Balun transformer using a drum-shaped core
A balun transformer includes: a drum-shaped core having a core unit and a pair of flanges arranged on both sides of the core unit; a plurality of terminal electrodes arranged on the flanges; a primary winding wound around the core unit, both ends of the primary winding being connected to the terminal electrodes; and a secondary winding wound around the core unit, both ends and a center tap of the secondary winding being connected to the terminal electrodes, wherein the secondary winding includes a first wire extending from one end to the center tap, and a second wire extending from the other end to the center tap, and the first wire and the second wire are wound around the core unit so as to extend along each other.
1. A balun transformer comprising:
a drum-shaped core having a core unit and a pair of flanges arranged on both sides of the core unit;
a plurality of terminal electrodes arranged on the flanges;
a primary winding wound around the core unit, both ends of the primary winding being connected to the terminal electrodes such that one end of the primary winding is connected to the terminal electrode arranged on one flange, and the other end of the primary winding is connected to the terminal electrode arranged on the other flange; and
a secondary winding wound around the core unit, both ends and a center tap of the secondary winding being connected to the terminal electrodes,
wherein the secondary winding includes a first wire extending from one end to the center tap, and a second wire extending from the other end to the center tap, and the first wire and the second wire are wound around the core unit so as to extend along each other, and
wherein the plurality of terminal electrodes include first to sixth terminal electrodes,
the first to third terminal electrodes are arranged in this order as viewed from one direction on the one flange, the fourth to sixth terminal electrodes are arranged in this order as viewed from the one direction on the other flange,
one end of the primary winding is connected to the first terminal electrode,
the other end of the primary winding is connected to the fourth terminal electrode,
one end of the secondary winding is connected to the third terminal electrode,
the other end of the secondary winding is connected to the sixth terminal electrode,
a part of the center tap of the secondary winding belonging to the first wire is connected to the fifth terminal electrode, and
another part of the center tap of the secondary winding belonging to the second wire is connected to the second terminal electrode.
2. The balun transformer as claimed in claim 1 , wherein
the plurality of terminal electrodes further include seventh and eighth terminal electrodes,
the primary winding includes a third wire extending from the one end to a relay point and a fourth wire extending from the other end to the relay point,
the seventh terminal electrode is located between the first and second terminal electrodes on the one flange,
the eighth terminal electrode is located between the fourth and fifth terminal electrodes on the other flange,
a part of the relay point belonging to the third wire is connected to the eighth terminal electrode,
another part of the relay point belonging to the fourth wire is connected to the seventh terminal electrode, and
the third and fourth wires are wound around the core unit so as to extend along each other.
3. The balun transformer as claimed in claim 1 , wherein
the plurality of terminal electrodes include first to fourth terminal electrodes,
the first and second terminal electrodes are arranged on the one flange,
the third and fourth terminal electrodes are arranged on the other flange,
one end of the primary winding is connected to the first terminal electrode,
the other end of the primary winding is connected to the second terminal electrode,
the one end of the secondary winding is connected to the third terminal electrode,
the other end of the secondary winding is connected to the fourth terminal electrode, and
the center tap of the secondary winding is connected to the second terminal electrode.
4. The balun transformer as claimed in claim 3 , wherein the primary winding is wound on an outer circumferential side of the core unit, and the secondary winding is wound on an inner circumferential side of the core unit.