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WEBENCH® Tools/LM5022: change the value

Part Number: LM5022

Tool/software: WEBENCH® Design Tools

Hi Team,

I did the structure of a boost on webench, and i found the result below,

Vin: 8 V
Vout :  125 V / 0.2 A
on the result i found the value equal 33uH, i want to increase this value. What is the max value that i can put it??
and
 if i change this value, what i need to change other value of the components ?
Best regards
  • Lakhal,

    You can change the inductor from 33uH to a bigger value if you like. Current design is for 30% ripple of inductor average current. You could go as much as 100uH and would have about 10% ripple in the inductor. The inductor change can be done using "BOM" -> "Select Alternate Part" for inductor row. Once in that page, you can update the upperbound on inductor value and click Search to list all applicable inductors. You can look through the list and choose an inductor of your choice.

    You will at least need to ensure the current sense resistor Rsns, Rs2 and compensation components are updated to ensure good performance. You can use eq 36 from datasheet to recalculate Rsns value and eq 40 to calculate Rs2. And, to recalculate compensation you can use the "Re-Comp" tab and click on autocompensate button after you change loop response requirements like phase margin, crossover frequency, etc. And, then apply changes to design for the components to be updated.

    Regards,

    Amod

  • In reply to Amod Vaze:

    Hi Amod,

    thank you for your return, it is very clear, but in the equation 36 and 40 what is the ''VCL'' ?

    i want to simulate my schematic, but i found the fault simulation, i don't know why. the fault is in attached figure.

    and i have not changed any characteristics,

    best regards,

    Aymane LAKHAL

  • In reply to Lakhal aymane:

    Hi Lakhal,

    "VCL" corresponds to current limit comparator threshold. You can consider it as 0.5V as mentioned in the data-sheet.

    Also regarding the simulation error, Could you please share the WEBENCH design for which you are observing this issue ?

    Below image describes the steps to share the design.

    Thanks and Regards, 

    Harish

  • In reply to Harish K R:

    Hi Harish,

    thank you for your return,

    here is the link for webench design:

    webench.ti.com/.../SDP.cgi

    best regards

    Aymane LAKHAL
  • In reply to Lakhal aymane:

    Hi Lakhal,

    Thanks for sharing the design. We are working on this issue.
    We will keep you posted on the updates regarding the same.

    Thanks and Regards,
    Harish
  • In reply to Harish K R:

    Hi Harish,

    i posted it been 10 days and I have not yet received an answer for my problem.

    I'm still waiting for an answer.

    Best regards.
    Aymane LAKHAL
  • In reply to Lakhal aymane:

    Hi Lakhal,

    Apologies for the delay.
    The design has selected Ideal MOSFET.
    There is a generic simulation issue w.r.t Ideal MOSFET. We are working on finding alternative to resolve this issue.
    We will keep you posted on the same.

    Thanks & Regards,
    Harish
  • In reply to Harish K R:

     Lakhal,

    The WEBENCH SPICE model has issues that need to be addressed and this will take around 3 weeks.

    As an alternative,  you can verify simulations in PSPICE. The standalone PSPICE model is available at below mentioned link.

    Please feel free to reach out in case of any queries

    http://www.ti.com/product/LM5022/toolssoftware

    Thanks & Regards,

    Harish

  • In reply to Harish K R:

    Hi Lakhal,

    We are working on resolution of WEBENCH Spice model which is taking longer time than expected. Apologize for the inconvenience caused

    Kindly use standalone PSPICE model available at below mentioned link.

    http://www.ti.com/product/LM5022/toolssoftware

    Please feel free to reach out in case of any queries

    Thanks & Regards,

    Harish

  • In reply to Harish K R:

    Hi Lakhal,

    Thanks for your patience. We are working on this issue. We will keep you updated on the same

    Best Regards,

    Harish

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