The BQ25171-Q1 is an automotive rated, 800-mA linear charger for 1-cell and 2-cell Li-Ion, Li-Polymer, and LiFePO4, in addition to 1-cell up to 6-cell NiMH battery applications. The device has a single power output that charges the battery. The system load can be placed in parallel with the battery, as long as the average system load does not prevent the battery from charging fully within the safety timer duration. When the system load is placed in parallel with the battery, the charge current is shared between the system and the battery.
The device has three phases for charging a Li-Ion battery: precharge to recover a fully discharged battery, fast-charge constant current to supply the bulk of the charge, and voltage regulation to reach full capacity.
The device charges a NiMH in constant current mode only, and terminates the charge cycle when the programmable timer expires or the battery voltage exceeds the VOUT_OVP threshold. In all charge phases, an internal control loop monitors the IC junction temperature and reduces the charge current if an internal temperature threshold, TREG, is exceeded.