Can LM2575 generate -24V DC signal

Discussion in 'Power Electronics' started by Oussama Zaidi, Jul 4, 2016.

  1. Oussama Zaidi

    Thread Starter Member

    Mar 1, 2016
    53
    0
    Hi
    Can LM2575 generate -24V DC signal if I use the adjustable version as an inverting switcher, I had read the datasheet but I can't figure if it is possible or not, in the datasheet it is written that it is possible to use the 12V output version in an inverting mode to generate -12V from the output, is it possible to do the same thing for the adjustable one? thank you for helping.
    Datasheet:http://www.mouser.com/ds/2/405/lm2575-n-405736.pdf
     
  2. eetech00

    Active Member

    Jun 8, 2013
    652
    112
    Hi

    Yes. The computation of the component values is basically the same.
    The difference is in the output topology.
     
  3. DickCappels

    Moderator

    Aug 21, 2008
    2,664
    634
    Look at figures 32 and 33 in the datasheet
     
  4. Plamen

    Member

    Mar 29, 2015
    36
    4
    Petkan:
    Yes, any Buck regulator could be re-configured as Buck Boost and produce negative output voltage.
    The whole circuit stays the same with the following exceptions:
    The GND node of LM2575 (with all connected parts) is freed from GND and re-assigned as negative output
    The output of LM2575 is grounded.

    Note that the circuit is powered from the sum of input and output voltage. No harm clamping the negative to GND with a diode, to prevent it from going positive (>0.8V). The fly-wheeling diode of the Buck may act in this role...but via the inductor.
     
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