1、Intelligent switch power supply英文：With the rapid development of electronic technology, application field of electronic system is more and more extensive, electronic equipment, there are more and more people work with electronic equipment, life is increasingly close relationship. Any electronic equip
2、ment are inseparable from reliable power supply for power requirements, they more and more is also high. Electronic equipment miniaturized and low cost in the power of light and thin, small and efficient for development direction. The traditional transistors series adjustment manostat is continuous
3、control linear manostat. This traditional manostat technology more mature, and there has been a large number of integrated linear manostat module, has the stable performance is good, output ripple voltage small, reliable operation, etc. But usually need are bulky and heavy industrial frequency trans
4、former and bulk and weight are big filter.In the 1950s, NASA to miniaturization, light weight as the goal, for a rocket carrying the switch power development. In almost half a century of development process, switch power because of its small volume, light weight, high efficiency, wide range, voltage
5、 advantages in electric, control, computer, and many other areas of electronic equipment has been widely used. In the 1980s, a computer is made up of all of switch power supply, the first complete computer power generation. Throughout the 1990s, switching power supply in electronics, electrical equi
6、pment, home appliances areas to be widely, switch power technology into the rapid development. In addition, large scale integrated circuit technology, and the rapid development of switch power supply with a qualitative leap, raised high frequency power products of, miniaturization, modular tide.Powe
7、r switch tube, PWM controller and high-frequency transformer is an indispensable part of the switch power supply. The traditional switch power supply is normally made by using high frequency power switch tube division and the pins, such as using PWM integrated controller UC3842 + MOSFET is domestic
8、small power switch power supply, the design method of a more popularity.Since the 1970s, emerged in many function complete integrated control circuit, switch power supply circuit increasingly simplified, working frequency enhances unceasingly, improving efficiency, and for power miniaturization prov
9、ides the broad prospect. Three end off-line pulse width modulation monolithic integrated circuit TOP (Three switch Line) will Terminal Off with power switch MOSFET PWM controller one package together, has become the mainstream of switch power IC development. Adopt TOP switch IC design switch power,
10、can make the circuit simplified, volume further narrowing, cost also is decreased obviouslyMonolithic switching power supply has the monolithic integrated, the minimalist peripheral circuit, best performance index, no work frequency transformer can constitute a significant advantage switching power
11、supply, etc. American PI (with) company in Power in the mid 1990s first launched the new high frequency switching Power supply chip, known as the “top switch Power“, with low cost, simple circuit, higher efficiency. The first generation of products launched in 1994 represented TOP100/200 series, the
12、 second generation product is the TOP Switch - debuted in 1997 . The above products once appeared showed strong vitality and he greatly simplifies thedesign of 150W following switching power supply and the development of new products for the new job, also, high efficiency and low cost switch power s
13、upply promotion and popularization created good condition, which can be widely used in instrumentation, notebook computers, mobile phones, TV, VCD and DVD, perturbation VCR, mobile phone battery chargers, power amplifier and other fields, and form various miniaturization, density, on price can compe
14、te with the linear manostat AC/DC power transformation module.Switching power supply to integrated direction of future development will be the main trend, power density will more and more big, to process requirements will increasingly high. In semiconductor devices and magnetic materials, no new bre
15、akthrough technology progress before major might find it hard to achieve, technology innovation will focus on how to improve the efficiency and focus on reducing weight. Therefore, craft level will be in the position of power supply manufacturing higher in. In addition, the application of digital co
16、ntrol IC is the future direction of the development of a switch power. This trust in DSP for speed and anti-interference technology unceasing enhancement. As for advanced control method, now the individual feels havent seen practicability of the method appears particularly strong,perhaps with the po
17、pularity of digital control, and there are some new control theory into switching power supply.（1）The technology: with high frequency switching frequencies increase, switch converter volume also decrease, power density has also been boosted, dynamic response improved. Small power DC - DC converter s
