This circuit is a buck-boost charger used to charge battery in mobile devices. The circuit features the ISL9237 device from Intersil, which is capable of providing buck mode, buck-boost mode and boost mode for 1 to 3 cell lithium ion batteries. This single chip takes the place of a two-chip solution used in other designs that requires separate buck and boost chips. Using this eliminates a charger chip and an inductor, which reduces BOM cost up to 40%. Read more