In this study, a global fast terminal sliding-mode control (GFTSMC), which offers a faster convergence performance than its counterparts is constructed for managing the state variables of the DC-DC buck converters. For the first time in this study, the GFTSMC was designed for power electronics circuits based on hysteresis modulation (HM). The HM technique's variable switching frequency problem is overcome by reusing the GFTSMC structure, which enables the hysteresis band to be changed adaptively, and a fixed switching frequency is obtained. The proposed control scheme uses only one sensor for regulating the output voltage and controlling the switching frequency. Thus, an extremely economical and robust system, which is minimally affected by the negative aspects originating from the sensors, is obtained. Effectiveness of the proposed controller is validated with experimental studies. The experimental results shows that the output voltage and switching frequency are successfully controlled with good dynamic and steady state response. Finally, to validate the experimental feasibility of this paper, a comparison of the proposed method and four existing studies with different control schemes is presented.