BQ24298_15 Datasheet, PDF (20/51 Pages) Texas Instruments – bq24298 I2C Controlled 3A Single Cell USB Charger With Narrow VDC Power Path Management and Adjustable Voltage USB OTG

bq24298
SLUSC59 – APRIL 2015
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The STAT output indicates the charging status of charging (LOW), charging complete or charge disable (HIGH)
or charging fault (Blinking). The status register REG08[5:4] indicates the different charging phases: 00-charging
disable, 01-precharge, 10-fast charge (constant current) and constant voltage mode, 11-charging done. Once a
charging cycle is complete, an INT is asserted to notify the host.
The host can always control the charging operation and optimize the charging parameters by writing to the
registers through I²C.
8.3.3.2 Battery Charging Profile
The device charges the battery in three phases: preconditioning, constant current and constant voltage. At the
beginning of a charging cycle, the device checks the battery voltage and applies current.
Table 4. Charging Current Setting
VBAT
V_BAT < V_SHORT
(Typical 2 V)
V_SHORT ≤ V_BAT < V_BATLOWV
(Typical 2 V ≤ V_BAT < 3 V)
V_BAT ≥ V_BATLOWV
(Typical V_BAT ≥ 3 V)
CHARGING CURRENT
100 mA
REG03[7:4]
REG02[7:2]
REG DEFAULT SETTING
–
128 mA
2048 mA
REG08[5:4]
01
01
10
If the charger device is in DPM regulation or thermal regulation during charging, the actual charging current will
be less than the programmed value. In this case, termination is temporarily disabled and the charging safety
timer is counted at half the clock rate.
Regulation Voltage
(3.5V – 4.4V)
Fast Charge Current
(500mA-3008mA)
VBAT_LOWV (2.8V/3V)
Battery Voltage
Charge Current
VBAT_SHORT (2V)
IPRECHARGE (128mA-2048mA)
ITERMINATION (128mA-2048mA)
IBATSHORT (100mA)
Trickle Charge Pre-charge
Fast Charge and Voltage Regulation
Figure 14. Battery Charging Profile
Safety Timer
Expiration
8.3.3.3 Thermistor Qualification
The charger device provides a single thermistor input for battery temperature monitor.
8.3.3.3.1 Cold/Hot Temperature Window
The device continuously monitors battery temperature by measuring the voltage between the TS pin and ground,
typically determined by a negative temperature coefficient thermistor and an external voltage divider. The device
compares this voltage against its internal thresholds to determine if charge or boost is allowed.
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