ShenZhen Yinghuiyuan Electronics Co.,Ltd
During the normal operation of the Power Adapter, once the output voltage noise occurs, it will not only interfere with the system work, but also bury hidden dangers for the safe operation. Then what are the methods to improve the voltage noise? Let's follow the manufacturers together to understand it!
The first method that can effectively improve the output voltage noise of desktop Power Adapters is that YHY engineers can use chip three-terminal capacitors combined with ordinary electrolytic capacitors at the output of high-power power adapters to improve the high-frequency characteristics of the filter. Before we look at the specific mode of operation of this method, we need to first understand why the adapter has noise voltage spikes. Without any additional measures, the output end of the adapter usually contains a large peak noise voltage, which is caused by the imperfect characteristics of electrolytic capacitors at high frequencies. Because the electrolytic capacitor can be equivalent by series of capacitor, resistor and inductor at high frequency, the capacitor's bypass effect on noise is not obvious at high frequency. Due to the presence of resistance and inductance, the noise voltage is reflected in the output of the switching power adapter instead.
Method one: the output electrolytic capacitor is disassembled into several, that is, a large-capacity electrolytic capacitor is replaced by several small-capacity electrolytic capacitors in parallel. Although this suggestion can not inhibit the generation of noise voltage fundamentally, the peak-peak value of noise voltage produced by the new method is smaller than the original one.
Method two: is next to the electrolytic capacitor in parallel with a small capacity of high frequency ceramic capacitor, the use of high frequency capacitor at high frequency reflected in the low capacitance, so that the output noise voltage is greatly attenuated, of course, the ceramic capacitor on the printed circuit board should also maintain a relatively short wiring length, to maintain as small as possible line impedance.
The second way to improve the output voltage noise of the power adapter is to use a high performance surface mount filter to improve the peak noise. The internal circuit of the mount filter can be equivalent to a π type filter line, and a high performance filter is mounted on the output string of the switching power adapter. Compared with the original output noise voltage peak value, the peak noise voltage is almost displayed as a straight line on the oscilloscope in the test, which indicates that the noise of the output voltage has been significantly suppressed. The function of surface-mounted high performance filter in this circuit is explained.
Privacy statement: Your privacy is very important to Us. Our company promises not to disclose your personal information to any external company with out your explicit permission.
Fill in more information so that we can get in touch with you faster
Privacy statement: Your privacy is very important to Us. Our company promises not to disclose your personal information to any external company with out your explicit permission.