Multi-output LLC Resonant Converters With Symmetrical Auxiliary Output Structures

With limitation of lowest load, multi-output LLC resonant topologies with asymmetrical structures on the main output and auxiliary outputs, wherein, whose auxiliary outputs adopt symmetrical structure, dedicating to multi-output power supply systems which is applied as auxiliary supply of the driving chip for the up and down bridges, are presented in this paper. According to output power level, different configuration of secondary output end can be flexibly adapted. Consequently, the presented topology is a favorable candidate for such application as whose outputs are not symmetrical, i.e. compared with auxiliary outputs, power level of main output is comparatively higher. In addition, all switches of the very topology operate under the condition of ZVS and therefore it is applicable to such occasion as high frequency, high power density. Asymmetrical operating principle between the main output and auxiliary outputs are specified, besides, ZVS operation is analyzed in details, moreover key parameter design considerations are presented. Finally, the analysis above is verified by experimental results