Printed circuit board of planar transformer and manufacturing method thereof

A PCB of a planar transformer, comprising a PCB substrate, wherein the PCB further comprises a double-sided winding part formed on double sides of the PCB substrate by colloid injection molding and integrated with the PCB substrate;

• the PCB substrate is provided with a through hole;
• the double-sided winding part is of a symmetric structure on the double sides of the PCB substrate, a via hole consistent with the through hole is formed in the center of the double-sided winding part, and the via hole is aligned to the through hole to form a magnetic core hole allowing a magnetic core to pass through;
• the circumference of the via hole is raised to form wire blocking parts;
• and
• a wire passing groove is formed in the wall of the magnetic core hole, wherein the wire passing groove allows a metal conducting wire to pass through to be planarly wound from inside to outside on double sides of the double-sided winding part at the same time so as to form two coils in series located on the double sides of the PCB substrate.