The MCP1632 offers an asynchronous, low-side MOSFET driver, which supports a variety of different topologies. Boost is ideal for lower-power, Step-up converters. Note: There is no disconnect (protection) between the input/output. SEPIC is a Single-Ended-Primary-Inductor-Converter, offers buck, boost, and buck-boost capability. Finally, Flyback Transformer allows significant increases in voltage (due to the turns ratio of the transformer), making this good for higher-output-voltage application needs.