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How to deal with fault of switch power supply

Writer:www.turnmax-tech.comSource:东莞市腾茂电子有限公司 Date:2016-12-28
Switch power supply circuit is more complex, many fans of the power supply is damaged, in fact, as long as we have a certain understanding, this is not difficult to repair. Here, the principle of switch power supply is the same, and we take the printer as an example of switch power supply, to explain the working principle of switch power supply and fault detection method. Understand the working principle, if you want to study out of switch power supply failure, we need to how it works and which components are easy to damage a understanding. When the city electricity from the input end of the input, the first to reach by the capacitor and inductor component L or filter circuit composed of type A or type A filter to filter out, in order to eliminate the electric surge voltage and interference signal in my city, improve the quality of electric energy. At the same time, the city's input end is connected with a series of fuse, short-circuit failure occurs when the power supply, fuse fusing, avoid the failure of extension. Moreover, most of the switch power input has a varistor. When the voltage is normal, the resistance is infinite, does not affect the circuit work. Once the voltage is too high, pressure sensitive resistance to short circuit, the current through the fuse, fuse fuse, in order to avoid damage caused by high pressure other part.
 
After ac filter through the diode bridge rectifier circuit and high voltage large capacity filter, the output voltage is 300 v high voltage dc. After step-down voltage and simple regulator into the oscillation control circuit oscillation and generate oscillation signals produced by the oscillator amplifier tube, with high frequency transformer, into a low voltage ac voltage and ac low voltage rectifier and filter again after, you can generate a variety of devices used in low voltage direct current (dc).
 
Also the main voltage output voltage sampling also has feedback circuit, voltage feedback oscillation control circuit, once the main voltage due to the load change and voltage drift and oscillation will change the oscillation pulse width control circuit, to ensure the stability of the output voltage. At the same time, when the load short circuit, sampling feedback signal will inform oscillation control circuit, stop the output voltage, avoid damage due to overload the power supply. Fault detection methods have a basic understanding of switch power supply, we want to see the fault detection and maintenance methods. First of all, you should observe the power damage.
 
If insurance tube is damaged, can't eager to change, you must first check the power supply if there is a short circuit phenomenon. Methods: electric hoist table (test) test of power tube insurance deal ends, normal resistance should be in more than a few ohms, such as resistance to zero, then there is a power short circuit phenomenon. In addition, we should also focus on the power of ac filter capacitor is damaged; At the same time, if there is a pressure sensitive resistance, but also should check the resistance. If the above test result is normal, we will detect the four power rectifier diode (test point 2). Normal state, the diode forward resistance for a few K (the multimeter x 1 K piece of test), reverse resistance close to infinity.
 
 

TypeInfo: Industry News

Keywords for the information:Switching power supply manufacturers