BQ24618 Datasheet, PDF (15/36 Pages) Texas Instruments – Stand-Alone USB-Friendly Synchronous Switch-Mode Li-Ion or Li-Polymer Battery Charger

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OPERATIONAL FLOWCHART
POR
Turn on
BATDRV FET
VCC > SRN
SLEEP MODE
No
Indicate SLEEP
Yes
Enable VREF LDO &
Chip Bias
30ms delay
Turn off BATFET
Turn on ACFET
bq24618
SLUSA55 – OCTOBER 2010
Indicate battery
absent
No
Battery
present?
Initiate battery
detect algorithm
Yes
See Enabling and Disabling
Charge Section
Conditions met
for charge?
No
Yes
VFB < VLOWV
Yes
Indicate NOT
CHARGING,
Suspend timers
No
Conditions met
for charge?
Start 30 minute
precharge timer
Yes
Regulate
precharge current
Indicate Charge-
In-Progress
No
VFB < VLOWV Yes
Precharge
timer expired?
No
Start Fastcharge
timer
Indicate NOT
CHARGING,
Suspend timers
Regulate
fastcharge current
No
Conditions met
Yes
for charge?
Indicate Charge-
In-Progress
Turn off charge,
Enable IDISCHG for 1
second
Yes
Indicate Charge In
Progress
No
VFB > VRECH
&
ICHG < ITERM
No
Fastcharge
Timer Expired?
No
Yes
Yes
FAULT
Enable IFAULT
Indicate FAULT
VFB < VRECH
Charge Complete
No
Indicate DONE
No VFB > VRECH
Yes
Battery Removed
Yes
Indicate BATTERY
ABSENT
Figure 16. Operational Flowchart
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