In order to reduce the loss and improve the efficiency and working range of the DC/DC converter, a high efficiency hybrid full bridge DC/DC converter is proposed. It is composed of a phase-shifted full-bridge series resonant converter and an active clamped boost converter with a voltage doubler circuit, and uses a hybrid control scheme with a simple circuit structure. In the normal input range, the proposed converter works as a phase-shifted full-bridge series resonant converter, which improves the conversion efficiency by applying soft switching on all switches and rectifier diodes and reducing the conduction loss. When the input is lower than the normal input range, the converter operates as an active clamp boost converter, which increases the operating range. Due to the hybrid operation, the proposed converter operates with a larger phase shift value than a conventional converter at the normal input range. Therefore, the proposed converter can provide high power conversion efficiency over a wide operating range. A 1 kW prototype is built to verify the theoretical analysis and effectiveness of the proposed converter. This work is supported by National Science Foundation for Distinguished Young Scholars (No. 51325704).