This paper describes a prototype design of a maximum power peak tracking controller for a solar cell array embedded on a wing of UAV. Solar cells are used to both cover part of the UAV power consumption and (at suitable conditions) to charge onboard battery. As the UAV changes its position and attitude to the sun relatively fast, the lighting conditions on the solar cells change rapidly. Thus, it is necessary to implement a fast maximum power peak tracking controller to ensure maximum efficiency of the system. The proposed design is based on commercial off-the-shelf components. The implemented DC/DC converter, which represents the core of the regulator, is a combination of a step‑ up and a step‑ down converter. Weight, dimensions end overall efficiency were the key optimization parameters of the design.