BQ24190_15 Datasheet, PDF (18/52 Pages) Texas Instruments – bq2419x I2C Controlled 4.5-A Single Cell USB/Adapter Charger with Narrow VDC Power Path Management and USB OTG

bq24190, bq24192, bq24192I
SLUSAW5B – JANUARY 2012 – REVISED DECEMBER 2014
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9.3.2.3 Supplement Mode
When the system voltage falls below the battery voltage, the BATFET turns on and the BATFET gate is
regulated the gate drive of BATFET so that the minimum BATFET V_DS stays at 30 mV when the current is low.
This prevents oscillation from entering and exiting the supplement mode. As the discharge current increases, the
BATFET gate is regulated with a higher voltage to reduce R_DSON until the BATFET is in full conduction. At this
point onwards, the BATFET V_DS linearly increases with discharge current. Figure 13 shows the V-I curve of the
BATFET gate regulation operation. BATFET turns off to exit supplement mode when the battery is below battery
depletion threshold.
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0
5 10 15 20 25 30 35 40 45 50 55
V(BAT-SYS) (mV)
Figure 13. BATFET V-I Curve
9.3.3 Battery Charging Management
The bq24190, bq24192, bq24192I charges 1-cell Li-Ion battery with up to 4.5A charge current for high capacity
tablet battery. The 12-mΩ BATFET improves charging efficiency and minimizes the voltage drop during
discharging.
9.3.3.1 Autonomous Charging Cycle
With battery charging enabled at POR (REG01[5:4] = 01), the bq24190, bq24192, bq24192I can complete a
charging cycle without host involvement. The device default charging parameters are listed in Table 4.
Table 4. Charging Parameter Default Setting
DEFAULT MODE
Charging voltage
Charging Current
Pre-charge current
Termination current
Temperature profile
Safety timer
bq24190, bq24192
4.208 V
2.048 A
256 mA
256 mA
Hot/Cold
8 hours⁽¹⁾
bq24192I
4.112 V
1.024 A
256 mA
256 mA
Hot/Cold
8 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 TS1 and TS2
• 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 bq24190, bq24192, bq24192I automatically starts another charging cycle.
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