This battery charger is designed for a 40V, 320W notebook PC, featuring the BQ25770G quasi-dual-phase buck-boost battery charge controller. This reference design delivers 320W with 98% peak efficiency, and spreads out the heat across two parallel half bridges and inductors. Gallium nitride (GaN) field effect transistors (FETs) are chosen as the high-side FETs for high efficiency, and silicon FETs are chosen as the low-side FETs for low cost. This hybrid-FET reference design is cost-effective and highly-efficient for high-power multicell battery chargers.