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LM5156H: Boost Converter Specifications report an error in WEBENCH simulator

Aaron_Rangel
Intellectual 450 points
Part Number: LM5156H
Other Parts Discussed in Thread: LM5122

Hello,

I'd like to design a dc-dc converter (BOOST) which specifications are as follows:

Vin = 14,4V to 16V (coming from typical 4 Cell Li-On Battery, 4S1P)

Vout = 60V

Io = 10A

I've selected the LM5156H part and when I'm trying to use the Webench to start with the design I get a pop message error.

According to the datasheet, the input/output range is ok, so I do not know why Webench is reporting this error.

I know 600W is a huge amount of power, but want to know the output power limit here.

I attach some captures.

So, where is the limit when using this component? What about this error message?

Do I need to change the part? Is there any alternative recommended?.

Regards.

  • 0
    TI__Genius 11215 points

    Hello, 

    Thanks for reaching out. An output power of 600W is quite high for an asynchronous boost, did you also consider a synchronous boost design like for example with LM5123? I'm looking forward to your answer.

    Kind regards,
    EM

  • 0 in reply to EM
    Intellectual 450 points

    Hello EM,

    LM5123 is not suitable according to my specifications because it has an output voltage max of 57V. I need at least, 60V.

    My specifications, as I said in my previous post:

    Vin = 14,4V to 16V (coming from typical 4 Cell Li-On Battery, 4S1P)

    Vout = 60V

    Io = 10A

    So, I understand that LM5156H is not the more suitable device for 600W (Vo = 10, Io = 10A). It is too much for an asynchronous boost.

    Could you please confirm that this part is not adequate for this purpose?.

    We have some units and need to clarify where to put them in a design or not according to our needs.

    I have seen another device, LM5122, but the Webench is reporting that either the IC or Fet selected will be overheated.

    Is there an output power limit here again? If so, could you please help us and provide the best suitable device according to our requirements?

    I am looking forward to hearing from you.

    Thanks for your support.

    Regards.

  • 0 in reply to Aaron_Rangel
    Intellectual 450 points

    Hello EM,

    Did you see my last post?.

    I will appreciate a reply at your own convenience.

    Regards.

  • 0 in reply to Aaron_Rangel
    TI__Genius 11215 points

    Hello, 

    Thanks for your feedback. The LM5122 could probably be the best fit for this application, also because it has a multi phase capability and this might solve the issues related to the overheat of some components. Would you consider the LM5122 in multi phase configuration (see pg 30 of datasheet) for your application? At this link you can find a similar reference design: https://www.ti.com/tool/PMP9595 

    Kind regards,

    EM

  • 0 in reply to EM
    Intellectual 450 points

    Hello EM,

    Ok, as far as I know this could be a good approach in order to reduce by two the input current on each phase, so it would reduce the power consumption as well and therefore the size of inductor. 

    Just one thing, I asked you about the confirmation of avoiding use of LM5156H (asynchronous topology) according to my specs that you recommended me. Could you please confirm this?

    I am looking forward to your reply.

    Thank you for your support.

  • +1 in reply to Aaron_Rangel
    TI__Genius 11215 points

    Hello, 

    Sorry for the delayed answer and thank you for your patience. I can confirm that an asynchronous approach is not recommended in this case. 

    Kind regards, 
    EM