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  1. #1
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    Simulate the TI's Demo board PMP7188 in LTspice

    Basically,it can work.
    But I discover that the value of Vin is digger than 36(typ Vin ESD) in the beginning.
    Click image for larger version. 

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    Theoretically, Vin should be clamped between 30~40.
    It is impossible that Vin>40.
    Is it a error of LTspice???
    Click image for larger version. 

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    plz help me with this problem.m(_ _)m

    PMP7188.rar

    •   Alt16th February 2017, 12:33

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    Re: Simulate the TI's Demo board PMP7188 in LTspice

    Hi,

    in the given picture I see the "5mA" condition. Did you take care about this?
    How do you limit this current?

    Klaus



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    Re: Simulate the TI's Demo board PMP7188 in LTspice

    KlausST

    Sorry!
    I didn't notice it!

    I don't know what it mean.
    I use resistor(R1&R2) to limit the current.
    Click image for larger version. 

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    •   Alt17th February 2017, 14:05

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  4. #4
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    Re: Simulate the TI's Demo board PMP7188 in LTspice

    Due to missing components, the circuit can't be simulated. If you post a simulation circuit, you should add all files that are not contained in a recent LTspice distribution.

    I might be either a model fault (Z-diode missing or inappropriately modeled) or a LTSpice problem.

    5 mA is a maximum rating for continuous current. The Z-diode should still have a clamping effect at higher currents.

    - - - Updated - - -

    I reviewed your circuit a second time. Looks like LM5021 misses a ground pin.

    - - - Updated - - -

    Second comment. I see that the LM5021 model uses global ground node 0. Should work, bad practice though.

    But there's no Z-diode model in the subcircuit. You may want to add it externally.


    1 members found this post helpful.

    •   Alt17th February 2017, 15:23

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  5. #5
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    Re: Simulate the TI's Demo board PMP7188 in LTspice

    FvM
    Sorry, it's my false that I didn't check the files.
    This is a new files I have checked.
    PMP7188.rar

    the LM5021 model has only just 7 pins.
    I will simulated in TINA-TI again.
    If I have any information or solution, I will reply here.

    In order to simulate optocoupler, I use Diodes and behavioral current sources as shown below.
    Click image for larger version. 

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    Last edited by gwdbsuccess; 20th February 2017 at 16:33.



  6. #6
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    Re: Simulate the TI's Demo board PMP7188 in LTspice

    Still missing symbols

    Click image for larger version. 

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    If you post a simulation circuit, you should add all files that are not contained in a recent LTspice distribution.
    Means, you unpack the archive, open the *.asc file and start the simulation with a standard Ltspice version.



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    Re: Simulate the TI's Demo board PMP7188 in LTspice

    FvM
    I changed the file name and uploaded the file again.
    PMP7188_2017_2_20.rar

    If you unzip, you will see the "LTSPICE MODEL" file .
    Click image for larger version. 

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ID:	136310Click image for larger version. 

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    Thankyou m(_ _)m



    •   Alt21st February 2017, 01:18

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  8. #8
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    Re: Simulate the TI's Demo board PMP7188 in LTspice

    Besides the missing Z-diode in LM5021 model, which can be easily added, what's your particular question?



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    Re: Simulate the TI's Demo board PMP7188 in LTspice

    My question is:
    Because Cvin(C7) should be shorted to GND, the Vin should be close to 0 in the beginning.
    The Z-diode shouldn't be a major cause this result.(Maybe I'm wrong)



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