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BQ25071-Q1: Precharge Level

Part Number: BQ25071-Q1
Other Parts Discussed in Thread: BQ25071


I have two questions on the LifePo4 precharge current :

-What is the real voltage value (min / typ / max) considered in the BQ25071 for the precharge current for LiFePo4?

-What is the time out value ( min / typ / max) considered in BQ25071?


Can you confirm that the _CHG indicator will go high impedance if the time out has elapsed and the battery voltage is still under the pre-charge threshold of 0.7V (+/-0.2V)?

Thanks and regards, 


  • Hello Mohamed,

    Vlowv (pre-charge to fast-charge threshold) is 0.5 V min, 0.7 V typ, 0.9 V max

    The bq25071 does not have safety timers.
    In devices that do, however, charge terminates and the CHG pin goes high impedance if the time is exceeded.
  • Hello Diana,

    What do you mean by BQ25071 has no safety timer ?

    Is it that during charge (Pre charge and/or fast charge) nd in case of Voltage is still remaining between0V5 min/0V7max/0V9max during charging, the BQ25071 will continue to charge until an external application will decide to stop the charging ?

    How can it be handled ?

    Thanks & regards,
  • Hello Mohamed

    Without timers, the charger stays in precharge for unlimited time until the precharge threshold (typ 0.7 V) is reached. The typical charging cycle is followed, without time limits, unless some stopping condition occurs such as battery removal or if the junction temperature of the device reaches shutdown temperature.