In a multi-phase power converter, efficiency is increased and ripple reduced while maintaining transient response and dynamic performance improved by electrically coupling secondary windings of transformers or provided for inductors of respective phases such that current to a load is induced in each phase by current in another phase. Magnetic coupling can also be provided between phases using a multi-aperture core of a configuration which minimizes primary winding length and copper losses. Efficiency at light load is enhanced by controlling current in the series connection of secondary windings in either binary or analog fashion.