BQ24901_13 Datasheet, PDF (15/18 Pages) Texas Instruments – OFFLNE APPLICATIONS

bq24901
APPLICATION INFORMATION
SLUS527 – DECEMBER 2002
Charge Timers
The bq24901 provides two charge timers to protect the battery during pre-charge and charge phases. The first
timer, T30min, is reset at the beginning of a new charge cycle and initiated in the pre-charge phase. During
pre-charge, if the timer expires before the battery rises above the V_LOWV threshold, a fault condition is
annunciated. Power-on reset or battery replacement clears the fault.
The second timer, T5hr, is reset at the beginning of a new charge cycle and is initiated at the beginning of the
charge phase. A fault condition is annunciated if the battery current fails to reach charge termination current
detect threshold, I_TERM, during charge. Power-on reset or battery replacement clears the fault.
Charge Status Display
The open-drain STAT1 and STAT2 outputs indicate various charger operations as shown in the Table 3.
Table 3. Charge Termination Adjustment
CHARGE STATE
Battery absent
STAT1
OFF(1)
STAT2
OFF
Charge-in-progress
ON
OFF
Charge done
OFF
ON
Charge suspend (temperature)
OFF
OFF
Timer fault
OFF
OFF
(1) OFF means the open-drain output transistor on the STATx pin
is in an off state.
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