DC Switching Power Supply Protection Technology
Posted:2006-2-26 10:57:00 visit:665 chine Version Related News
Abstract: The DC switching power supply protection system is propod to protect the system design principles and machine protection measures, analysis of switching power supply in the range of protected characteristics and design method, introduced veral practical protection of circuit.
发电机十大品牌Keywords: switching power supply protection circuit system design
1 Introduction 请说普通话
刑事上诉状范本
DC switching regulator ud in the price of more expensive high-power switching devices, the control circuit is also more complex, In addition, the load switching regulators are generally ud a large number of highly integrated devices installed electronic systems. Transistors and integrated device tolerance of electricity, less heat shocks. Thus switching regulator should take into consideration the protection of voltage regulators and load their o
wn safety. Many different types of protection circuits introduced here polarity protection, program protection, over-current protection, over-voltage protection, under voltage protection and thermal protection circuits. Several protection methods are usually chon to be combined to form a comprehensive protection system.
2 Polarity Protection
DC switching regulator's input are generally not regulated DC power supply. Due to operational errors or unforeen circumstances will be the wrong polarity, switching power supply will be damaged. Polarity protection purpos, is to make the switching regulator only when the correct polarity is not regulated to DC power supply when connected to work. The u of a single wizard-pass device can achieve the power supply polarity protection. As the diode D to flow through the switching regulator's input total current, so this circuit applied in a low-power switching regulators on the more appropriate. Power in the larger occasion, put the polarity protection circuit as a program to protect a link, eliminating the need for high power required for polarity protection diode
s, power consumption will be reduced. For convenient operation, easy to identify the polarity right or wrong冬至未至。
3 process protections 派遣女王>明目张胆
Switching power supply circuit more complicated, basically can be divided into a low-power control ction and power switch part. Belong to high-power switching transistor, in order to protect the switching transistor is turned on or off the power when the curity must make the modulators, amplifiers and other small power control circuit. To this end, to ensure that the correct boot process. Switching regulator's input generally received a small inductance and large capacitance of the input filter. In the boot an instant, filter capacitor will flow through the large surge current, the inrush current can be veral times the normal input current. Make such a large surge current ordinary power switch contact or relay contact melting, and to enter the fu fu. In addition, the surge current can also damage the capacitor, so that shortened life expectancy, premature damage. To this end, the boot should be access to a current-limiting resistor, through whi
ch current-limiting resistor to charge the capacitor. In order not to make the current-limiting resistors consume excessive power, thereby affecting the normal operation of switching regulators, and in the boot after the end of the transient process, with an automatic relay shorted it, so that DC power directly to the switching regulator power supply。
Switching regulator control circuit of the logic components or operational amplifiers need to u auxiliary power supply. For this reason, auxiliary power must be on the switch circuit. This can be the boot process control circuitry to be guaranteed. Normal boot process are: identification of the polarity of input power, voltage protection - the boot process circuit - auxiliary power supply through current-limiting resistor R of the switching regulator's input capacitor C charge - the modulation switching regulator circuit, short-circuit current-limiting resistor - switching regulator stability.
高中英语作文范文10篇 In the switching regulator, by just getting on its machines, becau of its large output capacitance, charge to the rated output voltage take some time. During this time, the sam
pling amplifier input and low output voltage sampling, according to the system characteristics of the clod-loop regulation will force the switch transistor conduction time longer, this way, the switching transistor during this period will tend to continuous conduction, and easily damaged. To this end, requests the boot this period of time, switching modulation circuit output to the switching transistor ba of the pul-width modulated drive signals, which would ensure switching transistor deadline to gradually normalize the switching state and therefore I need to create boot protection to meet the soft - Start.
4over-current protection
三国杀卡牌游戏 When the load short-circuit, overload control circuit failure or unexpected situations such as when, it will cau flow through the regulator in the switching transistor current is too large, so that incread power tube, fever, if there is no over-current protection devices, high power switching transistor there may be damaged. Guer in the switching regulator in the over-current protection is commonly ud. The most economical way is to
u simple fu. As the transistors heat capacity is small, generally can not play a regular fu protection, commonly ud is fast fu fu. This approach has the advantage of the protection easy, but it needs specific switching transistor safe operating area requirements to lect the fu specifications. Such over-current protection measures, disadvantage is the inconvenience caud frequent replacement of fu.
