bq24040 & bq24050 Battery Charger ICs Texas Instruments bq24040 and bq24050 Battery Charger ICs are highly integrated devices targeted at space-limited portable applications. The TI bq24040, bq24050, and bq24055 operate from a USB port or AC adapter and feature a high input voltage range with input overvoltage protection to support low-cost unregulated adapters. These TI battery charger ICs have a single power output that charges the battery. A system load can be placed in parallel with the battery as long as the average system load does not keep the battery from charging fully during the 10-hour safety timer. The bq24040 and bq24050 charges the battery in three phases: conditioning, constant current, and constant voltage. An internal control loop monitors the IC junction temperature in all three phases and reduces the charge current if an internal temperature threshold is exceeded.