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LP3918: Current of battery is flowing backward to CHG_IN pin in the absence of VBUS

James Lee76
Prodigy 30 points
Part Number: LP3918

Is there any way to control the switch from the block of liner charger in LP3918 between BATT and CHG_IN? The reason I ask is because somehow current from battery is flowing backward to the pin of CHG_IN in the absence of VBUS. There is a circuitry connecting to CHG_IN pin.

  • 0
    TI__Genius 10885 points

    Hi James,

    You may want to ensure set_LDOmode is 0, but there are no hidden controls for the charger, and the device internally has a reverse current blocking diode.

    What else is connected to VBUS and how are you measuring this current?

    Best Regards,

    Rick S.

  • 0 in reply to Richard Solarski
    Prodigy 30 points
    What does LDO mode mean?
    May I reset the bit of EN_CHG to disable charger?
    For my application, VBUS at CHG_IN is connected to iPad. Try to avoid any current from battery to iPad through the pin of CHG_IN.
  • 0 in reply to James Lee76
    TI__Genius 10885 points
    Hi James,

    LDO mode is only available for the LP3918TL_L, should not be used with a battery, and allows the BATT rail to be utilized as a 4.2V supply.

    You can experiment with the charger bit, does clearing this bit remove the observed current?

    This device has a reverse current blocking diode for the charger, so this should not be an issue. Can you verify how you are measuring this current?

    Best Regards,
    Rick S.