Why does the power adapter cause noise interference?

Power adapters are very common in daily life, and of course there are some common problems, such as noise interference in the adapter. Shenzhen Waweis Technology Co., Ltd. is a professional Power Supply adapter manufacturer.

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Let's analyze the power supply for you.

Why does the adapter have noise interference:

1. Suppress the EMI generated by the power supply itself;
2. Prevent external electromagnetic noise from interfering with the work of the load of the power supply;
3. Suppresses EMI generated by other equipment and propagated through the power supply.

4. Prevent external electromagnetic noise from interfering with the work of the control circuit of the power supply equipment itself;

In addition to the drive circuit, the Switching Power Supply also has a protection circuit, a program circuit, an input and output level detection circuit, etc., and the circuit is quite complex. These circuits are mainly composed of dedicated or general-purpose power supply integrated circuits. An effective way to prevent these circuits from malfunctioning due to external noise is to use noise filters.

There are two types of propagating noise: common-mode noise and normal-mode noise. Common mode noise is the current flowing into the ground, and normal mode noise is the current flowing between the wires. When taking noise countermeasures, the common mode noise is mainly considered. However, in the low frequency range, a large proportion of noise is transmitted in the normal state. Therefore, an appropriate noise filter must be selected according to the noise components.

Best Regards,

Mandy Huang