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BQ76952: Recover from OCD

Yue TANG
Expert 8695 points
Part Number: BQ76952

Hi experts,

from datasheet, it looks like only plugging in charger can recover from OCD, it is not enough for real product.  Is there any other way can make this device recover from OCD?  can it recover based on discharge current decline after a  time window?Thanks.

7.3.4.7 Overcurrent in Discharge 1, 2, and 3 Protections

When an OCD1, OCD2, or OCD3 fault is triggered, the device will turn off the DSG FET if configured for
autonomous FET control using Settings:Protection:DSG FET Protections A[OCD2][OCD1] or
Settings:Protection:DSG FET Protections C[OCD3] configuration bits. The device will recover when a
charging current is detected greater than or equal to Protections:OCD:Recovery Threshold for
Protections:Recovery:Time duration.

  • 0
    TI__Guru* 81034 points

    Hi Yue,

    The OCD:Recovery Threshold can be set to a negative value. This way when the FET turns off the recovery threshold will be reached. However, it may also be good to use the OCDL feature to avoid cycling continuously if there is a weak short.

    Best regards,

    Matt 

  • 0 in reply to Matt Sunna
    TI__Expert 8695 points

    Matt,

    The datasheet is not clear about how to recover based on time,Looks like it involves charging current. My customer want to automaticlly recover when discharging current back to normal. how to do this?

     

  • 0 in reply to Yue TANG
    TI__Guru* 81034 points

    Hi Yue,

    Like I said, the OCD Recovery threshold can be set to a positive or negative value. They can set a negative recovery current for discharge. The OCDL recovery threshold can also be set to a negative value. 

    However, you may want to avoid the situation where there is a soft short and the battery keeps recovering from the fault condition only to repeat the fault being triggered. So maybe you can set OCD to recover based on a negative current, but set OCDL to recover based on a positive (charging) current. Otherwise the fault may just cycle on and off repeatedly.

    Best regards,

    Matt

  • 0 in reply to Matt Sunna
    TI__Guru* 81034 points

    Hi Yue,

    I should also point out that when the OCD protection is triggered, the DSG FET is turned off which means the current will go to zero. So there is no way for the current to return to the normal levels. I just want to make sure that is clear.

    Matt