Summary: 1 Introduction See the PDF document for details (click on the PDF file to download) Toothbrush Sanitizer Holder,Multi Function Toothbrush Sterilizer,Uv Light Toothbrush Holder,Toothbrush Sterilizer Holder Ningbo HanCheng(HC) Electronic Co.,Ltd , https://www.hcwires.com
The evaluation of the quality index of the switching power supply should be based on safety and reliability as the first principle [1, 2, 3]. Under the condition that the electrical technical indicators meet the requirements of normal use, in order to make the power supply work safely and reliably under harsh environment and sudden failure, it is necessary to design various protection circuits, such as anti-surge soft start, anti-overvoltage and undervoltage. , overheating, overcurrent, short circuit, lack of equal protection circuit. At the same time, in the same switching power supply circuit, the design of various protection circuits and the problems that should be paid attention to should also be paid enough attention.
2 anti-surge soft start circuit
The input circuit of the switching power supply mostly uses a capacitor filter type rectifying circuit. When the incoming line power is turned on, the initial voltage on the capacitor is zero, and the capacitor charging moment will form a large surge current, especially the high-power switching power supply. Larger filter capacitors allow surge currents of up to 100A. Such a large surge current at the moment of power-on, often causes the input fuse to blow or the contact of the closing switch to burn out, and the rectifier bridge is over-current damaged; the lighter will also make the air switch not close. 4]. All of the above phenomena will cause the switching power supply to fail to work properly. For this reason, almost all switching power supplies are provided with a soft start circuit for preventing inrush current to ensure normal and reliable operation of the power supply. Anti-surge soft start circuits usually have two categories: thyristor protection method and relay protection method.