Power transformer and circuit board module

A circuit board module, comprising:

• a circuit board, comprising a first surface and a second surface opposite to each other;
• a plurality of rectifier transistors, disposed on the first surface of the circuit board, wherein each of the rectifier transistors comprises a drain;
• a power transformer, disposed on the second surface of the circuit board, and comprising:
• at least one primary side conductive piece;
• at least one secondary side conductive piece, stacked to the at least one primary side conductive piece along an axis;
• a first conductive strip pin, extending from the at least one secondary side conductive piece, and bent and extending along the axis, wherein the first conductive strip pin is conductive to a portion of the drains of the rectifier transistors;
• a second conductive strip pin, extending from the at least one secondary side conductive piece, and bent and extending along the axis, wherein the second conductive strip pin is conductive to another portion of the drains of the rectifier transistors;
• and
• an iron core set, coupled to the at least one primary side conductive piece and the at least one secondary side conductive piece.