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PMP23421: Switch Time Test and Inductor Issue

Francis Jiang
Expert 3580 points
Part Number: PMP23421


Tool/software:

Hi Team,

Customer would like to know below details for this reference design:

  1. Do you have charging and discharging switch time test report?
  2. Could you please share all the inductors here? BOM list only has 1 value. And why the charging circuit is a separate phase? Is it because the inductor is different from the discharging circuit?
  3. Could you please provide the design method and material of the inductor you used?

Thanks in advance.

BRs,

Francis

  • +1
    TI__Prodigy 660 points

    Hi Francis,
      Reply as follows...

    1. Do you have charging and discharging switch time test report?
    No, It still under development.

    2. Could you please share all the inductors here? BOM list only has 1 value. And why the charging circuit is a separate phase? Is it because the inductor is different from the discharging circuit?
    2.1-All inductors are the same one.
    2.2-Use a different path from discharge boards in this design.
    2.3-Yes.

    3. Could you please provide the design method and material of the inductor you used?
    We are choosing the choke(inductor) by consider the rating of saturation current, ripple current and equivalent DCR.

    Regards,

    Richard

  • 0 in reply to Richard Yin
    TI__Expert 3580 points

    Hi Richard,

    Thanks for your reply, and two further questions here, thanks in advance:

    1. Could you please help test the #1? Customer need this data as they are developing a BBU project.
    2. You mentioned all inductors are the same, but you also answered "yes" in 2.3. So the charge circuit and discharge circuit are same, right? You just use different path to do design, no other technical reason.

    BRs,

    Francis

  • 0 in reply to Francis Jiang
    TI__Expert 3580 points

    Hi Richard,

    One more question here, whether the BUCK work in CCM mode or DCM mode, if there is hard switching, is the efficiency higher than Si/SiC?

    BRs,

    Francis

  • +1 in reply to Francis Jiang
    TI__Prodigy 660 points

    Hi Francis,

    1. Due to the charge/discharge transition time still under development. So I need to check with PL for details on the progress.

    2. Sorry for misunderstanding on 2.3. Correct, the inductors are all the same on each board.

    Regards,

    Richard

  • +1 in reply to Francis Jiang
    TI__Prodigy 660 points

    It is in CCM mode. The LMG3100 GaN FET efficiency is higher than Si FET due to the switching losses being lower than Si FET. We didn't compare GaN with SiC FET. So I'm not aware which FET is better.