A magnetic integrated device, comprising a magnetic core, a first transformer winding, and a second transformer winding, wherein a window is disposed in the magnetic core, and the first transformer winding and the second transformer winding respectively pass through the window and are wound around the magnetic core; wherein the magnetic core comprises a first piece and a second piece disposed opposite to each other and enclosing the window; the first transformer winding and the second transformer winding are separated and each wound around both the first piece and the second piece, the first piece being a I-shaped piece and the second piece being a U-shape piece comprising a groove in the second piece; wherein a first part of the first transformer winding and a first part of the second transformer winding are both wounded around the second piece in the groove of the second piece, a second part of the first transformer winding and a second part of the second transformer winding are both wounded around the first piece, a first winding axis of the first part of the first transformer winding and a second winding axis of the first part of the second transformer winding are aligned, and a third winding axis of the second part of the first transformer winding and a fourth winding axis of the second part of the second transformer winding are aligned; wherein the magnetic integrated device further comprises a magnetic pillar that is located in the window and located between the first transformer winding and the second transformer winding; and wherein the magnetic pillar is located on a side of first piece or on a side of the second piece and a first side of the magnetic pillar comes in contact with the magnetic core on the side on which it is located, and there is a gap between the opposite side to the first side of the magnetic pillar and the magnetic core. a window is disposed in the magnetic core, and the first transformer winding and the second transformer winding respectively pass through the window and are wound around the magnetic core; wherein the magnetic core comprises a first piece and a second piece disposed opposite to each other and enclosing the window; the first transformer winding and the second transformer winding are separated and each wound around both the first piece and the second piece, the first piece being a I-shaped piece and the second piece being a U-shape piece comprising a groove in the second piece; wherein a first part of the first transformer winding and a first part of the second transformer winding are both wounded around the second piece in the groove of the second piece, a second part of the first transformer winding and a second part of the second transformer winding are both wounded around the first piece, a first winding axis of the first part of the first transformer winding and a second winding axis of the first part of the second transformer winding are aligned, and a third winding axis of the second part of the first transformer winding and a fourth winding axis of the second part of the second transformer winding are aligned; wherein the magnetic integrated device further comprises a magnetic pillar that is located in the window and located between the first transformer winding and the second transformer winding; and wherein the magnetic pillar is located on a side of first piece or on a side of the second piece and a first side of the magnetic pillar comes in contact with the magnetic core on the side on which it is located, and there is a gap between the opposite side to the first side of the magnetic pillar and the magnetic core.