Electronic circuit device

An electronic circuit device, comprising:

• a board that is formed of at least one insulating base;
• a patterned conductor that is formed on the at least one insulating base;
• a transformer that is provided at the board, the transformer having:
• a magnetic core;
• a primary winding member, the primary winding member being configured with:
• a primary winding that is an integrated part of the patterned conductor and that is provided at the board;
• and
• a primary side element that is incorporated in and electrically connected to the primary winding, wherein the primary side element is directly electrically connected to the primary winding without an intervening connecting pattern portion provided therebetween;
• and
• a secondary winding member, the secondary winding member being configured with:
• a secondary winding that is an integrated part of the patterned conductor and that is provided at the board;
• and
• a secondary side element that is incorporated in and electrically connected to the secondary winding, wherein the secondary side element is directly electrically connected to the secondary winding without an intervening connecting pattern portion provided therebetween,
• wherein each of the primary winding and the secondary winding is wound around the magnetic core, and the primary winding and the secondary winding are magnetically coupled with each other via the magnetic core;
• and
• a first current path that is an integrated part of the patterned conductor between an input terminal of the electronic circuit device and the primary winding member, the input terminal being provided on the board, wherein the first current path is located so as to perpendicularly abut the primary winding member so that a magnetic flux generated by an electric current flowing in the first current path does not cross the primary winding member.