Coil device and switching power supply apparatus using the same

摘要

A coil device having a core having an intermediate leg and at least a pair of external legs arranged at equal intervals from the intermediate leg; a first printed coil provided on a first substrate which has an intermediate hole and a pair of external holes respectively inserted in the intermediate leg and the pair of external legs of the core, the first printed coil being wound around the intermediate hole; and a second printed coil provided on a second substrate which has an intermediate hole and a pair of external holes respectively inserted in the intermediate leg and the pair of external legs of the core, the second printed coil including a pair of external printed coils which are connected in series and are respectively wound around the pair of the external holes with the same number of turns but in opposite directions.