LM 2576 HV CONVERTER

Discussion in 'The Projects Forum' started by HBB, Sep 3, 2016.

  1. HBB

    Thread Starter New Member

    Mar 3, 2012
    25
    1
    Hello

    I am experimenting with LM2576 HV to convert 48 VDC to 15 Volt.

    Circuit is working well. But when batteries are under charge Vin approaches 55 Volt (regulated by a PWM Morningstar microcontrolled device). That is dangerously close to 60 V, the max Vin rated.

    So a couple of times The 2576 burned out. Both tries the circuit lasted more than a month, working 24/24.

    I can reduce the input V connecting some diodes in series, and sacrificing efficiency.

    But I suppose there are better solutions. I browsed for higher voltage ICs, but did not find.

    Output C is standard electrolytic, not ESR. Can that harm ?

    Thanks for your time !

    Kind regards, Horacio
     
  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,791
    1,103
    The higher the ESR of the cap the greater will be the ripple voltage.
     
  3. ronv

    AAC Fanatic!

    Nov 12, 2008
    3,283
    1,245
    Pretty close.
    What you might try is to use only 3 batteries to power it and see how it does. This will unbalance your batteries a little, but probably not bad if they are big ones.
     
  4. Phil916

    New Member

    Feb 3, 2010
    2
    0
  5. takao21203

    Distinguished Member

    Apr 28, 2012
    3,577
    463
    Ive used external MOSFET and gate drive transformer with this IC.
    It worked for high voltage, but extremly sensible for EMI when triggering photo flash the IC would latch off.

    You need to build a discrete converter there are not many ICs for high voltage.
     
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