bq24296
bq24297
SLUSBP6A –SEPTEMBER 2013–REVISED OCTOBER 2013
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Table 5. Charging Parameter Default Setting
DEFAULT MODE
Charging Voltage
Charging Current
Pre-charge Current
Termination Current
Temperature Profile
Safety Timer
bq24296 / bq24297
4.208 V
2.048A
256 mA
256 mA
Hot/Cold
12 hours(1)
(1) See section Charging Safety Timer for more information.
A new charge cycle starts when the following conditions are valid:
•
•
•
•
•
Converter starts
Battery charging is enabled by I2C register bit (REG01[5:4]) = 01 and CE is low
No thermistor fault on TS
No safety timer fault
BATFET is not forced to turn off (REG07[5])
The charger device automatically terminates the charging cycle when the charging current is below termination
threshold and charge voltage is above recharge threshold. When a full battery voltage is discharged below
recharge threshold (REG04[0]), the device automatically starts another charging cycle.After the charge done,
either toggle /CE pin or REG01[5:4] will initiate a new charging cycle.
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.
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 6. Charging Current Setting
VBAT
CHARGING CURRENT
REG DEFAULT SETTING
REG08[5:4]
VBAT < VSHORT
(Typical 2V)
100mA
–
01
VSHORT ≤ VBAT < VBATLOWV
(Typical 2V ≤ VBAT < 3V)
REG03[7:4]
REG02[7:2]
256mA
01
10
VBAT ≥ VBATLOWV
2048mA
(Typical VBAT ≥ 3V)
28
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