Transformer and electronic apparatus including the same

An electronic device comprising:

• a board having a mounting region;
• a transformer comprising:
• a bobbin part comprising an outer bobbin including a first bobbin body having a predetermined length, a first through hole formed in a longitudinal direction of the first bobbin body and a first winding region formed around an outer circumferential surface of the first bobbin body, and an inner bobbin including a second bobbin body having a predetermined length, a second through hole formed in a longitudinal direction of the second bobbin body and a second winding region formed around an outer circumferential surface of the second bobbin body, the inner bobbin being inserted into the first through hole of the outer bobbin;
• a core part comprising a first core and a second core, wherein portions of the first and second cores are electromagnetically coupled to each other through the second through hole of the inner bobbin;
• and
• a winding portion comprising a primary winding wound around the first winding region of the outer bobbin, and at least one secondary metallic plates wound around the second winding region of the inner bobbin, the at least one secondary metallic plate having at least one extension portion extending to the outside;
• and
• a heat dissipation body formed on the board, connected to the extension portion of the at least one secondary metallic plate, and dissipating heat generated from the at least one secondary metallic plate.