Realization of high power isolated dc-dc converters is largely dependent on managing converter parasitics and losses. In this paper, four different dc/dc converter topologies are compared in terms of their losses. The topologies include hard switched half bridge, switched snubber half bridge, zero voltage switching phase shifted full bridge and loss limited (semi soft switched) full bridge converters. These topologies have been designed to obtain 350 V 300 A dc output from a 650 V dc input at 20 kHz switching frequency. Design results and loss evaluations are presented.