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LM3150 simulation failures in Webench

Aaron Walsh
Prodigy 30 points
Other Parts Discussed in Thread: LM3150

Dear forum members,

I am trying to use Webench to simulate a 24Vdc to 12Vdc converter using the LM3150 but without success.

The Startup simulation shows the output voltage rising to just 0.4V and then falling back to 0V within 700uS, never reaching 12V.

The Load Transient simulation from 0.01 - 6.00 amps produces unuseable results.

I would also like to simulate a zero load condition.

Any help would be greatly appreciated.

Aaron

 

Configuration for LM3150

Vin Min = 23V

Vin Max = 25V

Vout = 12V

Iout = 6A

Amb. Temp =40

 

  • 0
    TI__Intellectual 2155 points

    Hi Aaron,

    I received your question regarding the simulations for LM3150. I've seen issues with the simulations before, and sometimes they have to do with the FET and the driver models interacting together. Can you try selecting an alternate FET in the BOM and running the simulation again? Maybe that might correct the issue. If not, we can try to figure something else out.

  • 0 in reply to Kevin Ip
    Prodigy 30 points

    Hi Kevin,

    Thanks for your very fast reply.  Is there a way to select another FET part number in Webench ?  When I select the FET in the schematic and click 'Edit' I am presented with a list of FDD8647L FET's of differing footprints but I have not found a way of selecting a completely different part number.  Obviously it would be best to select a part that Webench already has a simulation model.

    Best regards

    Aaron

  • 0 in reply to Aaron Walsh
    TI__Intellectual 2155 points
    Hi Aaron,
    Sorry for the month long delay.  I only saw your reply posted just now.  I tried your design inputs and ran a LM3150 WEBENCH® design and it looks like only the FDD8647L FET is chosen for the high side FET.  I think because of the design inputs, this limits the BOM components that the tool can suggest.
    As a suggestion, you can try reducing the output current and running a design to get other types of FET's and then running the simulation.  Unfortunately, for your design inputs the FDD8647L is the only one recommended for the high side FET.  I was able to see a bunch of different FET's when running a design at 3.0A.
  • 0 in reply to Kevin Ip
    Prodigy 30 points

    Hi Kevin,

    OK, thanks for trying, your help is much appreciated.

    Best regards

    Aaron