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TPS54386: Current Supply Issue with the regulator

Kamesh Lakhwani6
Intellectual 765 points
Part Number: TPS54386

Hi,

We are using TPS54386PWPR IC for our application. Here, we are using battery charging IC at +5V output of the regulator. The issue is it does not provide enough current to charge the battery. Below is the image for the schematics that we are using. Please let me know the root cause due to which this is happening.

  • 0 in reply to Kamesh Lakhwani6
    TI__Mastermind 29550 points

    Hi Kamesh,

    I looked in to the SCH, mostly it looks good with no sure indication why the charger is not charging the battery, here some comments to further double check

    • Input cap values look ok, just make sure the voltage rating is meeting the max VIN requirements
    • What is the value of C86 and C79, I am expecting to be around 100uF to meet the ripple requirements.
    • VCC_SYS is set to 3.32V
    • VCC5 is set to 4.97V. Now make sure the charger (At the pin) is getting at least 4.7V or so to allow charge. Because you may have some drop in the path between the VCC and VIN of the charger, just probe that pin to make sure is not dropping.
    • I would do the same thing on the input to the TPS device. Make sure to get enough input voltage and is not limited.
    • Make sure D41 and D40 is not clamping VOUT1 and 2. I cannot read the clamping voltages
    • BP and ILIM are connected together, so the current limit is set to 4.5A nominal.

    To debug this even further, here the measurement to do: .

    1. Remove the connection between the charger and the TPS device:
      1. Load the VOUT and VOUT2 of the TPS and see of they provide the expected needed
      2. supply the charger with external supply and see if it charging
    2. Based on a and b we should isolate where the issue is coming from.

    Thanks

    Tahar