This paper proposes a DC-DC step-up converter with a high voltage gain for solar and fuel cell systems. This converter combines a Zeta converter with one basic cell of the coated circuit and a Quadratic-Boost converter by a high-frequency transformer. The outputs of these two converters are connected in a series to boost the output voltage of the combined DC-DC converter. The proposed converter not only can achieve higher voltage gain but also acquire lower voltage stress on the semiconductor devices. Therefore, the devices with lower conduction resistances. Moreover, the circuit is made so that the outputs of each part of the converter keep the same properties as those of the converter that came before the combination, ensuring that each converter's known benefits are maintained. The proposed topology has one switch, which keeps the number of components low. The simulation of 240-watt, input voltage 30-volt, and 100kHz using the PLECS program is obtained to confirm the theoretical analysis of the proposed converter.