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1、精选优质文档-倾情为你奉上 毕业论文英文翻译资料题 目： 直流开关稳压电源的保护技术 院 （系）： 电气与信息工程学院 专 业： 电气工程及其自动化 学生姓名： 冯启立 班 级： 电气1144 学 号： 指导教师： 郭大业 何希才.新型开关电源设计与应用M.北京:科学出版社,2001.专心-专注-专业DC Switching Power Supply Protection TechnologyAbstract: The DC switching power supply protection system, protection system design principles and mac
2、hine protection measures, an analysis of switching power supply in the range of protected characteristics and its design methodology, introduced a number of practical protection circuit.Keywords: switching power supply protection circuit system designA、IntroductionDC switching regulator used in the
3、price of more expensive high-power switching devices, the control circuit is also more complex, In addition, the load switching regulators are generally used a large number of highly integrated electronic systems installed devices. Transistors and integrated device tolerance electricity, less heat s
4、hocks. Switching Regulators therefore should take into account the protection of voltage regulators and load their own safety. Many different types of circuit protection, polarity protection, introduced here, the program protection, over-current protection, over-voltage protection, under-voltage pro
5、tection and over-temperature protection circuit. Usually chosen to be some combination of protection, constitutes a complete protection system.B、Polarity protectionDC switching regulator input is generally not regulated DC power supply. Operating errors or accidents as a result of the situation will
6、 take its wrong polarity; switching power supply will be damaged. Polarity protection purposes, is to make the switching regulator only when the correct polarity is not connected to DC power supply regulator to work at. Connecting a single device can achieve power polarity protection. Since the diod
7、e D to flow through switching regulator input total current, this circuit applied in a low-power switching regulator more suitable. Power in the larger occasion, while the polarity protection circuit as a procedure to protect a link, save the power required for polarity protection diodes, power cons
8、umption will be reduced. In order to easy to operate, make it easier to identify the correct polarity or not, collect the next light.C、Procedures to protect Switching power supply circuit is rather complicated, basically can be divided into low-power and high-power part of the control part of the sw
9、itch. Switch is a high-power transistors, for the protection of the transistor switch is turned on or off power safety, we must first modulator, amplifier and other low-power control circuit. To this end, the boot to ensure the correct procedures. Switching Regulators generally take the input of a s
10、mall inductor, the input filter capacitor. Moment in the boot, filter capacitor will flow a lot of surge current, the surge current can be several times more than the normal input current. Such a large surge current may contact the general power switch or relay contact melting, and the input fuse. I
11、n addition, the capacitor surge current will damage to shorten the life span of premature damage. To this end, the boot should be access to a current limiting resistor, through the current limiting resistor to capacitor charging. In order not to make the current limiting resistor excessive power con
12、sumption, thus affecting the normal switching regulator, and the transient process in the boot after a short period then automatically relays it to DC power supply directly to the switching regulator power supply. This circuit switching regulator called a soft start circuit.Switching regulator contr
13、ol circuit of the logic components required or op-amp auxiliary power supply. To this end, the auxiliary power supply must be in the switch circuit. This control circuit can be used to ensure the boot. Normal boot process is: to identify the polarity of input power, voltage protection procedures boo
14、t auxiliary power supply circuit and through current limiting resistor R of the switching regulator input capacitor C charge modulation switching regulator circuit, short-circuit current limiting resistor stability switching regulator.In the switching regulator, the machines just because the output
15、capacitance, and charge to the rated output voltage value of the need for a certain period of time. During this time, sampling the output amplifier with low input voltage sampling, closed-loop regulation characteristics of the system will force the switching of the transistor conduction time lengthe
16、ned, so that switching transistor during this period will tend to continuous conduction, and easily damaged. To this end, the requirements of this paragraph in the boot time, the switch to switch the output modulation circuit transistor base drive signal of the pulse width modulation, can guarantee
17、the switching transistor by the cut-off switches are becoming more and more normal state, therefore the protection of the setting up of a boot to tie in with the soft start.D、Over-current protection When the load short-circuit, overload control circuit failure or unforeseen circumstances, such as wo
18、uld cause the flow of switching voltage regulator transistor current is too large, so that increased power tubes, fever, if there is no over-current protection device, high power switching transistor may be damaged. Therefore, the switching regulator in the over-current protection is commonly used.
