BQ25601 Datasheet, PDF (25/60 Pages) Texas Instruments – I2C Controlled 3-A, Single-Cell Battery Charger for High Input Voltage and Narrow Voltage DC (NVDC) Power Path Management

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Voltage
9V
3.6V
3.4V
3.2V
3.18V
VBUS
SYS
BAT
bq25601
SLUSCK5 – MARCH 2017
Current
4A
3.2A
2.8A
ISYS
ICHG
1.2A
IIN
1.0A
0.5A
-0.6A
DPM
DPM
Supplement
Figure 16. DPM Response
8.4.7.10 Supplement Mode
When the system voltage falls 180 mV (VBAT > VSYSMin) or 45 mV (VBAT < VSYSMin) below the battery
voltage, the BATFET turns on and the BATFET gate is regulated the gate drive of BATFET so that the minimum
BATFET VDS 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 RDSON until
the BATFET is in full conduction. At this point onwards, the BATFET VDS linearly increases with discharge
current. Figure 17 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
3.5
3
2.5
2
1.5
1
0.5
0
0
5 10 15 20 25 30 35 40 45 50 55
V(BAT-SYS) (mV)
D001
Plot1
Figure 17. BAFET V-I Curve
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