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WEBENCH® Tools/LM5161: LM5161 flybuck configuration for 3V3 with dual supply

Part Number: LM5161

Tool/software: WEBENCH® Design Tools


I am trying to simulate LM5161 for a fly back configuration where I need one Isolated power supply of 3V3@150mA and another non-isolated one at 3V3@1.2A

As for suggested configuration here it is designed for 12V at 500mA each.

I have tried downloading simulation model from component page

But, I am unable to edit components as there properties are missing (like transformer and LM5161). So, its difficult to simulate for 3V3.

Another thing, which I have tried is using WEBENCH POWER DESIGNER to design it. But, It feels like it is lacking a lot of components as compares to this circuit here

This is the suggested circuit by WEBENCH:

Any help will be really appreciated.



  • Hello

    Let me speak with our engineering team and I will get back to you soon.


  • Hello

    On the product page you will find both component calculators and the TI SPICE simulator and models.

    Please try one of the component calculator spreadsheets, they may be of some help.

    Also, you should be able to use the simulator models to design a fly-buck.


  • Hi Frank,

    Thanks for your response.

    I will try to look into component calculators, although I have already tried simulator models and I am unable to edit parameters except resistor and capacitor values, am using Pspice.

    Also Is it possible to get more than or equal to 1.5A@3V3, where output is rated for 1A@12V?

    And how reliable and practical Webench's suggested designs are for direct adoption.



  • Hello

    I think that the webench is a good place to start.  However, the best way to confirm your design

    is to use an EVM and modify with your values and test.

    The maximum load will depend on the particular converter and the application design.

    I am passing this post to one of my colleagues with more experience in TISPICE to help you further.


  • Hi Anurag,

    If you want to edit parameters for components like the transformer, I would recommend using the 'Inductor Coupling Symbol' in PSPICE. This will allow you to edit parameters such as inductance, turns ratio, core material, coupling coefficient, etc. This way you can simulate specific coupled inductors based on their datasheet values.

    You can find this by going to: Place->Pspice Component->Passive->Coupling.

    For information on using the inductor coupling symbol:

    Additionally, if you need more direct assistance with your simulation file I can do that as well.


    Harrison Overturf

  • Hey Harrison,

    Thanks for your suggestion, that was my idea as well to place general component and edit values according to the datasheet as I was unable to edit component from simulation model.

    And I really appreciate your assistance, but right now my requirement has changed a lil and I am moving on with a different component which is suitable.