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TPS54519: TPS54519 MODULATOR GAIN (COMPENSATION NETWORK DESIGN)

Aaron_Rangel
Intellectual 440 points
Part Number: TPS54519
Other Parts Discussed in Thread: TINA-TI, TPS62869

Hello,

I am currently trying to design a step-down dc-dc converter with TPS54519.

The fact is that after reviewing the datasheet I am not able to design the compensation network.

I have seen a picture (Figure 28) in the datasheet that shows the open loop bode plot including both Filter output response and Modulator Gain.

The datasheet recommends using TINA-TI model TPS54519 to do so, but the model (SLVMBS8.TSC, TPS54519 TINA-TI Average Reference Design) shows the close loop response because a compensation network is required to be included in the circuit.

From my understanding and as far as I know and after confirming it in slva301.pdf document (see attached capture example for TPS40200D driver), I need output filter plus modulator gain to get the bode plot diagram and design the compensator network from this diagram. Output Filter (RLC) does not show the gain because is 1 (0dB) at low frequencies, obviously. (see attached RLC bode diagram example, slva301.pdf).

So, how can I get this (output filter plus modulator gain) bode plot diagram of the datasheet example (Figure 28)? What is the Modulator Gain of this TPS54519 driver?

Regards,

  • 0
    TI__Genius 14876 points

    Hello Aaron,

    SLVA301 refers to a voltage mode control DCDC converter.

    TPS54519 is a current mode control. This cannot be used to design TPS54519 compensation loop

    For the TPS54519, the approach to design its compensation loop is describe in the datasheet.

    Also, If you want simpler part to design without this external compensation loop.

    You can have a look at the TPS62869 family.

    Let me know if you have any other questions.

    Thanks a lot!


    Regards,
    Dorian 

  • 0 in reply to Dorian Brillet de Cande
    Intellectual 440 points

    Hello Dorian,

    I cannot change the part to a TPS62869 because is a customer requirement.

    So I have to keep forward with this TPS54519 driver.

    Ok, slva301 refers to a voltage mode control, you 're right.

    Anyway, how can I get the bode diagram that I asked you for? How can I manage this with TINA-TI driver model?

    There are two ways for compensation network design in the datasheet, and they don't get the same results.

    I have designed it in a spreadsheet and checked it. That's why I asked you this on this post.

    Can I send you my schematic in order to be checked?

    Thank you all in advance.

    Regards,

     

  • 0 in reply to Aaron_Rangel
    TI__Genius 14876 points

    Hello Aaron,


    Sure, you can send it to me either here or via private email if you prefer.

    Let me know!

    Thanks,

    Dorian

  • 0 in reply to Dorian Brillet de Cande
    Intellectual 440 points

    Hello,

    I have sent you via private email.

    Thanks,

    Aaron.

  • 0 in reply to Aaron_Rangel
    TI__Genius 14876 points

    Hello Aaron,

    Great!

    Let's continue this thread via private message then.

    I will come back to you tomorrow.

    Thanks a lot!

    Regards,
    Dorian