This paper presents a comparison of Isolated (Fly-back) and non-Isolated (Buck) multiple input-single output (MISO) DC-DC converters for the integration of low-power hydroelectric and photovoltaic voltage sources. The analysis of DC-DC converters is based on pulsed voltage source cells (PVSC). The modeling of both converter types is detailed through their mathematical models and electrical simulations using Matlab/Simulink and PSIM. The comparison focuses on the sizing parameters, non-ideal output characteristics and efficiency. Results show that the output voltage of the MISO Buck converter exhibits a linear dependence on the duty cycles control signal and has slightly higher efficiency than the Flyback converter.