JAJSLW9B May 2020 – January 2023 BQ25798
PRODUCTION DATA
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.
VBAT | CHARGING CURRENT | REGISTER DEFAULT SETTING | CHRG_STAT |
---|---|---|---|
< VBAT_SHORT | IBAT_SHORT | 100 mA (fixed value) | 001 |
VBAT_SHORTZ to VBAT_LOWV | IPRECHG | 120 mA | 010 |
> VBAT_LOWV | ICHG | 1 A | 011 |
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 Section 9.3.9.4.
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. It is not recommended to set the battery regulation voltage lower than the SYSMIN regulation voltage. The BATFET LDO operation can be disabled by setting DIS_LDO = 1. In this state, charge current is regulated according to Table 9-10 and SYS voltage is V(BAT) plus the IR drop through the BATFET, regardless of battery voltage. No VSYSMIN is maintained. Note that, when in trickle charge, setting DIS_LDO = 1 does not affect IBAT_SHORT.
VBAT_SHORTZ is the battery voltage threshold for transition from trickle charge to precharge, which is fixed at 2.25V typical. During the trickle charge to precharge transition, the charger regulates the battery voltage to 2.5V/cell typical for tBAT_SHORTZ duration. VBAT_LOWV is the battery voltage threshold for the transition from precharge to fast charge. It is defined as a ratio of battery voltage regulation limit (VREG).