Power adapter in the process of use may sometimes be subject to interference from external factors, so how should we solve this interference? 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, you can enhance the design of input/output filtering circuit, improve the performance of active power factor compensation (APFC) circuit, reduce the switching tube and rectifier, renewal diode voltage, current rate of change, the use of a variety of soft-switching circuit topology and control, etc.; on the other hand, to strengthen the shielding effect of the chassis, to improve the chassis leakage of the seams, and a good grounding process.
For external anti-interference capability, such as surge and lightning strike, the lightning protection capability of AC input and DC output ports should be optimized. For lightning strikes, a combination of zinc oxide varistors and gas discharge tubes, etc. can be used to solve the problem. For electrostatic discharge, the use of TVS tubes and the corresponding grounding protection, increase the distance between the small signal circuit and the chassis, etc., or use devices with anti-static interference to solve.
Reduce the internal interference of the power adapter, should start from the following aspects: pay attention to the digital circuit and analog circuit single-point grounding, high-current circuits and small currents, especially current, voltage sampling circuit single-point grounding to reduce the common resistance interference, reduce the impact of the ground loop; wiring, pay attention to the spacing between neighboring wires and the nature of the signal, to avoid crosstalk; to reduce the ground impedance; reduce the high-voltage and high-current lines, especially the transformer The primary side of the transformer and the switching tube, power supply filter capacitor circuit surrounded by the area; reduce the output rectifier circuit and the diode circuit and DC filter circuit surrounded by the area; reduce the leakage inductance of the transformer, the filter capacitor distribution capacitance; the use of resonant frequency of the filter capacitor.
