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BQ76942: Battery Reverse Polarity Protection

wang gang
Prodigy 20 points
Part Number: BQ76942

Tool/software:

Hi, TI team.

I have a question about bq76942.

In my case the battery consists of 4 removable 18650 lithium cells . The user may accidentally insert one or more of the cells in reverse polarity.

I have reviewed the VC0 ,VC1,VCn Pin Equivalent Diagrams for the BQ76942，These pins have integrated protective diodes internally, and these diodes, along with external balancing resistors, will clamp the voltage at the VC0, VC1, VCx pins to a safe voltage range. Therefore, when the batteries are connected in reverse, the BQ76942 is not so easily damaged. Is my understanding correct?

Best Regards!

  • 0
    TI__Genius 17795 points

    Hello Gang,

    Unfortunately, this part does not offer battery reverse polarity protection if the user accidentally insert's them incorrectly.

    Best Regards,
    Alexis

  • 0 in reply to Alexis_H
    Prodigy 20 points

    Hi Alexis_H,

    Thank you for your reply, I have another question I need to ask you.When I use the external balance circuit, can the the cell input resistors Rn be higher than the recommended maximum resistance of 100 ohms? For example, use a resistance value of 1K. The measurement of  the voltage for my application does not need to be particularly accurate.

    Best Regards.

  • 0 in reply to wang gang
    TI__Genius 17795 points

    Hello Gang,

    Yes, you can use a higher resistance value for the cell input resistors, however, as you already know, we recommend a maximum resistance of 100 ohms. Section 2.5 Voltage Measurement Accuracy During Balance of the Cell Balancing With BQ769x2 Battery Monitors application note, should tell you more about how much the accuracy might differ as well.

    Best Regards,
    Alexis