直流开关稳压电源的保护技术外文翻译

1、translated from: xiongfusheng, dc switching power supply protection technology, guangzhou:the world of power supply p,2002.2.dc switching power supply protection technologyabstract: the dc switching power supply protection system, protection system design principles and machine protection measures,

2、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 design1、introduction dc switching regulator used in the price of more expensive h

3、igh-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 shocks. switching regulato

4、rs 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 protection and over-temperat

5、ure protection circuit. usually chosen to be some combination of protection, constitutes a complete protection system.2、polarity protection dc switching regulator input are generally not regulated dc power supply. operating errors or accidents as a result of the situation will take its wrong polarit

6、y, 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 diode d to flow through swi

7、tching 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 consumption will be reduced

8、. in order to easy to operate, make it easier to identify the correct polarity or not, collect the next light.3、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 switch. switch is a high-

9、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 small inductor, the inpu

10、t 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 fuse. in addition, the ca

11、pacitor 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 consumption, thus aff

12、ecting 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 control circuit of the

13、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 boot auxiliary power

14、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 capacitance, and c

15、harge 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 lengthened, so that switc

16、hing 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 the switching tran

17、sistor 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.4、over-current protection when the load short-circuit, overload control circuit failure or unforeseen circumstances, such as would cause the flow

18、 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. the most economica

19、l 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 with specific secur

20、ity 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 the cut-off in the s

21、witching regulator can be applied. however, according to the characteristics of switching regulators, the protection circuit can not directly control the output transistor switches, and overcurrent protection must be converted to pulse output commands to control the modulator to protect the transist

22、or 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 into account the powe

23、r 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. 5、over-voltage protection switching regulators input over-voltage protection, including over-voltage protection and

24、 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 input over-voltage prot

25、ection 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 transistor, relay, nor

26、mally closed contact off open, cut off the input. voltage regulator voltage regulator which controls the value of vz = esrmax-ube. the polarity of input power with the input protection circuit can be combined with over-voltage protection, polarity protection constitute a differential circuit and ove

27、rvoltage 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 switch transistor, the ou

28、tput 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 thyristor. the simplest over-voltage protection circuit. when the output voltage is too high, the regulato

29、r tube breakdown triggered thyristor 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 thyristor is about 5 10s. the disadvantage

30、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 in output voltage, tr

31、ansistors v1, v2 conduction, the thyristor conduction. reference voltage vz by type.6、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 below the specified

32、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 regulator input norma

33、l, 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. internal switching re

34、gulator, 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 protection with close

35、ly 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 fed back to the swit

36、ching regulator control circuit, so that switching transistor cut-off or cut off the input power. 7、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 supply components to its

37、 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 detect the temperatur

38、e 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 in the vicinity of

39、 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 switching device thermal h

40、ot thyristor, in the over-temperature protection, played an important role. it can be used as directed circuit temperature. under the control of p-hot-gate thyristor (tt102) characteristics, by rt value to determine the temperature of the device turn-on, rt greater the temperature the lower the turn

41、-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 thyristor on, so that led warning

42、light. if the optocoupler 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 thyristor tt201 thermal bypass, cut-off switch to cut o

43、ff the collector current to prevent overheating.8、conclusion discussed above in the switching regulator of a variety of conservation, and introduces a number of specific ways to achieve. of a given switching power supply is concerned, but also protection from the whole to consider the following poin

44、ts: 1) the switching regulator used in the switching transistor in the dc security restrictions on the work of regional work. the transistor switches selected by the manual available transistors get dc safe working area. according to the maximum collector current to determine the input value of over

45、-current protection. however, the instantaneous maximum value should be converted to the average current. at rated output current and output voltage conditions, the switch of the dynamic load line does not exceed a safe working area dc maximum input voltage, input over-voltage protection is the volt

46、age value. 2) the switching regulator output limit given by the technical indicators within. work within the required temperature range, the switching regulators output voltage, the lower limit of the output is off, due to the voltage value of voltage protection. over-current protection can be based

47、 on the maximum output current to determine. false alarm in order not to protect the value of a certain margin to remain appropriate. 3) from the above two methods to determine the protection after the power supply device in accordance with the needs of measures to determine the alarm. measures the

48、general alarm sound and light alarm two police. voice of the police applied to more complex machines, power supply parts and do not stand out in a place, it can give staff an effective warning of failure; optical police instructions can be eye-catching and fault alarm and pointed out that the fault

49、location and type. protection measures should be protected as to determine the location. in the high-power, multi-channel power supply, always paying, dc circuit breakers, relays, etc. high-sensitivity auto-protection measures, to cut off the input power supply to stop working the system from damage

50、. through the logic control circuit to make the appropriate program cut-off switch transistor is sensitive it is convenient and economic. this eliminated large, long response time, the price of your high-power relay or circuit breaker. 4) the power of putting in the protection circuit will be affect

51、ed after the reliability of the system, for which want to protect the reliability of the circuit itself is higher in order to improve the reliability of the entire power system, thereby increasing its own power supply mtbf. this requires the protection of strict logic, the circuit is simple, at leas

52、t components, in addition to the protection circuit should also be considered a failure of maintenance of their difficulty and their power to protect the damage. therefore, we must be comprehensive and systematic consideration of a variety of switching power supply protection measures to ensure the

