How to Generate Auxiliary Supplies from a Positive Buck DC-DC Converter

Abstract: Many applications require a low-power supply in addition to the main supply. For reasons of cost, inventory management, or electromagnetic compatibility (EMC), a separate converter may not be appropriate. Consequently, another means of providing extra power rails from the main supply is needed. This application note shows how to use a step-down IC converter's switching action to derive one or more outputs, isolated or non-isolated, quasi-regulated or unregulated.