With computers and servers becoming increasingly widespread, a growing amount of public attention has been focused on improving the efficiency of the server power supply. In this paper, the high-voltage bus converter in the present architecture of the server power supplies is replaced by the multiple output converter to improve the efficiency as there are a variety of loads. Aimed at improving the efficiency, several kinds of multiple output converters are compared and an input-series output-parallel multiple output converter composed of a DCX and a dc-dc converter is put forward. The operation principle of the converter is analyzed, the proper circuit topology is chosen and the control strategy is proposed. The equivalent circuit of the chosen DCX circuit topology is analyzed, based on which, the parameters of the converter are designed according to a white gold server power supply. Finally, a 500 W prototype is built based on the Freescale singlechip MC56F8257, and the experimental waveforms and the tested efficiency curve are given to verify the feasibility of this input-series outputparallel multiple output converter.