Windings and Formation Methods for Transformers

A method for forming a winding, comprising:

• providing a conductive wire;
• winding, along a step direction, the conductive wire around a winding core to form a first solenoid;
• extending the conductive wire along a direction parallel to the step direction to form a connection section on the first solenoid;
• and
• winding, along the step direction, the conductive wire around the first solenoid and the connection section to form a second solenoid.

A transformer, comprising:

• a winding core;
• a primary winding, comprising:
• a first winding layer comprising a first solenoid wound around the winding core along a step direction;
• a connection section on the first winding layer, substantially parallel to the step direction;
• and
• a second winding layer comprising a second solenoid wound around the first winding layer and the connection section along the step direction;
• and
• a secondary winding, comprising a secondary solenoid wound around the second solenoid.