The bq24155 is a compact, flexible, high-efficiency, USB-friendly switch-mode charge management device for single-cell Li-ion and Li-polymer batteries used in a wide range of portable applications. The charge parameters can be programmed through an I²C interface. The bq24155 integrates a synchronous PWM controller, power FETs, input current sensing, high-accuracy current and voltage regulation, and charge termination, into a small WCSP package.

The bq24155 charges the battery in three phases: conditioning, constant current and constant voltage. The input current is automatically limited to the value set by the host. Charge is terminated based on user-selectable minimum current level. A safety timer with reset control provides a safety backup for I²C interface.