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BQ25619: BQ25619 output voltage ripple

Jimmy Lai
Expert 6845 points
Part Number: BQ25619
Other Parts Discussed in Thread: TPS630250,

Dear Team,

Our customer  follow the EVB schematic, but the voltage get big ripple around 500mV.

Could you guide us how to check it?

Thanks a lot!

Jimmy

  • 0
    TI__Guru** 102395 points

    Hello Jimmy,

    Can you share the schematic and layout? We will need to take a look to do further debug.

    What kind of scope probe are they using for measurement?

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    TI__Expert 6845 points

    Hi Keller,

    We appreciated your great support!

    The schematic and Layout as below for your reference.

    Many Thanks,

    Jimmy

  • 0 in reply to Jimmy Lai
    TI__Guru** 102395 points

    Hello Jimmy,

    It looks like the ripple is very low frequency, do you have your system attached during the test? It may be due to the system load and not the charger. This is not from the switching ripple. Can you also capture waveforms of the battery current/voltage along with the bus current/voltage?

    The layout and schematic look okay from what I can see.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    TI__Expert 6845 points

    Hi Wyatt,

    We appreciated your great support!

    Customer have a question as below:

    Why the TPS25619 need to consume that much current to keep waveform smooth ?

    (waveform) 

    1.No load :TPS25619 have 15Hz ripple

                      TPS630250 -> perfect

     

    2.33 ohm resister load :120mA 

                      TPS25619 have 15Hz ripple

                      TPS630250  perfect

    3.10 ohm load:420mA

                  TPS25619 perfect

                  TPS630250 perfect

    Best regards,

    Jimmy

  • 0 in reply to Jimmy Lai
    TI__Guru** 102395 points

    Hello Jimmy,

    Can you share your registers settings and your system specs (input voltage, input current, charge current)? Are you measuring the ripple on the system of bat pin?

    Also just to clarify you're still wondering about the bq25619? I won't be familiar with the TPS chipset.

    Sincerely,

    Wyatt Keller 

  • 0 in reply to Wyatt Keller
    TI__Expert 6845 points

    Hi Wyatt,

    Thanks for your support!

    I have checked it with our customer:

    1. They don't set the register .

    2. They don't connect the battery , and they check the voltage that is from vout.

    Could you help to why the TPS25619 need to consume that much current to keep waveform smooth ?

    Many Thanks,

    Jimmy

  • 0 in reply to Jimmy Lai
    TI__Guru** 102395 points

    Hello Jimmy,

    So they use all default register values?

    They don't connect the battery during this test or the measurement is not on the battery? Do they see the voltage ripple on VSYS? Can you share scope captures of VBUS, VSYS, VBAT, and VSYS?

    Sincerely,

    Wyatt Keller