The oscillation's decompression peak is also communicated to the output end during the energy transfer process, creating noise. We typically employ RC, RCD, and other absorption circuits, and the absorption capacitors frequently make use of high-voltage ceramic capacitors, to tackle this issue.
The attractive force between the two parts of the magnetic core due to relative motion to move it, compressing the medium separating them, as well as the impact that causes the surfaces of the two magnetic cores to contact, and they respond, are some of the mechanisms in the transformer that cause noise to be produced. There are fissures in the middle legs of the magnetic core as well as the movement of the magnetic flux excitation will cause the two to collide or scratch.
Cheap ceramic capacitors also contain non-linear insulating materials that frequently have a high concentration of barium titanate, which at normal operating temperatures generates a piezoelectric effect. Because of this, these parts will produce more noise than capacitors with linear insulating components. To solve capacitance issues, we can swap out the high-voltage ceramic capacitors used in the absorption circuit for polyester film capacitors that have a negligible electrostrictive effect. This will essentially eliminate the noise produced by capacitance.
The final factor is the noise brought on by the printed circuit board's signal interference. This issue will be resolved by adding absorption circuits at both ends of the FET DS during the design phase in order to lessen spikes, which will significantly lower the output noise of the power module.
