Recently, a customer asked us if the noise of the inductor they used before was relatively loud and asked if we could solve it. Today, let's talk about this issue.

From the perspective of the inductors currently on the market, except for the multilayer inductors and integrated inductors, the occurrence of noise from other inductors is basically impossible to eliminate fundamentally. It's just that for some noise levels, we can use various methods to reduce and lower the noise to solve the customer's problem. The ultimate goal is to make it inaudible.

To solve the noise generated by the inductor, you must know what causes the noise so that you can solve it in a targeted way.

The noise of the inductor is mainly caused by the vibration of the core such as high flux, ferrite, and iron powder core, while the vibration of the core such as high flux, ferrite, and iron powder core can be considered from two aspects: material and structure.

The continuous noise of ferrite inductors is mainly caused by the following reasons:

1. Magnetic expansion and magnetic distortion, as well as the vibration of the core caused by magnetic attraction.

2. Winding vibration caused by electromagnetic force.

3. The magnetic permeability and Bs parameters of the magnetic material cause the product characteristics to be too poor.

4. The operating frequency of the inductor is close to the cutoff frequency, and resonance occurs during operation.

5. The operating current is too large, reaching or exceeding 1/3 of the rated current.

6. The superimposed current characteristics are too poor.

To reduce noise, you can use the inductor body noise source and set up noise walls.

1. Change the structure of the magnetic core and the tightness of the winding product to control the sound emitted by the magnetic core body. The main improvement measures are as follows:

①. Use a high-density magnetic core material with small distortion

②. In the inductor manufacturing process, use varnish to fix the winding coil.

③. Add a dispensing process during the production process to tighten the magnetic core and magnetic ring.

2. Change the product characteristics to adjust the self-resonance frequency of the product to avoid the sound generated by the self-resonance of the product.

①. Adjust the inductance value of the inductor to change the resonant frequency.

②. Avoid the resonance response of the core vibration of the ferrite inductor and the basic frequency.

3. Improve the current characteristics of the product

①. Improve the gap between the core joints, reduce and disperse the magnetic gap joints.

②. Avoid leakage magnetic flux from direct or indirect contact with the core.

③. Change the inductance value of the inductor.

The above methods can be used in different ways according to different inductors, and can reduce noise by several db to varying degrees. If you want to significantly reduce the noise, you must add a soundproof wall or a material with lower vibration transmission performance to the shell of the inductor to isolate the path of noise transmission.