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LM5020: DC to DC flyback converter 13 to 100V DC input 12V/10A Output

raj kumar
Prodigy 10 points
Part Number:

Tool/software:

Hi Sir,

This is Raj from XOMobility. I am currently working on an automotive DC-DC flyback converter project with an input range of 24V to 100V and an output of 12V/10A (120W). I would like to confirm whether the LM5020 can handle these power ratings.

Could you please provide guidance on this?

Best regards,
Raj

  • 0
    TI__Mastermind 19665 points

    Hello Raj,

    Thanks for reaching out to us via e2e.

    In general, as a rule of thumb, a flyback topology is suitable up to power levels between 50 and 100 Watt.

    The controller IC is NOT the limiting factor regarding the power level.
    It are the components of the power stage and especially the transformer.
    Especially a suitable flyback transformer which will fit the power-, space-, and budget requirements will be hard to find.
    Building a 120W flyback converter is doable but it will be challenging.

    The LM5020 can handle that but it is an old product.
    For new designs we would recommend using the LM5155 or LM5156 (with dithering).

    I know that these parts cannot be directly connected to a 100V supply, but - for thermal reasons - it is anyway not a good idea to use the integrated regulator for such high voltages.
    We would recommend using at least a Zener diode to limit the supply voltage for the controller IC and to distribute the power dissipation.

    The newer regulators also come with better collaterals, especially a QuisckStart calculator which is dedicated to this device.

    Independent of the choice of the controller IC I would recommend having a look at the documentation/collaterals that you can find on the product website of the LM5155 / 56.

    All information in this correspondence and in any related correspondence is provided “AS IS” and “with all faults” and is subject to TI’s Important Notice: www.ti.com/.../important-notice.shtml

    Best regards
    Harry

  • 0 in reply to Harry Hofner
    Prodigy 10 points

    Hello Harry,

    Thank you for your valuable information.

    I agree with your points. Could you please suggest any alternative chip for a 100V supply suitable for automotive applications?

    Best regards,
    Raj

  • 0 in reply to raj kumar
    TI__Mastermind 33115 points

    I agree with previous response that 120W flyback is probably asking too much, especially 12V/10A output. The right topology is likely push-pull or forward converter. I would probably start with PWM controllers here. Also, consider TI Power Stage Designer as a way to help understand the trade offs between different power topologies.

    Steve