Inductor device

An inductor device, comprising:

• a carrier board having a plurality of through holes;
• a plurality of parallel walls protruding upward from the carrier board;
• a hollow magnetic core;
• and
• a winding assembly having a plurality of conductive structures and a plurality of U-shaped conductors, and the conductive structures are disposed below the hollow magnetic core, each U-shaped conductor is disposed between immediately-adjacent two of the plurality of parallel walls, the conductive structures are arranged along a segment of the hollow magnetic core, and the U-shaped conductors are arranged around and beyond the segment of the hollow magnetic core, wherein two ends of at least one of the U-shaped conductors are inserted into corresponding ones of the through holes respectively in contact with two of the conductive structures such that the U-shaped conductors and the conductive structures are electrically connected to each other and collectively continuously surround the segment of the hollow magnetic core, wherein the conductive structures are U-shaped, and each of the conductive structures has two ends inserted into the carrier board, the plurality of conductive structures and the plurality of U-shaped conductors are on the same side of the carrier board.