The present invention relates to a transformer. In the transformer, secondary winding sections are placed in both sides of a primary winding section, all terminals of the secondary winding sections are used as output terminals, and an input terminal is placed in the opposite side to the output terminals. Therefore, a return wire in the high-voltage output side does not need to be provided, and a sufficient insulation separation distance is secured in the relation with a printed circuit board, which makes it easy to implement a circuit. Further, improved efficiency is obtained over a conventional transformer, there is a significant reduction in cost, and products using the transformer can be small in size. The transformer includes a bobbin composed of one primary winding section having one input terminal and one ground terminal and 2n (n: positive number) secondary winding sections, each secondary winding section having two output terminals; a primary coil wound around the primary winding section; secondary coils wound around the 2n secondary winding sections; and a pair of cores that are respectively inserted into an insertion hole formed inside the bobbin.
1. A transformer comprising:
a bobbin composed of one primary winding section having one input terminal and one ground terminal and 2n (n: positive number) secondary winding sections, each secondary winding section having two output terminals;
a primary coil wound around the primary winding section;
secondary coils wound around the 2n secondary winding sections; and
a pair of cores that are respectively inserted into an insertion hole formed inside the bobbin.
2. The transformer according to claim 1 ,
wherein the primary winding section is placed in the center of the bobbin, and the n secondary winding sections are respectively placed in both sides of the primary winding section.
3. The transformer according to claim 1 ,
wherein, on the primary and secondary winding sections, a plurality of insulating slits are formed.
4. The transformer according to claim 1 ,
wherein, when the primary coil is wound, the winding starts from the input terminal of the primary winding section and is completed at the ground terminal thereof.
5. The transformer according to claim 1 ,
wherein, when the secondary coil is wound, the winding starts from one output terminal of the secondary winding section and is completed at the other output terminal thereof.
6. The transformer according to claim 1 ,
wherein the input terminal and ground terminal of the primary winding section are placed in the same direction.
7. The transformer according to claim 1 ,
wherein the output terminals of the secondary winding section are placed in the same direction.
8. The transformer according to claim 1 ,
wherein the input terminal of the primary winding section is placed in the opposite side to the output terminals of the secondary winding sections.
9. The transformer according to claim 1 ,
wherein two output terminals placed in the outermost sides from the center of the bobbin are placed on both side surfaces of the bobbin.
10. The transformer according to claim 1 ,
wherein the core is an E-shaped core.
11. The transformer according to claim 1 ,
wherein the core is formed by a combination of a U-shaped core forming an outer magnetic path and an I-shaped core forming an inner magnetic path.