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BQ77905: BQ7790518: with OV cutoff as 4.25V and recovery time of IC is 180 ms, however the Mosfets are not turning on again, when the battery relaxes.

anushka khanna
Prodigy 30 points
Part Number: BQ77905

Tool/software:

Hi, 
What could be the reasons for the BQ7790518 IC with overvoltage cutoff as 4.25V to not close the path again. It detects OV in a battery pack of 8S, cuts off the charging current. But according to my understanding the battery will relax and take the voltages below the threshold and the FETs should close again right? 
This did not happen. 

Could someone help in figuring out why this could be happening? 

  • 0
    Prodigy 30 points

    I checked the hysteresis , according to me the battery is not relaxing to below the hysteresis of 200mv. Can I do something to reduce this hysteresis? Or something else by which the MOSFET closes path. 

    For 4.25V cutoff, after hysteresis the IC will reset at 4.05V/ cell. However upon relaxing, the voltage reaches around 4.17V. So it is not allowing more charging. Can I do something to help in this scenario?