18、witch frequency will rise to MHz. But as the switch frequency unceasing enhancement, switch components and passive components loss increases, high-frequency parasitic parameters and high-frequency EMI and so on the new issues will also be caused.（2）Soft switching technologies: in order to improve th
19、e efficiency of non-linearity of various soft switch, commutation technical application and hygiene, representative of soft switch technology is passive and active soft switch technology, mainly including zero voltage switch/zero current switch (ZVS/ZCS) resonance, quasi resonant, zero voltage/zero
20、current pulse width modulation technology (ZVS/ZCS - PWM) and zero voltage transition/zero current transition pulse width modulation (PWM) ZVT/ZCT - technical, etc. By means of soft switch technology can effectively reduce switch loss and switch stress, help converter transformation efficiency（3）Pow
21、er factor correction technology (IC simplifies PFC). At present mainly divided into IC simplifies PFC technology passive and active IC simplifies PFC technology using IC simplifies PFC technology two kinds big, IC simplifies PFC technology can improve AC - DC change device input power factor, reduce
22、 the harmonic pollution of power grid.（4）Modular technology. Modular technology can meet the needs of the distributed power system, enhance the system reliability.（5）Low output voltage technology. With the continuous development of semiconductor manufacturing technology, microprocessor and portable
23、electronic devices work more and more low, this requires future DC - DC converter can provide low output voltage to adapt microprocessor and power supply requirement of portable electronic devicesPeople in switching power supply technical fields are edge developing related power electronics device,
24、the side of frequency conversion technology, development of switch between mutual promotion push switch power supply with more than two year growth toward light, digital small, thin, low noise and high reliability, anti-interference direction. Switching powersupply can be divided into the AC/DC and
25、DC/DC two kinds big, also have AC/AC DC/AC as inverter DC/DC converter is now realize modular, and design technology and production process at home and abroad, are mature and standardization, and has approved by users, but the AC/DC modular, because of its own characteristics in the process of makin
26、g modular, meet more complex technology and craft manufacture problems. The following two types of switch power supply respectively on the structure and properties of this.Switching power supply is the development direction of high frequency, high reliability, low consumption, low noise, anti-jammin
27、g and modular. Because light switch power, small, thin key techniques are changed, so high overseas each big switch power supply manufacturer are devoted to the development of new high intelligent synchronous rectifier, especially the improvement of secondary devices of the device, and power loss of
28、 Zn ferrite (Mn) material? By increasing scientific and technological innovation, to enhance in high frequency and larger magnetic flux density (Bs) can get high magnetic under the miniaturization of, and capacitor is a key technology. SMT technology application makes switching power supply has made
29、 considerable progress, both sides in the circuitboard to ensure that decorate components of switch power supply light, small, thin. The high frequency switching power supply of the traditional PWM must innovate switch technology, to realize the ZCS ZVS, soft switch technology has become the mainstr
30、eam of switch power supply technical, and greatly improve the efficiency of switch power. For high reliability index, Americas switch power producers, reduce by lowering operating current measures such as junction temperature of the device, in order to reduce stress the reliability of products made
31、greatly increased.Modularity is of the general development of switch power supply trend can be modular power component distributed power system, can be designed to N + 1 redundant system, and realize the capacity expansion parallel. According to switch power running large noise this one defect, if s
32、eparate the pursuit of high frequency noise will increase its with the partial resonance, and transform circuit technology, high frequency can be realized in theory and can reduce the noise, but part of the practical application of resonant conversion technology still have a technical problem, so in
33、 this area still need to carry out a lot of work, in order to make the technology to practional utilization.Power electronic technology unceasing innovation, switch power supply industry has broad prospects for development. To speed up the development of switch power industry in China, we must walk
