Pcb winding transformer

Abstract

The present disclosure discloses a PCB winding transformer. The PCB winding transformer includes a magnetic core and a coil board with a multilayer structure. The coil board includes a primary coil and a secondary coil wound around a magnetic core column of the magnetic core. The secondary coil is located in a first layer and a last layer, and the primary coil is located in intermediate layers. The number of turns of the secondary coil is less than that of the primary coil. At least one via hole for connecting the first layer and the last layer of the secondary coil is disposed in the coil board between an inner side of the primary coil and the magnetic core column.

What is claimed is: 
     
         1 . A PCB winding transformer, comprising:
 a magnetic core and a coil board with a multilayer structure;   wherein the coil board comprises a primary coil and a secondary coil wound around a magnetic core column of the magnetic core, the secondary coil is located in a first layer and a last layer, the primary coil is located in intermediate layers, the number of turns of the secondary coil is less than that of the primary coil; and   wherein at least one via hole for connecting the first layer and the last layer of the secondary coil is disposed in the coil board between an inner side of the primary coil and the magnetic core column.   
     
     
         2 . The PCB winding transformer according to  claim 1 , wherein the secondary coil comprises two turns with flat copper foil, one turn is disposed in the first layer, and the other turn is disposed in the last layer. 
     
     
         3 . The PCB winding transformer according to  claim 1 , further comprising:
 a switching device disposed on the coil board and at least partly overlapped with the secondary coil.   
     
     
         4 . The PCB winding transformer according to  claim 3 , wherein the switching device is a secondary synchronous rectifier disposed on the secondary coil. 
     
     
         5 . The PCB winding transformer according to  claim 3 , wherein the switching device is a secondary rectifier diode disposed on the secondary coil. 
     
     
         6 . The PCB winding transformer according to  claim 1 , wherein the PCB winding transformer is used in a flyback converter.