19、The most economical way is to use simple fuse. As a result of the heat capacity of small transistors, general fuse protection in general can not play a role in the rapid fuse common fuse. This method has the advantage of the protection of vulnerable, but it needs to switch transistor in accordance w
20、ith specific security requirements of the work area to select the fuse specifications. This disadvantage is over-current protection measures brought about by the inconvenience of frequent replacement of fuses.Linear voltage regulator commonly used in the protection and current limiting to protect th
21、e cut-off in the switching regulator can be applied. However, according to the characteristics of switching regulators, the protection circuit can not directly control the output transistor switches, and over current protection must be converted to pulse output commands to control the modulator to p
22、rotect the transistor switch. In order to achieve over-current protection are generally required sampling resistor in series in the circuit, this will affect the efficiency of power supply, so more for low-power switching regulator of occasions. In the high-power switching power supply, by taking in
23、to account the power consumption should be avoided as far as possible access to the sampling resistor. Therefore, there will usually be converted to over-current protection, and under-voltage protection. E、Over-voltage protection Switching regulators input over-voltage protection, including over-vol
24、tage protection and output over-voltage protection. Switching regulator is not used in DC power supply voltage regulator and rectifier, such as battery voltage, if too high, so switching regulator is not working properly, or even damage to internal devices, therefore, it is necessary to use the inpu
25、t over-voltage protection circuit. Using transistors and relays protection circuit.In the circuit, when the input DC power supply voltage higher than the voltage regulator diode breakdown voltage value, the breakdown voltage regulator tube, a current flowing through resistor R, so that V turn-on tra
26、nsistor, relay, normally closed contact off open, cut off the input. Voltage regulator voltage regulator which controls the value of Vs. = Earwax-UBE. The polarity of input power with the input protection circuit can be combined with over-voltage protection, polarity protection constitute a differen
27、tial circuit and over voltage protection. Output over-voltage protection switching power supply is essential. In particular, for the 5V output of the switching regulator, it is a lot of load on a high level of integration of the logic device. If at work, switching regulator sudden damage to the swit
28、ch transistor, the output potential may be increased immediately to the importation of non-regulated DC power supply voltage value, causing great loss instantaneous. Commonly used method is short-circuit protection thirsted. The simplest over-voltage protection circuit. When the output voltage is to
29、o high, the regulator tube breakdown triggered thirstier turn-on, the output short-circuit, resulting in over-current through the fuse or circuit protective device to cut off the input to protect the load. This circuit is equivalent to the response time of the opening time of thirstier is about 5 10
30、s. The disadvantage is that its action is fixed voltage, temperature coefficient, and action points of instability. In addition, there is a voltage regulator control parameters of the discrete, model over-voltage start-up the same but has different values, difficult to debug. Esc a sudden increase i
31、n output voltage, transistors V1, V2 conduction, the thruster conduction. Reference voltage Vs. by type.F、Under-voltage protection Output voltage below the value to reflect the input DC power supply, switching regulator output load internal or unusual occurrence. Input DC power supply voltage drops
32、below the specified value would result in switching regulator output voltage drops, the input current increases, not only endanger the switching transistor, but also endanger the input power. Therefore, in order to set up due to voltage protection. Due to simple voltage protection. When no voltage r
33、egulator input normal, ZD breakdown voltage regulator tube, transistors V conduction, the relay action, contact pull-in, power-switching regulator. When the input below the minimum allowable voltage value, the regulator tube ZD barrier, V cut-off, contact Kai-hop, switching regulator can not work. I
34、nternal switching regulator, as the control switch transistor circuit disorders or failure will decrease the output voltage; load short-circuit output voltage will also decline. Especially in the reversed-phase step-up or step-up switching regulator DC voltage of the protection due to over-current p
35、rotection with closely related and therefore more important. Implementation of Switching Regulators in the termination of the output voltage comparators.Normally, there is no comparator output, once the voltage drops below the allowable value in the comparator on the flip, drive alarm circuit; also
36、fed back to the switching regulator control circuit, so that switching transistor cut-off or cut off the input power. G、Over-temperature protection Switching regulator and the high level of integration of light-weight small volume, with its unit volume greatly increased the power density, power supp
37、ly components to its work within the requirements of the ambient temperature is also a corresponding increase. Otherwise, the circuit performance will deteriorate premature component failure. Therefore, in high-power switching regulator should be set up over-temperature protection. Relays used to de
38、tect the temperature inside the power supply temperature, when the internally generated power supply overheating, the temperature of the relay on the action, so that whole circuit in a warning alarm, and the realization of the power supply over-temperature protection. Temperature relay can be placed
39、 in the vicinity of the switching transistor, the general high-power tube shell to allow the maximum temperature is 75 , adjust the temperature setting to 60 . When the shell after the temperature exceeds the allowable value to cut off electrical relay on the switch protection. Semiconductor switchi
40、ng device thermal hot thirstier, in the over-temperature protection, played an important role. It can be used as directed circuit temperature. Under the control of p-hot-gate thirstier (TT102) characteristics, by RT value to determine the temperature of the device turn-on, RT greater the temperature
41、 the lower the turn-on. When placed near the power switching transistor or power device, it will be able to play the role of temperature instructions. When the power control the temperature of the shell or the internal device temperature exceeds the allowed value, the heat conduction thirstier on, s
42、o that LED warning light. If the opt coupler with, would enable the whole circuit alarm action to protect the switching regulator. It can also be used as a power transistor as the over-temperature protection, crystal switch the base current by n-type gate control thirstier TT201 thermal bypass, cut-
43、off switch to cut off the collector current to prevent overheating.H、The future development of relay protectionProtection technology to future trends is computerized, network, intelligent, protection and control, measurement and data communications integration development.1) ComputerizedAlong with t
44、he rapid development of computer hardware, microcomputer protection and development in hardware. Former north electricity institute of computer line protection hardware has experienced three development stages: from eight single CPU structure of the microcomputer relay protection, less than 5 years
45、time to develop more CPU structure, and to develop the large dont bus module, performance greatly improve module structure, widely used. Huazhong university of science and technology development of microcomputer protection from 8 bits CPU, is the core part in polymerizing-kettle development based on
46、 32-bit microcomputer protection.Nanjing institute of electrical automation began a 16-bit CPU is developed on the basis of computer line protection, has been widespread in the study, also protect the hardware system 32 bits. The development of southeast university computer hardware and equipment to
47、 protect and improve through a lot. Tianjin university is a start with more than 16 bits CPU developed on the basis of computer line protection, which began in 1988 study 32-bit digital signal processor (DSP) for the protection and control, measuring devices, microcomputer integrated with Zhuhai jin
48、 electrical automation equipment company developed into a fully functional 32-bit big modules, a module is a small computer. Using 32-bit microcomputer chip is not only because the accuracy and precision of the A/D converter by the resolution limit, more than 16 when converting speed and cost is una
49、cceptable, More important is the 32-bit microcomputer chip with high integrity, high frequency and computing speed and large space, rich addressing the command system and more input output. The CPU registers, data bus, the address bus are 32-bit memory management function, and memory protection function and tasks, and the