34、speed of technological innovation road, combination with Chinese characteristics in the joint development path, for I the high-speed development of national economy to make the contribution. The basic principle and component functionAccording to the control principle of switch power to classificatio
35、n, we have the following 3 kinds of work mode:1) pulse width adjustment type, abbreviation Modulation Pulse Width pulse width Modulation (PWM) type, abbreviation for. Its main characteristic is fixed switching frequency, pulse width to adjust by changing voltage 390v, realize the purpose. Its core i
36、s the pulse width modulator. Switch cycle for designing filter circuit fixed provided convenience. However, its shortcomings is influenced by the power switch conduction time limit minimum of output voltage cannot be wide range regulation; In addition, the output will take dummy loads commonly (also
37、 called pre load), in order to prevent the drag elevated when output voltage. At present, most of the integrated switch power adopt PWM way.2) pulse frequency Modulation mode pulse frequency Modulation (, referred to Pulse Frequency Modulation, abbreviation for PFM) type. Its characteristic is will
38、pulse width fixed by changing switch frequency to adjust voltage 390v, realize the purpose. Its core is the pulse frequency modulator. Circuit design to use fixed pulse-width generator to replace the pulse width omdulatros and use sawtooth wave generator voltage？Frequency converter (for example VCO
39、changes frequency VCO). It on voltage stability principle is: when the output voltage Uo rises, the output signal controller pulse width unchanged and cycle longer, make Uo 390v decreases, and reduction. PFM type of switch power supply output voltage range is very wide, output terminal dont meet dum
40、my loads. PWM way and way of PFM respectively modulating waveform is shown in figure 1 (a), (b) shows, tp says pulse width (namely power switch tube conduction time tON), T represent cycle. It can be easy to see the difference between the two. But they have something in common: (1) all use time rati
41、o control (TRC) on voltage stability principle, whether change tp, finally adjustment or T is pulse 390v. Although adopted in different ways, but control goals, is all rivers run into the sea. (2) when load by light weight, or input voltage respectively, from high changed by increasing the pulse wid
42、th, higher frequency method to make the output voltage remained stable.3) mix modulation mode, it is to point to the pulse width and switching frequency is not fixed, each other can change, it belongs to the way the PWM and PFM blend mode. It contains a pulsewidthomdulatros and pulse frequency modul
43、ator. Because and T all can adjust alone, so occupies emptiescompared to adjust the most wide range, suitable for making the output voltage for laboratories that use a wide range of can adjust switching power supply. Above 3 work collectively referred to as “Time Ratio Control“ (as a Control, from T
44、RC) way. As noted, pulse width omdulatros either as a independent IC use (for example UC3842 type pulse width omdulatros), can also be integrated in DC/DC converter (for example LM2576 type switching voltage regulators integrated circuit), still can integration in AC/DC converter (for example TOP250
45、 type monolithic integrated circuit switching power supply. Among them, the switching voltage regulators belong to DC/DC power converter, switching power supply general for AC/DC power converter.The typical structure of switch power as figure1shows, its working principle is: the first utility into p
46、ower rectifier and filtering into high voltage dc and then through the switch circuit and high-frequency switch to high frequency low pressure pulse transformer, and then after rectification and filter circuits, finally output low voltage dc power. Meanwhile in the output parts have a circuit feedba
47、ck to control circuit, through the control PWM occupies emptiescompared to achieve output voltage stability.Figure 1 typical structure of switch power supplySwitching power supply by these four components:1) the main circuit: exchange network input, from the main circuit to dc output. Mainly include
48、s input filter, rectifier and filtering, inverter, and output rectifier and filtering.(1) input filter: its effect is the power grid existing clutter filtering, also hinder the machine produces clutter feedback to public power grid.(2) rectifier and filter: the power grid ac power directly for a smo
49、oth dc rectifier, for the next level transformation.(3) inverter: will the dc after rectifying a high-frequency ac, this is the core of high frequency switching power supply, the higher the frequency, the volume, weight and the ratio of power output and smaller.(4) Out put rectifier and filter: according to load needs, providing stable and reliable dc power supply. 2) control circuit: on the one hand, from the output by The input filter Rectifier filter High frequency transformerInput rectifier filterControl circuitAuxiliary powerProtection circuit detectionAC The outputdcsampling with set
