BQ24195 Datasheet, PDF (22/41 Pages) Texas Instruments – I2C Controlled 2.5A / 4.5A Single Cell USB/Adapter Charger With 5.1V at 1A / 5.1V at 2.1A Synchronous Boost Operation

bq24195
bq24195L
SLUSB97 – OCTOBER 2012
Voltage
9V
3.6V
3.4V
3.2V
3.18V
VBUS
SYS
BAT
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Current
4A
3.2A
2.8A
ISYS
ICHG
1.2A
IIN
1.0A
0.5A
-0.6A
DPM
DPM
Supplement
Figure 17. DPM Response
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 30mV 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 18 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 18. BATFET V-I Curve
Battery Charging Management
The bq24195L, bq24195 charges 1-cell Li-Ion battery with up to 2.5A/4.5A charge current for high capacity tablet
battery. The 12mΩ BATFET improves charging efficiency and minimizes the voltage drop during discharging.
Autonomous Charging Cycle
With battery charging enabled at POR (REG01[5:4]=01), the bq24195L, bq24195 can complete a charging cycle
without host involvement. The device default charging parameters are listed in .
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