DC–DC converters are playing a vital in the electric vehicles (EVs) application. In current EVs, a separate DC–DC converter is used to charge both in the low voltage and the high-voltage batteries. These factors have resulted in higher output voltage ripples, higher switching and device conduction losses, all of which can have an impact on EV performance. In addition, the previous mulitport converters have more number of energy storage elements and switching devices for EV application. To address these issues, this article proposes a multiport DC–DC converter charging circuit for EVs. The proposed circuit has a single-input dual-output (SIDO) structure that consists of a positive output boost converter (POBC) with integration of buck converter (POBCIBC). Here, the POBC is used to stepping-up the voltage, while the buck converter is used to step-down the voltage. The POBC is a fundamental topology composed of Cascaded Boost Super Lift Luo Converters. The designed POBCIBC has several advantages such as reduced output voltage ripples, high-voltage transfer gain, proficient efficiency, lower switching and conduction losses, less number of storage components, and a compact structure over the existing multiport converters. The performance of the POBCIBC is tested at different operating conditions by constructing the MATLAB/Simulink and prototype models. The proposed converter has produced different output voltage levels based on their duty cycles variations. The results are presented to show the proficient POBCIBC for the EV application.