BQ27741-G1_14 Datasheet, PDF (14/39 Pages) Texas Instruments – Single Cell Li-Ion Battery Fuel Gauge with Integrated Protection

bq27741-G1
SLUSBF2 – JULY 2013
www.ti.com
OCC Fault
CHG FET off
DSG FET on
Fuel Gauge on
LDO on
(V_SRP – V_SRN) > V_OCC
Fault recovery:
Charger removed
Normal
Fuel Gauge in
Normal, SLEEP,
FULLSLEEP Modes
CHG FET on
DSG FET on
Fuel Gauge on
LDO is on
> ^VUVPREL
V ^VPWR
< ^VUVP
V ^VPWR
UVP Fault
(POR State)
CHG FET on
DSG FET off
Fuel Gauge on
LDO is on
FW(ROM) turns
FETs off briefly
POR
(Force UVP set)
(V_SRN – V_SRP) > V_OCD
OR
(V_SRN – V_SRP) > V_SCD
V_VPWR > V_OVP
Charger removed
Shutdown bit
cleared
Low Voltage Charging
CHG FET control shorted to
PACKP pin
DSG FET off
Protection off
Fuel Gauge off
LDO is off
OCD/SCD Fault
CHG FET on
DSG FET off
Fuel Gauge on
LDO on
Fault recovery:
Charger removed
load removed
Shutdown Bit
set
V_VPWR < V_OVPREL
AND
Charger attached
AND
Fault recovery:
V_VPWR>V_LVDET
Charger removed
Analog Shutdown
Shutdown Wait
CHG FET off
OVP Fault
CHG FET off
DSG FET on
Fuel Gauge on
CHG FET off
DSG FET off
Fuel Gauge on ^{Charger removed}
DSG FET off
Fuel Gauge off
LDO is off
LDO on
LDO is on
Virtual Shutdown
Figure 3. Operating Modes
Virtual Shutdown Mode
In this mode, the fuel gauge is not functional and only certain portions of analog circuitry are running to allow
device wakeup from shutdown and low voltage charging.
Analog Shutdown Mode
In this mode, the fuel gauge is not functional. Once the charger is connected, the fuel gauge determines if low
voltage charging is allowed and then transitions to low voltage charging.
Low Voltage Charging Mode
In this mode, the fuel gauge closes CHG FET by shorting the gate to PACKP pin. Low voltage charging
continues until the cell voltage (V_VPWR) rises above the POR threshold.
Undervoltage Fault Mode
In this mode, the voltage on VPWR pin is below V_UVP and the charger is connected. As soon as the charger
disconnects, the fuel gauge transitions into Analog Shutdown Mode to save power.
The fuel gauge can enter this mode from Low Voltage Charging Mode when the battery pack is being charged
from a deeply discharged state or from Normal Mode when the battery pack is being discharged below the
allowed voltage.
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