电子气专业毕业外文翻译---直流开关稳压电源的保护技术(编辑修改稿)

电子气专业毕业外文翻译---直流开关稳压电源的保护技术(编辑修改稿)内容摘要：

damage to the switch transistor, the output potential may be increased immediately to the importation of nonregulated DC power supply voltage value, causing great loss instantaneous. Commonly used method is shortcircuit protection thyristor. The simplest overvoltage protection circuit. When the output voltage is too high, the regulator tube breakdown triggered thyristor turnon, the output shortcircuit, resulting in overcurrent 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 ~ 10μs. 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 overvoltage startup the same but has different values, difficult to debug. Esc a sudden increase in output voltage, transistors V1, V2 conduction, the thyristor conduction. Reference voltage Vz by type. undervoltage 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 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 normal, ZD breakdown voltage regulator tube, transistors V conduction, the relay action, contact pullin, powerswitching regulator. When the input below the minimum allowable voltage value, the regulator tube ZD barrier, V cutoff, contact Kaihop, switching regulator can not work. Internal switching regulator, as the control switch transistor circuit disorders or failure will decrease the output voltage。 load shortcircuit output voltage will also decline. 外文翻译 5 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。 also fed back to the switching regulator control circuit, so that switching transistor cutoff or cut off the input power. overtemperature 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。