Planar transformer for suppressing common-mode interference by adopting auxiliary winding interference cancellation method

Abstract

The invention relates to a planar transformer for suppressing common-mode interference by adopting an auxiliary winding interference cancellation method. The planar transformer comprises eight layers of PCB windings which respectively comprise a secondary winding N1, a power supply winding N2, an auxiliary winding N3, a primary winding N4, a primary winding N5, an auxiliary winding N6, a power supply winding N7 and a secondary winding N8 from the top layer to the bottom layer. Wherein the secondary windings N1 and N8 are connected in series; the power supply windings N2 and N7 are connected in series; the auxiliary windings N3 and N6 are connected in parallel; the primary windings N4 and N5 are connected in series; and the amplitude of the voltage V3 of the synonym ends of the auxiliary windings N3 and N6 is proportional to the number of turns of the auxiliary windings. Common-mode interference of the primary side and the secondary side of the transformer is counteracted through the reverse jump voltage of the voltage V3 of the synonym ends of the auxiliary windings N3 and N6.

Description

technical field [0001] The invention relates to the field of electronic power, in particular to a planar transformer that adopts an auxiliary winding interference cancellation method to suppress common mode interference. Background technique [0002] With the popularity of fast charging of power supply, small and high frequency has become the main development trend of switching power supply. The traditional winding transformers limit the miniaturization of power supplies due to their large size and weight. The increase in switching frequency can reduce the size and weight of the magnetic components. Planar transformers have been widely used in switching power supplies in recent years due to their small size, high operating frequency, easier realization of a flattened structure, and good heat dissipation and consistency. Among them, the PCB planar transformer uses the printed wire on the printed circuit board as the winding, and the printed wire winding is called the PCB wi...

AI Technical Summary

Problems solved by technology

[0003] As the frequency increases, although the parasitic parameters of the planar transformer are greatly improved compared with the traditional wire-wound transformer, due to the fast switching of the power semiconductor at high frequency, it will cause a large du / dt, di / dt, du / dt, di / dt will produce serious common mode interference through various coupling effects such as parasitic capacitance and stray inductance in the line

Therefore, as the size and frequency increase, the common mode interference of the power supply becomes more and more difficult to deal with.

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