Power Electronics And Power Management

Power electronics was formed in the 1970s. Before this, people called it variable current technology, or power conversion technology. It is developed from the rectification technology in the 1940s and 1950s. Early in this industry, there are Xi'an Rectifier Research Institute, major rectifier factories across the country, the International Rectifier Company in the United States, and so on. The predecessor of Xi'an Rectifier Research Institute, the Semiconductor Research Laboratory of the Electrical Equipment Research Institute of the Ministry of Machinery is the earliest unit engaged in power semiconductors in China. The International Rectifier Company, established in 1947, is also considered to be the earliest semiconductor company in the United States. When the thyristor develops into a large family, when some devices with short turn-off time or easy to turn-off are gradually developed, the inverter application gradually rises to the dominant application. At this time, the academic community proposed that there should be a new discipline to classify this development. So there is power electronics relative to information electronics. The former deals with information and the latter deals with power. More automatic control theory and new electronic technology have also been introduced into this subject. At that time, the application direction focused on industrial applications, vehicle drag and power systems, so people are most concerned about the development of high-power direction. For example, although bidirectional thyristors have been widely used in home appliances, China still locked the development of bidirectional thyristors in the direction of industrial applications in the 1970s. After that, it did not develop into a bidirectional thyristor for household appliances. In terms of high-power semiconductors, the gap between China and foreign countries has not been very large. Due to China's massive infrastructure needs, compared with foreign countries, high-power semiconductor devices have more uses at this stage. In recent years, some major projects have been introduced, which has further shortened the gap with foreign countries. This is an aspect of the development of power electronics. It may also be a major aspect that my country Power Electronics Society has always attached importance to. After the rise of MOS-type devices in the early 1980s, after more than ten years of development, power electronics has covered more other fields, such as the 4C industry (Communication, Computer, Consumer electrical appliances, Car cars). At this time, the advancement of its technology less emphasizes the size of power, but focuses on providing these industries with more efficient, small and light power sources. If we say that high-power power electronics emphasizes the execution system, low-power power electronics emphasizes power supply. If microelectronics is likened to the brain, the large power electronics emphasize the role of hands and feet, while the small power electronics emphasize the role of the heart. The Power Supply Society of our country will naturally pay more attention to the role of the latter. But both belong to power electronics. I believe that both societies will care about the development of power electronics in two aspects. In summary, it is the twenty-year development of various thyristors, which has laid a solid foundation for the development of power electronics in industry, driving, and power systems. Power electronics is thus formed. After that, various MOS-type devices have experienced two decades of development, which also laid a solid foundation for the development of the 4C industry. Make power electronics technology a big step forward. At present, due to the further integration of microelectronics and power electronics, power semiconductor devices are taking the third step, which can be manifested in the following three aspects: 1) The chip manufacturing of new power semiconductor devices is increasingly using integrated circuit chips. Technology, in other words, power semiconductor devices are adopting sub-micron technology and developing in the direction of deep sub-micron. The concept that power semiconductor devices are just a low-level technology should now be changed. Of course, the manufacturing of power semiconductor devices did not use the most advanced IC process technology of the year, 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 power semiconductor device packaging technology is moving closer to integrated circuits. In the past few years, the hot spots for integrated circuit packaging have been the use of BGA (Ball Grid Array) and MCM (Multi-Chip Module) technologies, which have gradually become the packaging methods adopted by new power semiconductor devices. For example, IR's FlipFET and iPOWIR both use BGA technology, and 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 common in thyristor packaging in the past is now used in MOS devices for the first time. DirectFET is an example of it. Regarding DirectFET, this article will give a brief introduction to it. 3) A new trend is that power semiconductor devices and integrated circuits are often combined in the same chip or the same package. In other words, the more functional control part and power part, or protection circuit are combined in one device. In the past, the power integrated circuits that people refer to mainly refer to high-voltage drive circuits, that is, integrated circuits used to drive higher-voltage MOSFETs or IGBTs. However, a class of integrated circuits and related power devices called power management have been produced at present. The voltage may not be high, but the control function is greatly enhanced. The most typical ones are some devices in DC-DC applications. Therefore, the concept that power devices only refer to discrete devices has undergone a fundamental change. For example, advanced devices related to IC or with special functions produced by IR have surpassed conventional discrete devices, and are further developing in the direction of production "systems." There is a saying that the production of advanced devices such as systems and ICs will become the mainstay in the future. In such a development process, the term Power Management has become more and more common. The formulation of power management abroad has become quite popular, especially in the power electronics industry related to the 4C industry. The frequency of its appearance is even higher than that of the original power electronics. Some foreign manufacturers often call themselves power management experts. In fact, there is no contradiction in this respect, because power management is just a new formulation in certain fields in the current stage of power electronics development. Compared with power electronics, power management emphasizes "management." Emphasizes the function of controlling this aspect. The word Power can mean power, electricity or power. Management can also be understood as management or processing. Therefore, there can be many kinds of Chinese translations. However, the four Chinese characters for power management have appeared in China many times, which may add some trouble to the standard language. However, many foreign terms have their own development process, and many new terms often appear. We should have a deeper understanding of the emergence of these new terms from a technical perspective. Power Conversion (Power Conversion) used to be almost synonymous with power electronics. A foreign magazine once changed the title of Power Electronics to Power Conversion and Intelligent Motion (PCIM). But power conversion can't all include power management in power electronics. Such as power factor adjustment* and low dropout regulator (LDO) and so on. LDO is widely used in computer power supply as a small range voltage adjustment and stabilization. It is an IC and 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, which is also an IC. It is called Integrated Switch in IR. These are typical examples of the combination of IC and power devices. This spring, at PCIM's first report meeting and exhibition held in China, I once presented a report on DirectFET on behalf of an IR colleague. This is a new hot spot for IR. I would like to give a brief introduction to this device here. As you all know, there are already many power devices using surface mount. But those packaging forms generally follow the original packaging of integrated circuits. Therefore, from the perspective of heat dissipation, it is not necessarily the most suitable for power devices. DirectFET is the first time that the double-sided heat dissipation of power devices has been introduced into surface mount devices. The size of the DirectFET is equivalent to the SO-8 case, but the resistance of the case itself is only 0.1 milliohms, while the SO-8 is 1.5 milliohms. Therefore, the current density of the device is doubled, and the area of the circuit board is reduced by 50% compared with the original SO-8 housing. A synchronous buck converter composed of a pair of DirectFETs (control FET and synchronous FET) can provide 30 amperes of current at 1.3 volts. The resulting power system meets the power management requirements of Intel’s latest 64-bit processor Itanium2. Refer to Figure 1 for the appearance of DirectFET. The figure shows the two sides of the device, one side can see a gate and two source lead-out parts, they will be directly soldered on the circuit board. The other side is a copper cover, which is the drain and the other side that can dissipate heat. Figure 2 shows a cross-sectional view of DirectFET, so that you can understand its structure more clearly. For those who are accustomed to high-power devices, it will feel very new: DirectFET is only 5x6.35x0.7mm in size. This device will be used in high-end notebook computers, voltage modulation modules of servers, workstations and hosts, and advanced communication and data systems. I would like to briefly introduce the combination of IC and power devices in power modules at the end of this article. It can be said that this is a combination of microelectronics and power electronics for higher power. Everyone is familiar with IPM, the IGBT module with intelligence commonly used in air conditioners. It is actually an IGBT module with a driver IC. Currently updated modules are emerging one after another, forming a large family according to different needs. For example, PI-IPM refers to programmable and insulated IPM. DSP is used in this module, and software can be written. I will give a special introduction to this big family in the future.