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  • TI Thinks Resolved

WEBENCH® Tools/LM5023: LM5023_QR Flyback Power supply

Prodigy 150 points

Replies: 17

Views: 531

Part Number: LM5023

Tool/software: WEBENCH设计工具

Hi!

I use LM5023 to develop a boost power supply, VCC auxiliary supply voltage is 24 V, power MOSFET voltage is 3 V. Request to raise 3V to 36V, there are problems in debugging, special help support, thank you!

The current problem is that the output voltage can only be adjusted to 13V can not be raised, transformer parameters for PQ2016, primary use 3TSs, auxiliary winding is 4TSs, output winding is 18TS.LP:2.8uH.

This is a two-way DC/DC converter.24VTO5V5A_1030.pdf

  • Hi Chime xia,

    We will get back to you on this soon.

    Thanks and Regards,
    Atul
  • In reply to Atul Kulkarni9:

    Thank you, Atul Kulkarni23!

    Today I have a new development in debugging, the converter can rise to 17 V, and will run in blocking mode. But not with load.

    I did this by debugging the Optocoupler resistor in charge of the resistor and the voltage divider of the TL431, but when the output voltage continues to increase by adjusting the divider resistance, the output voltage reaches 17V and goes into blocking mode. I think it should have a lot to do with the feedback loop design.

    Thanks again! I need your support now!

    Chime xia

  • In reply to chime xia:

    Hi Chime ,

    Could you please share the input/output conditions of the designs. You can also share the design using public share link.
    Also please let us know if the design is done using Webench.

    Thanks and Regards,
    Atul
  • In reply to Atul Kulkarni9:

    Thank you very much!

    My design requirements:

    1. Input voltage: dc 2.7 V to  3.3 V, current 5 A;

    2. Output voltage DC 36 V.Output current is not required, as long as the efficiency is over 82%.;

    3. Require isolation;

    4. Efficiency 82% min;

    The design has been modified with reference to WEBENCH.

    The schematic diagram has been attached, please refer to it.

    Thank you for your reply, I will continue to look forward to your reply!

    Thank you !

    Chime xia

  • In reply to chime xia:

    In addition, forget to explain,I didn't find a boost topology on WEBENCH, only a step-down topology.
  • In reply to Atul Kulkarni9:

    Hi Atul,

    Do you have any comments on this issue?

    Here I also attached the layout, thank you.

    24VTO5V5A.pdf

  • In reply to Lin Zhao:

    Hi Atul,

    Help to see if the boost topology circuit designed(3V->36V) is feasible?

    Thank you
    Jerry
  • In reply to Jerry Hsueh:

    Hello Chime Xia,

    I think the 17V on the output is actually your reflected voltage from the primary ie: 3Vin*Nps this is because the controller is not turning ON. The reason for that is the Vcc turn-ON of LM5023 is 12.5V and with the givenm turns ratio Npa the Vaux is only 4V.
    Please plot Vcc, Vout, OUT to examine this, you will see VCC is sitting @ 4V and OUT is doing nothing.

    Regards,
    Sonal
  • In reply to Sonal Singh:

    Hi Sonal,
    Thank you for your reply!
    I think negative-VAUX is 4V, but Vaux is 36V * Nsa when it works, and my Nsa is 0.33, so VCC=36*0.33=11.3V; actually has a VCC greater than 11.3V when it's no load.

    thank you
    Chime Xia
  • In reply to chime xia:

    Hi Chime,

    May you please plot OUT, VCC and VSD pin waveforms to look into this, I would like to understand the power demand from the controller during load conditions.

    Regards,

    Sonal

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