How to solve the interference of the power adapter?

According to the factors of EMC, the EMC of power adapter can be solved from three aspects:

1, reduce the interference signal generated by the interference source

2. Cut off the transmission path of interference signals

3, enhance the anti-interference ability of the interfered body

External interference caused by the power adapter, such as harmonic current of the power line, power line conduction interference, and electromagnetic radiation interference, can only be solved by reducing the interference. On the one hand, it can enhance the design of input/output filter circuit, improve the performance of active power factor compensation (APFC) circuit, reduce the voltage and current change rate of switching tube and rectifier diode, and adopt a variety of soft switching circuit complement structure and control mode. On the other hand, strengthen the shielding effect of the casing, improve the gap leakage of the casing, and a good grounding treatment.

To the external anti-jamming ability, such as surge, lightning strikes, should optimize the AC input and DC output port lightning protection ability. The combination of zinc oxide varistor and gas discharge tube can be used to solve the lightning strike. For electrostatic discharge, TVS tube and the corresponding grounding protection, increase the distance between the small signal circuit and the housing, or use anti-static interference devices to solve the problem. To reduce the internal interference of the power adapter, we should start from the following aspects: pay attention to the single point grounding of digital circuit and analog circuit, the single point grounding of large current circuit and small current, especially current and voltage sampling circuit, in order to reduce the common resistance interference and reduce the influence of the ground loop; When wiring, pay attention to the spacing between adjacent lines and the nature of the signal to avoid crosstalk; Reduce ground impedance; Reduce the area surrounded by the high voltage and large current lines, especially the original side of the transformer and the switching tube, the power filter capacitor circuit; Reduce the area surrounded by the output rectifier circuit, the continuing diode circuit and the DC filter circuit; Reduce the leakage inductance and filter capacitance of the transformer; Filter capacitors with high resonant frequency are used.

In terms of transmission path, TUS with high anti-interference ability, high frequency capacitor, ferrite magnetic beads and other components should be appropriately added to improve the anti-interference ability of small signal circuit; Small signal circuit close to the housing, should add appropriate insulation and pressure treatment; The radiator of the power device, the electromagnetic shielding layer of the main transformer should be properly grounded; Large area grounding between each control unit with floor shield; In the frame of the rectifier, the electromagnetic coupling between the rectifiers and the whole machine ground layout should be considered to improve the stability of the internal work of the power adapter.

How to solve the interference of the power adapter must be a simple understanding of you, I hope you can solve this problem smoothly when you encounter!