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LM5158: LM5158

CHI JONG JANG
Prodigy 40 points
Part Number: LM5158

Tool/software:

I'm considering implementing an isolated flyback converter of 60V and -60V double output rail using LM5158. I'm going to use the quickstart calculator provided by TI, but it's difficult to select Lm. Is there any product that is readily available on the web that you can recommend?
I'm going to use it as a positive power source for the opamp, and I need 100V, 1.5A as an output.

  • 0
    TI__Genius 12925 points

    Hi Chi,

    Thanks for reaching out.

    What is the input voltage range for your design?

     What is the output voltage? Vout = +-60V or 100V? It is not clear to me from the text above. And what is the total outpot power?

    I can recommend using the power stage designer in parallel to the quickstart calculator: https://www.ti.com/tool/POWERSTAGE-DESIGNER

    Best regards

    Moritz

  • 0 in reply to Moritz
    Prodigy 40 points

    Sorry for the confusion, I'm looking for a ±60V DCDC for opamp power.
    The input is a 12 Vdc power supply, and the current to be used is a maximum of 1.5 A.
    I tried using calculator and designer tool as below. Is there any problem?

  • +1 in reply to CHI JONG JANG
    TI__Genius 12925 points

    Hi Chi,

    There are a few problems:

    - 2200kHz is way to high for a flyback. I sugest around 200kHz for this application.

    - The max. current of the internal switch is only 3.26A. This will not be sufficient. (You can see this when clicking on the FET in power stage designer)

    - You need a flyback transformer, not a standard couples inductor because a flyback needs an airgap. Also you need 2 output windings to get a positive and a negative rail.

    Best regards

    Moritz