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Behavioral voltage source problem

Discussion in 'Circuit Simulation & PCB Design' started by alec_t, Dec 20, 2016.

  1. alec_t

    alec_t Well-Known Member Most Helpful Member

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    I wanted to use a behavioural voltage source to simulate a zero-crossing detector, but have run up against a problem: it appears to give up the ghost (in both LTspiceIV and LTspiceXVII) when the dV/dt of the waveform exceeds a quite modest value. Is there a parameter in Control Panel which can be tweaked to get round this?
    ZeroCrossFail.PNG
     

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  2. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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    hi alec,
    I added 1u step to .tran
    Eric
    0.1u also works.
     

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  3. alec_t

    alec_t Well-Known Member Most Helpful Member

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    Thanks Eric!
     
  4. dave

    Dave New Member

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  5. eTech

    eTech Active Member

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    works without modification on my system
     
  6. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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    hi etech,
    For ref only, I get the same as alec on my system.
    LTSpice IV with Default Settings in Options,, Win XP Pro, 4Gb PC.

    E
     

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  7. alec_t

    alec_t Well-Known Member Most Helpful Member

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    Interesting. Perhaps the response to the maximum step size setting is processor speed dependent? Wish I was more spice-literate to know what the various settings do :) .
     
  8. eTech

    eTech Active Member

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    Hmmm...Out of curiosity, I reset all my setting to default (they already were set to default), and reran the simulation.
    Still ran ok without modification.

    PC- CPU Q6600, SSD, 3Ghz, Win10, LTspiceIV

    Also tried this on PC - 4.5Ghz, SSD, Win10, LTspiceXVII. Same result...no errors
     
    Last edited: Dec 22, 2016
  9. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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    hi,
    Tried 'alecs' asc file in my Toshiba Satellite Pro laptop, Windows 10, LTS IV, same problem.?
    E
     

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