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LM5175: I'm wondering the LM5175 chip can use in parallel for a 3.5KW output

feng
Prodigy 170 points
Part Number: LM5175
Other Parts Discussed in Thread: LM5170, UCD3138, LM5176

Hi, TI's expert:

   I used a single LM5175 chip for 20V ,8A output design and it works well.

   But now, I need design a 3600W output rating power, the output voltage is 24V and 48V(both need be met).

   which means the design should afford more than 150A(75A in 48V output) current . so my iissue is , can the LM5175 use in parallel ?

   if can use in parallel, like, I can parallel it with 8 lanes, then, the current less than 20A in single LM5175.

  • 0
    TI__Guru 61075 points

    Hello user6322596,

    For 2 converters in parallel, I would recommend following the solution in this app note: LM5176 Power Sharing Between Two Parallel, Four-Switch Buck-Boost Converters (ti.com)

    For further phases you would need to add further OpAmps and reference all to the same signal from the first phase. Altough I think it might be possible, I think it will be difficult to realize as small changes in the reference signal might come already just because you need to do a layout that is not 100% the same for all converters.

    BTW, for 8 phases you should synchronize the converters with an external phase shifted clock.

    What is your input voltage? Possibly the boost converter LM5170 fits your needs here better.

    Best regards,
    Brigitte

  • 0 in reply to Brigitte
    Prodigy 170 points

    hi, Brigitte

       Thanks for your reply.

       I'll check your advice carefully and then evaluate the feasibility of the case.

       I"ll reply in two days.

  • 0 in reply to feng
    Prodigy 170 points

    hi, Brigitte

       sorry for the delay.

       I've read the application note carefully. And I agree with your opinion that for more than 2 or 4 phae's application, it's quite difficult to kepp the layout symmetrically to keep the accuracy of power share and aviod the disturbance of other signals.

       And the input Voltage range is around 20V ~ 70V. the max current may over 100A. As for the output voltage, is 24V and 48V.

       From the LM5170 spec and EVM. I just find the Buck or Boost topology, I want to know that is the LM5170 can meet my need.

       Thanks.

  • 0 in reply to feng
    TI__Guru 61075 points

    Hello Feng,

    LM5170 is buck in one direction and boost in the other. This means it cannot fill your need of buck and boost in the same direction. This is a pitty.as it is easily stackable.

    Maybe you might think about a resonant converter, similar to this reference design: PMP20978 reference design | TI.com

    I will forward your thread to a team that possibly has the better controllers for such a high power design.

    Best regards,
    Brigitte

  • 0 in reply to Brigitte
    TI__Guru 73685 points

    Hello Brigit,

    This is not a device that HVC generally supports.  I will forwarded to someone who can figure it out.

    Regards,

  • 0 in reply to Mike O'
    TI__Guru 73685 points

    Hello Brigit and Feng,

    The LM5170 is a bidirectional controller.  You might be able to do this with a C2000 or a UCD3138.  If you have any questions regarding these devices please repost in the e2e with C2000 and UCD3138 in the thread title.  So the appropriate applications engineer can answer these questions for you.

    Regards,

    Mike O

  • 0 in reply to Mike O'
    Prodigy 170 points

    hi, Mike

       It seems the solution of C2000 and the UCD3138 belongs to DSP or Digital contorllors. It is a band-new area for me and I nerver did this before.

  • 0 in reply to Brigitte
    Prodigy 170 points

    hi, Brigitte

       I notice that the 2 phase parallel solution use the LM5176, and I wanna comfirm that the LM5175 can do the same thing.

  • +1 in reply to feng
    TI__Genius 10725 points

    Hi Feng, this question was routed to me, but I am not familiar with the LM5175/6 products. I will send this to Brigitte who answered your original question.

    It sounds like the same question that you originally asked. Nonetheless, I will assign this thread back to Brigitte.