Selecting the desired MOSFET fit for Buck-Boost for higher efficiency in power supply and battery charging section discussed in this app note from Alpha & Omega Semiconductors. Link here (PDF)
The wide adoption of USB Type-C PD makes the notebook PC charger move to four MOSFET buck-boost charger topology to allow for wide range input voltage (5-20V). After a suitable controller is selected, the specified Power MOSFETs in buck-boost charger are essential for achieving higher efficiency and high-power density design.
In this application note, we will only discuss the USB power delivery specification for an adapter supplying 5A/100W and expect the reader to understand the basic operation of buck-boost topology. It is critical to select suitable MOSFETs regarding efficiency, thermal, and space limitation, to meet the system-level requirements. 30V MOSFETs can be used for input voltage below 20V.
Based on given wide input voltages, output voltages, and current, the designer must understand the tradeoff among the different loss mechanisms in the MOSFET. These MOSFET losses include: switching loss, conduction loss, and reverse recovery loss. Losses are minimized by selecting the best MOSFETs from its electrical characteristics.