Planar transformer, power converter and circuit board

Abstract

The invention provides a planar transformer, a power converter and a circuit board. The planar transformer comprises a secondary coil layer, a first shielding layer, a second shielding layer and a primary coil layer which are located on a PCB, wherein the secondary coil layer comprises at least part of a secondary coil, and the secondary coil is provided with a secondary static point end; the first shielding layer comprises N1 circles of first shielding coil sections, and each first shielding coil section comprises a first shielding static point end and a first shielding free end; the second shielding layer comprises a second shielding coil section of N2 circles, and the second shielding coil section comprises a second shielding static point end and a second shielding free end; the windingdirection of the first shielding coil section is the same as the winding direction of the secondary coil, and the winding direction of the first shielding coil section is opposite to the winding direction of the second shielding coil section. The N1 circles of first shielding coil sections and the N2 circles of second shielding coil sections of the shielding coil jointly play a role in restraining common-mode current, and finally the sum of the common-mode current is very small through cooperative cooperation.

Description

technical field [0001] The invention relates to the field of planar transformers, in particular to planar transformers, power converters and circuit boards. Background technique [0002] The common-mode current of the transformer has a great influence on EMI. It is necessary to reduce the common-mode current caused by the primary coil as much as possible. Usually, in a traditional transformer, the common-mode current is adjusted by adjusting the number of turns of the transformer shielding winding to reduce EMI. interference from common mode noise. [0003] Planar transformers are small in size and are more and more widely used in switching power supplies. However, it is often difficult to obtain a good common-mode current suppression effect in existing planar transformers. Contents of the invention [0004] The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a planar transformer and a power converter to reduce the common-mo...

AI Technical Summary

Problems solved by technology

However, the existing planar transformers are often difficult to obtain a good common-mode current suppression effect

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