The global energy landscape is rapidly transitioning toward 100% renewable sources, with large-scale photovoltaic (PV) installations playing a central role in achieving net-zero carbon emission targets. However, the intermittent and environmentdependent nature of PV generation necessitates efficient power electronic interfaces for optimal energy harvesting and reliable grid integration. In this context, this paper introduces a new single-switch DC-DC buck-boost converter with a wide conversion-ratio range is proposed for photovoltaic (PV) applications. Furthermore, the detailed operating principle, steady-state analysis, and design considerations of the topology are presented. The proposed topology is validated through MATLAB/Simulink simulations at 1 kW power level. The converter exhibits strong performance in both boost and buck operating modes, achieving theoretical efficiencies of 95.15% and 96.87%, respectively. Furthermore, the proposed design ensures continuous input current and maintains a common ground between the input and output ports, which makes it highly suitable for modern photovoltaic energy-conversion systems