The interference of the power adapter is a headache for many people, so how to solve the interference of the power adapter? Let's take a look at it today!

According to the factors generated by electromagnetic compatibility, the solution to the electromagnetic compatibility of the power adapter can be started from three aspects:

1. Reduce the interference signal generated by the interference source

2. Cut off the propagation path of interference signals

3. Enhance the anti-interference ability of the interfered object

The external interference caused by the power adapter, such as power line harmonic current, power line conduction interference, electromagnetic field radiation interference, etc., can only be solved by reducing the interference. On the one hand, it can enhance the design of input/output filter circuits, improve the performance of active power factor compensation (APFC) circuits, reduce the voltage and current change rates of switch tubes, rectifier and freewheeling diodes, and adopt various soft switching circuit topology structures and control methods. On the other hand, the shielding effect of the casing is strengthened, the gap leakage of the casing is improved, and good grounding treatment is carried out.

For external anti-interference capabilities, such as surges and lightning strikes, the lightning protection capabilities of AC input and DC output ports should be optimized. Lightning strikes can be solved by a combination of zinc oxide varistors and gas discharge tubes. For electrostatic discharge, TVS tube and corresponding grounding protection are used to increase the distance between the signal circuit and the chassis, or to choose devices with anti-static interference 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 circuits and analog circuits, and the single-point grounding of high-current circuits and low-current circuits, especially current and voltage sampling circuits, so as to reduce the impact of common resistance interference and ground rings; Pay attention to the spacing between adjacent lines and the nature of the signal when wiring to avoid crosstalk; Reduced ground impedance; Reduce the area surrounded by the high-voltage and high-current lines, especially the primary side of the transformer and the switch tube and power filter capacitor circuit; Reduce the area enclosed by the output rectifier circuit, freewheeling diode circuit and DC filter circuit; Reduce the leakage inductance of the transformer and the distributed capacitance of the filter capacitance; Filter capacitors with high resonance frequency are used.

In terms of propagation path, it is appropriate to increase the anti-interference ability of TUS, high-frequency capacitors, ferrite beads and other components with high anti-interference ability to improve the anti-interference ability of small signal circuits; For small signal circuits that are close to the chassis, appropriate insulation and withstand voltage treatment should be added; The radiator of the power device and the electromagnetic shielding layer of the main transformer should be properly grounded; Large-area grounding shield between each control unit; On the frame of the rectifier, the electromagnetic coupling between the rectifiers and the ground wire layout of the whole machine 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 have been briefly understood, I hope you can solve this problem smoothly!