET. 3) A new trend is that power semiconductor devices and integrated circuits are often combined in the same chip or the same package. That is to say, more functional control and power parts, or protection circuits are combined into one device. In the past, power integrated circuits primarily referred to high-voltage drive circuits, i.e., integrated circuits used to drive higher-voltage MOSFETs or IGBTs. However, a new class of integrated circuits and related power devices for power management has emerged. These may have lower voltages, but their control functions are significantly enhanced. The most typical examples are devices used in DC-DC applications. Therefore, the concept that power devices simply refer to discrete components has fundamentally changed. For example, IR's advanced devices related to ICs or with special functions have surpassed conventional discrete devices and are further developing towards the production of "systems." It is said that the production of systems and advanced devices such as ICs will become the main focus in the future. In this development process, the term "power management" has become increasingly common. The concept of power management is quite widespread abroad, especially in the power electronics industry related to the 4C industry. Its frequency of use is even higher than in traditional power electronics. Some foreign manufacturers often call themselves power management experts. This is not contradictory, as power management is simply a new term in certain areas of power electronics development at this stage. Compared to power electronics, power management emphasizes "management." The emphasis is on control functions. The word "power" can mean power, electricity, or power source. "Management" can also be understood as management or processing. Therefore, there can be many Chinese translations. However, the four Chinese characters for "power management" have appeared many times in China, which may add some trouble to standard terminology. But many foreign terms have their own development process, and new terms often emerge frequently. We should have a deeper understanding of these new terms from a technical perspective. Power conversion used to be almost synonymous with power electronics. A foreign magazine once changed its title to Power Conversion and Intelligent Motion (PCIM). However, power conversion does not fully encompass power management in power electronics. For example, power factor regulation* and low-dropout regulators (LDOs), etc. LDOs are widely used in computer power supplies for adjusting and stabilizing voltages over a small range. It is an IC that also includes power devices. For example, in an AC-DC power supply, there can be a power device with PWM and zero-voltage turn-on; it is also an IC. In IR, it is called an integrated switch. These are typical examples of IC and power device combinations. This spring, at PCIM's first conference and exhibition in China, I gave a presentation on DirectFET on behalf of my IR colleagues. This is a new hot topic for IR. I would like to give a brief introduction to this device here. As you know, there are already many surface-mount power devices. However, those packaging formats largely follow the original packaging of integrated circuits. Therefore, from a heat dissipation perspective, they are not necessarily the most suitable for power devices. DirectFET is the first to introduce double-sided heat dissipation of power devices into surface-mount devices. The size of a DirectFET is equivalent to an SO-8 case, but the resistance of the case itself is only 0.1 milliohms, while that of SO-8 is 1.5 milliohms. This doubles the current density of the device and reduces the circuit board area by 50% compared to using an SO-8 case. A synchronous buck converter composed of a pair of DirectFETs (control FET and synchronous FET) can provide 30 amps of current at 1.3 volts. The power system composed of this meets the power management requirements of Intel's latest 64-bit Itanium 2 processor. For the appearance of DirectFET, please refer to Figure 1. The diagram shows both sides of the device. One side reveals a gate and two source leads, which will be directly soldered to the circuit board. The other side is a copper cap, serving as the drain and heat dissipation surface. Figure 2 provides a cross-sectional view of the DirectFET, making its structure clearer. For those accustomed to high-power devices, the DirectFET's dimensions of only 5x6.35x0.7mm will be quite novel. This device will be used in high-end laptops, server voltage modulation modules, workstations and mainframes, and advanced communication and data systems. I would like to briefly introduce the combination of ICs and power devices in power modules at the end of this article. This can be seen as a combination of microelectronics and power electronics in the high-power field. Everyone is familiar with IPMs, the intelligent IGBT modules commonly used in air conditioners. It is essentially an IGBT module with a driver IC. Currently, newer modules are constantly emerging, forming a large family according to different needs. For example, PI-IPM refers to a programmable and isolated IPM. This type of module uses a DSP and can be programmed with software. I will provide a dedicated introduction to this family later.