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30V-32V to 24V DC/DC conversion IC

Justin Kittel
Prodigy 20 points
Other Parts Discussed in Thread: TPS54560, LM25116, LM25085A, LM5088, LM25117

Good Afternoon Gentleman, 

I need to add a 24V rail to my current PCP. The input voltage will range from 26V to 30-32V. I am looking at an output current as high as 4-5A. I found an IC that might work but I'm unsure. It is the TPS54560. It can handle the input voltage that I need but i am not sure that the output at 24V can handle up to 5A. If anyone has any suggestions for an alternate IC with these capabilities or can confirm that the IC previously stated can handle that much power please advise. Thankyou very much for your time. 

Justin

  • 0
    TI__Mastermind 35165 points

    The TPS54560 can support this but the power dissipation can be quite high for the higher input voltages. For 4-5 A continuous current the switching frequency will need to be kept low. For an idea of this I put it into WEBENCH and it selects a 200 kHz switching frequency. Also assuming a layout with similar thermal performance as the EVM, the TJ is estimated at 73.5 deg C at 4 A load and 107 deg C at 5 A load. Additionally the diode will get quite hot at this much continuous load current so it is good to start considering a synchronous solution.

    If this temperature is too high for the application I suggest looking into a controller instead. The LM25116 looks like a good starting point.

  • 0 in reply to Anthony F
    Prodigy 20 points

    Thanks for your help Anthony.

    I also found the LM25085A.

    Is you have a minute to see if that would suffice that would be great. 

    Thanks Justin

  • 0 in reply to Justin Kittel
    TI__Guru**** 191445 points

    It seems like that should work, butt LM25085A is supported by a completely different organization.  I'll alert them to your post.

  • 0 in reply to JohnTucker
    TI__Genius 11490 points
    LM25085A is a non-synchronous PFET controller. It can do 100% duty cycle. It should work.
    Another non-synchornous solution is LM5088.
    If you are inclined to use a synchornous solutions LM25117 is a good choice.