A multiple phase buck converter or boost converter, or buck-boost converter has an inductor in each phase. A magnetic core with a unique woven topology provides inverse coupling between the inductors. The inductors can comprise straight conductors since the magnetic core has the woven topology wrapped around each inductor. The inductors have a reduced electrical resistance since they are straight and do not loop around the magnetic core. The reduced electrical resistance increases energy efficiency and improves transient response of the circuit. The magnetic core can comprise top and bottom portions that are magnetically connected. The inductors can comprise straight circuit board traces and the circuit board can have holes to accommodate the magnetic core.