This paper proposes a novel multi-input and singleoutput DC/DC converter for small unmanned aerial vehicle applications, e.g., multi-rotor drones. A combination of power sources, including a fuel cell, battery, and a super-capacitor, is considered to extend the flight time of such drones. For those multiple sources, the proposed DC/DC power converter consists of two functional parts, which are the charging and discharging operation for the battery and super-capacitor and the regulation of the output voltage. And two operation modes, according to the primary power sources, are also discussed. Therefore, the proposed converter can achieve high power density and low cost because the proposed converter can have small counts of components with the same functions of the conventional converter. The feasibility of the proposed converter was verified with a 400 W prototype (14.8 V/27.03 A), and the experimental results validated the theoretical analysis and showed the effectiveness of the proposed converter for the small unmanned aerial vehicle applications.