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DC step down

Discussion in 'Power Electronics' started by Viju, Dec 18, 2017.

  1. Viju

    Viju

    12
    0
    Dec 15, 2017
    Hi,

    I got a AC 100-240V to DC 48V 3A 144W Power Adapter. What can I do to get an output of 32V 5A from this power supply?
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,214
    2,695
    Jan 21, 2010
    Find a buck DC-DC converter with an input range which includes 48V, an output range which includes 32V, and a current capacity greater than 5A.
     
  3. duke37

    duke37

    5,254
    726
    Jan 9, 2011
    With a wide range of input voltage, it is likely to be a switched mode supply. It should be possible to alter the feedback resistor to give 32V but it will not be possible to increase the current capability from 3A to 5A or the power from 144W to 160W.
     
  4. Viju

    Viju

    12
    0
    Dec 15, 2017
    Hi, could not find any buck converter with input greater than 40v. Can I use two buck converters and then connect the outputs in series to get 32v.
     
  5. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,214
    2,695
    Jan 21, 2010
    No (typically).

    Many buck converters have one output (ground) in common with the input. If you can find one with totally isolated outputs then you may be able to do this.

    But the problem is the input voltage.

    Or use something like this.
     
  6. Viju

    Viju

    12
    0
    Dec 15, 2017
    Thanks a lot. Really appreciate it.
     
  7. BobK

    BobK

    7,645
    1,663
    Jan 5, 2010
    However, you still cannot get 160W from a 144W power supply!

    Assuming you could find a buck converter that was 90% efficient, the most power you could get at 32V would be
    129.6 Watts, which equates to just over 4A.

    Bob
     
    (*steve*) and davenn like this.
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