Abstract: The isolated DC/DC converters can easily realize multiple or bipolar output through multi-winding transformers. However, due to the issue of cross-regulation, there is a large deviation between the output port voltages when the load is unbalanced. To solve this problem, a self-balancing isolated DC/DC converter with bipolar output voltage is derived based on flyback converter in this paper. The proposed scheme is simple in structure and low in cost. It can better achieve self-balancing of the port voltage without changing the drive and control circuit design of the traditional flyback converter. Moreover, the proposed converter structure is extensible. The paper first elaborates in detail the derivation process of the proposed converter topology, then analyzes the operating principle, performance characteristics, and the voltage self-balancing mechanism of the converter. Finally, a 150 W experimental prototype is built to verify the correctness and feasibility of the theoretical analysis of the proposed converter.