SC DC-DC converters have wide applications. Previous works proposed multiple topologies for a high voltage conversion ratio scenario, such as Dickson, Cockcroft-Walton, Series-Parallel, Ladder, Fibonacci and Divider. They have their own features, fitting different applications. However, it is unclear how these topologies are generated, what the main differences are between them, and what the advantages and disadvantages are. Therefore, this paper starts from the transformer model of the SC converters, analyzing the difference among them. Then, it is demonstrated how the SC converters evolve from the model to the real circuitries, where multiple intuitive understanding can be obtained.