Coupled inductor
A coupled inductor has two pillars that are aligned in a vertical direction, wherein a first coil and a second coil are respectively wound around one of the two pillars, respectively, wherein the bottom surface of winding turns of the first coil and the bottom surface of winding turns of the second coil are separated by a gap, wherein a magnetic material is disposed in the gap and a straight line that is enclosed by each of the first coil and the second coil passes through the two pillars.
1 . A coupled inductor, comprising:
a magnetic T-core, comprising a magnetic plate and a pillar, wherein a first opening, a second opening, a third opening and a fourth opening are formed on a first corner, a second corner, a third corner and a fourth corner of the magnetic plate, respectively, wherein the first corner and the second corner are on a first side of the magnetic plate, and the third corner and the fourth corner are on a second side of the magnetic plate, wherein the first side and the second side are two opposite sides of the magnetic plate;
a first coil, comprising at least one first winding turn of a first conductive wire;
a second coil, comprising at least one second winding turn of a second conductive wire; and
a magnetic material disposed between the first coil and the second coil, wherein the at least one first winding turn of the first conductive wire and the at least one second winding turn of the second conductive wire are respectively wound around the pillar, wherein a vertical line passes through the pillar with each of the at least one first winding turn and each of the at least one second winding turn being respectively wound around the vertical line; and wherein each of a first terminal part and a second terminal part of the first conductive wire respectively extends toward the first opening and the second opening of the magnetic plate, and each of a first terminal part and a second terminal part of the second conductive wire respectively extends toward the third opening and the fourth opening of the magnetic plate, wherein each of the first terminal part and the second terminal part of the first conductive wire is respectively bent onto a bottom surface of the magnetic plate via the first opening and the second opening of the magnetic plate; and wherein each of the first terminal part and the second terminal part of the second conductive wire is respectively bent onto the bottom surface of the magnetic plate via the third opening and the fourth opening of the magnetic plate, wherein the pillar comprises a first pillar and a second pillar spaced from the first coil by a gap, the first coil surrounds the first pillar, the second coil surrounds the second pillar, and the magnetic material is disposed in the gap, wherein a permeability of the first pillar and the second pillar is in a range from 25 to 45, wherein the magnetic material comprises a first magnetic powder and each of the first pillar and the second pillar comprises a second magnetic powder, and an average particle size of the first magnetic powder is less than an average particle size of the second magnetic powder.
2 . The coupled inductor according to claim 1 , wherein the first coil and the second coil are inversed coupled and the coefficient of coupling (K) of the first coil and the second coil has a negative value.
3 . The coupled inductor according to claim 2 , wherein K is in the range: −0.4 to −0.8.
4 . The coupled inductor according to claim 1 , further comprising a magnetic body encapsulating the at least one first winding turn, the at least one second winding turn, and the pillar.
5 . The coupled inductor according to claim 1 , wherein the magnetic plate is integrally formed with the pillar.
6 . The coupled inductor according to claim 1 , wherein the magnetic material is a magnetic sheet or a magnetic glue.
7 . The coupled inductor according to claim 1 , wherein the magnetic material surrounds the pillar and contacts a bottom surface of the first coil and a top surface of the second coil.
8 . The coupled inductor according to claim 1 , wherein the pillar further comprises a middle pillar disposed between the first pillar and the second pillar, the first terminal part of the first conductive wire is disposed adjacent the middle pillar, and the second terminal part of the first conductive wire is disposed adjacent the magnetic plate.
9 . The coupled inductor according to claim 1 , wherein the first terminal part and the second terminal part of the first conductive wire are parallel extended on the magnetic plate in a first direction, and the first terminal part and the second terminal part of the second conductive wire are parallel extended on the magnetic plate in a second direction that is opposite to the first direction.