【正文】 perature protection Switching regulator and the high level of integration of lightweight small volume, with its unit volume greatly increased the power density, power supply ponents to its work within the requirements of the ambient temperature is also a corresponding increase. Otherwise, the circuit performance will deteriorate, premature ponent failure. Therefore, in highpower switching regulator should be set up overtemperature protection. Relays used to detect 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 overtemperature protection. Temperature relay can be placed in the vicinity of the switching transistor, the general highpower 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 hot thyristor, in the overtemperature protection, played an important role. It can be used as directed circuit temperature. Under the control of photgate thyristor (TT102) characteristics, by RT value to determine the temperature of the device turnon, RT greater the temperature the lower the turnon. 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 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 overtemperature protection, crystal switch the base current by ntype gate control thyristor TT201 thermal bypass, cutoff switch to cut off the collector current to prevent overheating.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 points: 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 overcurrent 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 overvoltage protection is the voltage value. 2) the switching regulator output limit given by the technical indicators within. Work within the required temperature range, the switching regulator39。 load shortcircuit output voltage will also decline. Especially in the reversedphase stepup or stepup switching regulator DC voltage of the protection due to overcurrent protection with closely related and therefore more important. Implementation of Switching Regulators in the termination of the output voltage parators.Normally, there is no parator output, once the voltage drops below the allowable value in the parator on the flip, drive alarm circuit。通常選用幾種保護(hù)方式加以組合,構(gòu)成完善的保護(hù)系統(tǒng)。為了操作方便,便于識(shí)別極性正確與否,在二極管之后接指示燈。為此,開機(jī)時(shí)應(yīng)該接入一個(gè)限流電阻,通過(guò)這個(gè)限流電阻來(lái)對(duì)電容器充電。在這段時(shí)間內(nèi),取樣放大器輸入低的輸出電壓采樣,根據(jù)系統(tǒng)閉環(huán)調(diào)節(jié)特性將迫使開關(guān)三極管的導(dǎo)通時(shí)間加長(zhǎng),這樣一來(lái),開關(guān)三極管就會(huì)在這段期間內(nèi)趨于連續(xù)導(dǎo)通,而容易損壞。在線性穩(wěn)壓器中常用的限流保護(hù)和電流截止保護(hù)在開關(guān)穩(wěn)壓器中均能應(yīng)用。其中穩(wěn) 壓管的穩(wěn)壓值Vz=ESrmax－UBE。它的缺點(diǎn)是動(dòng)作電壓是固定的，溫度系數(shù)大，動(dòng)作點(diǎn)不穩(wěn)定。開關(guān)穩(wěn)壓器內(nèi)部，由于控制電路失?；蛘唛_關(guān)三極管失效會(huì)使輸出電壓下降；負(fù)載發(fā)生短路也會(huì)使輸出電壓下降。采用溫度繼電器來(lái)檢測(cè)電源裝置內(nèi)部的溫度，當(dāng)電源裝置內(nèi)部產(chǎn)生過(guò)熱時(shí)，溫度繼電器就動(dòng)作，使整機(jī)告警電路處于告警狀態(tài)，實(shí)現(xiàn)對(duì)電源的過(guò)熱保護(hù)。倘若配合光電耦合器，就可使整機(jī)告警電路動(dòng)作，保護(hù)開關(guān)穩(wěn)壓器。（2）把開關(guān)穩(wěn)壓器的輸出限制在所給定的技術(shù)指標(biāo)之內(nèi)。保護(hù)措施要視所保護(hù)的部位來(lái)