The device charges the battery in five phases: trickle charge, pre-charge, constant current, constant voltage, and top-off trickle charging (optional). At the beginning of a charging cycle, the device checks the battery voltage and regulates current/voltage accordingly.

If the charger is in DPM regulation or thermal regulation during charging, the actual charging current is less than the programmed value. In this case, termination is temporarily disabled and the charging safety timer is counted at half the clock rate, as explained in Charging Safety Timer.

The V_{BAT_SHORTZ} is the battery voltage threshold for the transition from trickle charge to pre-charge, which is fixed value 2.2V. During the trickle charge to pre-charge transition, the charger regulates the battery voltage to 2.5V/cell typical for t_{BAT_SHORTZ} duration. V_{BAT_LOWV} is the battery voltage threshold for the transition from pre-charge to fast charge. It is defined as a ratio of battery voltage regulation limit (VREG).

During SYSMIN regulation with BATFET LDO operation, the charge current is limited to 2 A maximum, regardless of the charge current register setting being set higher than 2 A, in order to protect the BATFET. The BATFET LDO operation can be disabled by setting DIS_LDO = 1. In this condition, the pre-charge current and fast charge current are both regulated by the buck converter PWM current regulation loop. The SYS is no longer regulated to VSYSMIN when the LDO mode is disabled at the low battery voltage condition. When in trickle charge, setting DIS_LDO = 1 does not affect I_{BAT_SHORT} or VSYSMIN operation.

Figure 8-10 Battery Charging Profile