Power device

A power device, comprising:

• a mainboard, comprising a first side and a third side opposite each other along a first direction, and a second side and a fourth side opposite each other along a second direction, wherein the first direction is perpendicular to the second direction;
• and
• a power conversion module, comprising a primary-side circuit board and a secondary-side module;
• wherein the secondary-side module comprises a secondary-side circuit board, the primary-side circuit board and the secondary-side circuit board are both disposed on the mainboard, such that the primary-side circuit board, the mainboard and the secondary-side circuit board are electrically connected, the primary-side circuit board and the secondary-side circuit board are spatially separated, and the secondary-side circuit board is disposed adjacent to the third side along the first direction, the primary-side circuit board is disposed away from the third side, the secondary-side module further comprises a secondary-side element and a first magnetic core element, wherein the secondary-side element and the first magnetic core element are disposed on the secondary-side circuit board along a third direction perpendicular to the first direction and the second direction, the secondary-side element and the first magnetic core element are adjacent to each other, the secondary-side element is disposed adjacent to the mainboard, the first magnetic core element is disposed away from the mainboard, and the first magnetic core element is disposed on the secondary-side circuit board to form a transformer.