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BQ25887: Over-Discharge Protection

Part Number: BQ25887


I have some issue about BQ25887

First of all it looks like SNS pin is connected to boost converter output so I thought I can power the system from SNS pin and BQ25887EVM schematic support my idea. Is it possible.

Secondly in BQ25887: Where is the chapter "8.3.10 Battery protection" of the datasheet ? topic from forum it says "When the battery is discharged below VBAT_SHORT_HYS, the BATFET is turned off to protect battery from overdischarge" where is the BATFET? BATFET is controlling the SNS output? if not which pin is controlling by BATFET? What is the VBAT_SHORT_HYS value? I can not found any information about that.

I try to test Over-Discharge protection with BQ25887EVM. I connect my load to j2 connector and discharge the 2s Li-Ion battery with 1.7A. I thought when the Vbat discharged below 6.2V, SNS output will not power the load anymore but it did. I wait until 5.2V but it was still powering the load. What was wrong my system.

Thanks for your attention.

Best Regards 

  • Eren,

    This is a mistake in the datasheet. BQ25887 does not offer overdischarge protection as it does have an integrated BATFET, but rather an integrated sense resistor labelled RSNS.

    This will be addressed in the next revision of the datasheet.

    Best Regards,