Devices and methods for DC-to-DC conversion. The device includes a first transformer having a first winding at a primary side and a second winding at a secondary side. The device also includes a second transformer having a third winding at a primary side and a fourth winding at a secondary side. The device includes a controller configured to control a first current in the first winding of the first transformer and a second current in the third winding of the second transformer to flow in a first pattern, and to control the first current and the second current to flow in a second pattern.