53、normal operation of switching power supplies and high-efficiency and high reliability.译自：熊福生，直流开关电源保护技术，广州：电源世界期刊p，2002.2直流开关稳压电源的保护技术摘 要：讨论了直流开关稳压电源的保护系统,提出保护系统设计的原则和整机保护的措施，分析了开关稳压电源中的各种保护的特点及其设计方法,介绍了几种实用保护电路。关键字：开关电源 保护电路 系统设计1、引言直流开关稳压器中所使用的大功率开关器件价格较贵,其控制电路亦比较复杂,另外,开关稳压器的负载一般都是用大量的集成化程度很高的器件安装

54、的电子系统。晶体管和集成器件耐受电、热冲击的能力较差。因而开关稳压器的保护应该兼顾稳压器本身和负载的安全。保护电路的种类很多,这里介绍极性保护、程序保护、过电流保护、过电压保护、欠电压保护以及过热保护等电路。通常选用几种保护方式加以组合,构成完善的保护系统。2、极性保护直流开关稳压器的输入一般都是未稳压直流电源。由于操作失误或者意外情况会将其极性接错,将损坏开关稳压电源。极性保护的目的,就是使开关稳压器仅当以正确的极性接上未稳压直流电源时才能工作。利用单向导通的器件可以实现电源的极性保护。最简单的极性保护电路如图1所示。由于二极管d要流过开关稳压器的输入总电流,因此这种电路应用在小功率的开关稳

55、压器上比较合适。在较大功率的场合,则把极性保护电路作为程序保护中的一个环节,可以省去极性保护所需的大功率二极管,功耗也将减小。为了操作方便,便于识别极性正确与否,在二极管之后接指示灯。3、程序保护开关稳压电源的电路比较复杂,基本上可以分为小功率的控制部分和大功率的开关部分。开关晶体管则属大功率，为保护开关晶体管在开启或关断电源时的安全,必须先让调制器、放大器等小功率的控制电路工作。为此,要保证正确的开机程序。开关稳压器的输入端一般接有小电感、大电容的输入滤波器。在开机瞬间,滤波电容器会流过很大的浪涌电流,这个浪涌电流可以为正常输入电流的数倍。这样大的浪涌电流会使普通电源开关的触点或继电器的触点

56、熔化,并使输入保险丝熔断。另外,浪涌电流也会损害电容器,使之寿命缩短,过早损坏。为此,开机时应该接入一个限流电阻,通过这个限流电阻来对电容器充电。为了不使该限流电阻消耗过多的功率，以致影响开关稳压器的正常工作,而在开机暂态过程结束后，用一个继电器自动短接它,使直流电源直接对开关稳压器供电。这种电路称之谓开关稳压器的“软启动”电路。开关稳压器的控制电路中的逻辑组件或者运算放大器需用辅助电源供电。为此,辅助电源必须先于 开关电路工作。这可用开机程序控制电路来保证。一般的开机程序是:输 入电源的极性鉴别,电压保护开机程 序电路工作辅助电源工作并通过限流电阻 r对开关稳压器的输入电容器c充电 开关稳压

57、器的调制电路工作，短路限流电阻开关稳压器 稳定工作。在开关稳压器中,刚开机时,因为其输出电容容量大,充到额定输出电压值需要一定时间。在这段时间内,取样放大器输入低的输出电压采样,根据系统闭环调节特性将迫使开关三极管的导通时间加长,这样一来,开关三极管就会在这段期间内趋于连续导通,而容易损坏。为此,要求在开机这一段时间内,开关调制电路输出给开关三极管基极的脉宽调制驱动信号，能保证开关三极管由截止逐渐趋于正常的开关状态，故而要加设开机保护以配合软启动。4、过电流保护当出现负载短路、过载或者控制电路失效等意外情况时,会引起流过稳压器中开关三极管的电流过大，使管子功耗增大,发热,若没有过流保护装置,大

58、功率开关三极管就有可能损坏。故而在开关稳压器中过电流保护是常用的。最经济简便的方法是用保险丝。由于晶体管的热容量小,普通保险丝一般不能起到保护作用,常用的是快速熔断保险丝。这种方法具有保护容易的优点，但是,需要根据具体开关三极管的安全工作区要求来选择保险丝的规格。这种过流保护措施的缺点是带来经常更换保险丝的不便。在线性稳压器中常用的限流保护和电流截止保护在开关稳压器中均能应用。但是,根据开关稳压器的特点,这种保护电路的输出不能直接控制开关三极管,而必须使过电流保护的输出转换为脉冲指令,去控制调制器以保护开关三极管。为了实现过电流保护一般均需要用取样电阻串联在电路中,这会影响电源的效率,因此多用

59、于小功率开关稳压器的场合。而在大功率的开关稳压电源中,考虑到功耗，应尽量避免取样电阻的接入。因此,通常将过电流保护转换为过、欠电压保护。5、过电压保护开关稳压器的过电压保护包括输入过电压保护和输出过电压保护。开关稳压器所使用的未稳压直流电源诸如蓄电池和整流器的电压如果过高,使开关稳压器不能正常工作,甚至损坏内部器件,因此,有必要使用输入过电压保护电路。在该电路中，当输入直流电源的电压高于稳压二极管的击穿电压值时，稳压管击穿，有电流流过电阻r， 使晶体管v导通，继电器动作，常闭接点断开，切断输入。其中稳 压管的稳压值vz=esrmaxube。输入 电源的极性保护电路可以跟输入过电压保护结合在一起,构成极性 保护鉴别与过电压保护电路。输出过电压保护在开关稳压电源中是至关重要的