Kumar, A.Kalpana, R.2026-02-0620252025 IEEE Energy Conversion Congress and Exposition Asia: Shaping a Greener Future with Power Electronics, ECCE-Asia 2025, 2025, Vol., , p. -https://doi.org/10.1109/ECCE-Asia63110.2025.11112402https://idr.nitk.ac.in/handle/123456789/28615In this paper, A A 3.3kW, 600V DC input, 400V DC output, 250kHz Gallium nitride (GaN) based Dual Active Bridge (DAB) DC-DC Converter for EV on-board charger (OBC) is proposed. Typically, OBC consists of two stages, AC-DC and isolated DC-DC converter. An optimized design of isolated DC-DC converter with high switching frequency is proposed. In order to achieve high power density and high efficiency, DAB converter with GaN high electron mobility transistors (GaN-HEMT) as switch and Planar transformer are selected for converter design. Design of Planar transformer-based DAB Converter design are discussed in detail. Core selections and PCB based winding design of Planar Transformer are also discussed. The OBC is designed and evaluated in PLECS software. The performance of proposed GaN based DC-DC converter and SiC-DAB are analyzed and their losses are compared and presented in PLECS Software. © 2025 IEEE.DC-DC ConverterDual Active Bridge (DAB)EV On-Board ChargerPlanar MagneticsWide Band Gap Devices (WBG)