Power supply circuitry is always limited by cost, PCB area, height and by the desire to reduce complexity. The majority of systems today are mixed-signal, and in all but the simplest cases, the various analog and digital circuits need several different supply voltages to operate. One way to add additional outputs to a power supply without adding additional control ICs is to replace the standard inductor of a buck regulator with a multi-winding inductor. One winding is energized by the buck regulator, and there are many ways to create a second output by rectifying and filtering the voltage induced in the second winding. Buck regulators are found in nearly every power supply architecture, and the multi-winding inductor can be custom-wound to provide various turns ratios and even multiple outputs, but in the interest of controlling both complexity and cost, this application note will focus on off-the-shelf, 1:1 coupled inductors.