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-current protection。 However, the instantaneous maximum value should be converted to the average current。 At rated output current and output voltage conditions, theswitch of the dynamic load line does not exceed a safe working area DC maximum input voltage, input over-voltage 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 regulator's output voltage, the lower limit of the output is off, due to the voltage value of voltage protection。 Over-current protection can be based 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 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 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。 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 affected 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 least 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 normal operation of switching power supplies and high-efficiency and high reliability。

Essay two： intelligent   Switching Power

 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 equipment 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 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 transformer 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 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 equipment, 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。