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TPSM33625: PSpice for TI

Yuta Nishie
Genius 4925 points
Part Number: TPSM33625

Hi,

The PSpice for TI simulation model is used to verify the operation of TPSM33625. We created a 24V→5V Buck circuit and a 5V→-5V inversion circuit, but the simulation cannot be performed properly. Could you tell me where to change in the attached circuit diagram?

Overshoot occurs in the step-down circuit. Output is not possible in the reverse circuit.

TPSM33625.pdf

I changed the condenser connected to the boot pin to a 1G ohm resistor and added a Zener diode to the output stage of the inversion circuit, but it didn't work well. I wanted the boot pin to be Non-connect, but I couldn't run the simulation, so I connected the resistor.

Best Regards,

Nishie

  • 0
    TI__Guru 72035 points

    Hello

    The model is not designed for an inverting application.

    You will need to float your input supply as shown in the attached application

    note and try the simulation again.

    For the buck simulation, you might try to increase your load current and see if the 

    overshoot improves.

    Thanks

    0211.snva856a.pdf

  • 0 in reply to Frank De Stasi
    Genius 4925 points

    Hi Frank-san,

    Thank you for your reply.

    Is it correct TPSM33625 can be used to output negative voltage? When the input power was floated, it started for a few ms and then stopped working.

    I cannot get circuit information for negative voltage output from Webench, so I would like to know a tool that can input input input/output conditions and output a reference circuit. Is there such a tool?

    Best Regards,

    Nishie

  • 0 in reply to Yuta Nishie
    TI__Guru 72035 points

    Hello

    I don't think we have a tool for designing an inverter with this device.

    The best way to proceed is to use the application not that I provided and then

    test your design on an EVM.  The TPSM33625 should be able to work as an inverter,

    but it must be tested on the bench to ensure it meets all of your requirements.

    Thanks

  • 0 in reply to Frank De Stasi
    Genius 4925 points

    Hi Frank-san,

    Thank you for the information.

    I made the following circuit based on the information you gave me. However, an error occurred and the simulation could not be performed. Could you tell me where to fix it? Or I would appreciate it if you could expand the modified circuit.

    INVERT.DSN

    Best Regards,

    Nishie

  • 0 in reply to Yuta Nishie
    TI__Guru 72035 points

    Hello

    I got an error when I tried to open your file.

    However, do you have a ground symbol on your schematic ?  You will still need a ground symbol.

    Also, try to connect a large value resistor between the BOOT and SW pins.

    Thanks

  • 0 in reply to Frank De Stasi
    Genius 4925 points

    Hi Frank-san,

    Thank you for letting me know the details of the revision.

    The simulation worked, but the output voltage became 0V. Could you tell me what is wrong with my circuit? Or could you provide me a model of an inversion circuit that can make 5V to -5V?

    Best Regards,

    Nishie

  • 0 in reply to Yuta Nishie
    TI__Guru 72035 points

    Hello

    Try putting a probe on the top of R5.

    Also, try using a step voltage source on V2, rather than D.C.

    If that does not work, then send us your new design and we will look at it.

    Thanks

  • 0 in reply to Frank De Stasi
    Genius 4925 points

    Hi Frank-san,

    I tried using a step voltage source. But it didn't work well.

    I attach the circuit model. I would appreciate it if you could check it.

    I can only attach DSN files. Are there any other files I need?

    6012.INVERT.DSN

    Best Regards,

    Nishie

  • 0 in reply to Yuta Nishie
    TI__Guru 72035 points

    Hello

    We will look into this issue and get back to you as soon as possible.

    Thanks

  • +1 in reply to Frank De Stasi
    TI__Mastermind 22060 points

    Hi Nishie-san,

    I was unable to get your schematic working on my end, so I started over using the model found on ti.com. I think the issue may have been that the simulation needs to run longer. The simulation I ran was set for 4ms. The output voltage does not start to rise until ~200us. I've attached some screenshots of my schematic and results:

    Please note that when using a model to simulate IBB in this way, the positive output voltage measured in simulation will be a negative voltage when the proper measurement is taken on the bench. As is shown, I am able to achieve the Vout = -5V at Vin = 5V. Please refer to this application note for more details on IBB design: https://www.ti.com/lit/an/snva856b/snva856b.pdf

    I have also attached a zip file of the PSPICE project I used. Please refer to the "startup" schematic. TPSM33625_TRANS.zip

    Best regards,

    Ridge

  • 0 in reply to Ridge Lahti
    Genius 4925 points

    Hi Ridge-san, Frank-san,

    Your support was very helpful. Thank you for your great support.

    Best Regards,

    Nishie