Operating a DC-DC converter on a chip that includes: micro-power-switching phases and magnetic material, each phase including: a high-side and low-side switch with control inputs for activating the switch, and an output node; where: the output node of each phase extrudes through the magnetic material to form, in each phase, a toroidal inductor with a single loop coil, and to form, for the plurality of phases, a directly coupled inductor; the output node of each micro-power-switching phase is coupled to a filter and a load; each high-side switch is configured, when activated, to couple a voltage source to the phase's single loop coil; and the low-side switch of each phase is configured, when activated, to couple the phase's single loop coil to a ground voltage and the switches are alternatively activated where no two switches of any phase are activated at the same time.