More and more advanced technology has brought more convenience to people's life. More and more electrical equipment began to enter our life. It can be said that switching power supply can be seen everywhere. As we all know, switching power supply is a device that people can see and touch every day. It is mainly used to control the current and turn on and off our equipment. For such a device working in this way, there are too many electrical equipment in daily life, which will interfere with each other in the process of use. What if the internal wifi adapter for desktop switching power supply interferes? How to solve the interference problem of switching power supply?
1、 Generally, the AC Leakage Current of the filter installed on the movable equipment shall be < 1mA. If the power filter is installed in a fixed position and grounded, the AC Leakage Current shall be < 3.5ma, and the specified leakage current of the medical equipment is small. Due to the safety regulations of leakage current, the size of capacitor CY is limited, usually 2.2 ~ 33nF. The type of capacitor is usually ceramic capacitor. Attention should be paid to the resonance effect between capacitor cy and lead inductance during high-frequency operation.
2、 Differential mode interference suppressors usually consist of low-pass filter components. The simplest is to form an input filter circuit by connecting a filter capacitor between two power lines, as shown by capacitor CX1 in Fig. 6. As long as the capacitor is properly selected, the high-frequency interference can be suppressed. The impedance of this capacitor to high-frequency interference is very low, so the high-frequency interference between the two power lines can pass through it. It has high impedance to the power frequency signal, so it has no effect on the transmission of power frequency signal.
3、 The use of shielding layer can reduce the sensitivity of electromagnetic sensitive equipment. The effective way to suppress radiated noise is shielding. Conductive materials can be used to shield the electric field, and materials with high permeability can be used to shield the magnetic field. In order to prevent the leakage of transformer magnetic field and make the primary and secondary coupling of transformer good, closed magnetic rings can be used to form magnetic shielding. For example, the flux leakage of tank core is significantly less than that of e-type. Shielded wires shall be used for switching power cables and power cables to prevent external interference coupling into the circuit.
