BQ24253

The bq24250, bq24251, and bq24253 are highly integrated single-cell Li-Ion battery chargers and system power-path management devices targeted for space-limited, portable applications with high-capacity batteries. The single-cell charger has a single input that operates from either a USB port or an AC wall adapter for a versatile solution.

The power-path management feature allows the bq24250, bq24251, and bq24253 to power the system from a high-efficiency DC-DC converter while simultaneously and independently charging the battery. The charger monitors the battery current at all times and reduces the charge current when the system load requires current above the input current limit. This reduced charge current allows for proper charge termination and enables the system to run with a defective or absent battery pack. Additionally, this reduced charge current enables instant system turnon even with a totally discharged battery or no battery. The architecture of the power-path management also permits the battery to supplement the system current requirements when the adapter cannot deliver the peak system currents. This supplementation of current requirements enables the use of a smaller adapter.

The battery is charged in four phases: trickle charge, precharge, constant current, and constant voltage. In all charge phases, an internal control loop monitors the IC junction temperature and reduces the charge current if the internal temperature threshold is exceeded. Additionally, a voltage-based, JEITA compatible battery pack thermistor monitoring input (TS) that monitors battery temperature for safe charging is included.