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
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.