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Simulation model for LM3914 Bar/dot display driver

Discussion in 'Circuit Simulation & PCB Design' started by alec_t, Apr 25, 2013.

  1. alec_t

    alec_t Well-Known Member Most Helpful Member

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    I've trawled the net and seen various requests for an LM3914 spice model, but not found a working one.
    So here's one which I've devised which has no bells and whistles but which simulates, to a first order, the main IC functions including:- a) bar/dot mode selection, b) dot mode carry for cascaded ICs, c) resistor-programmed hi/lo reference voltages, d) output current selection, e) non-grounded V- and divider ladder, f) independent V+ and Vled, g) leakage current of outputs, h) segment overlap and i) supply current variation with V+ and Vref output load.
    I'd appreciate a peer review of the model here at ETO prior to my uploading it to the Yahoo LTS user group. Constructive criticism and bug reports welcome.
    Attached are two zip files: LM3914.zip contains a .sub model file, its .sym symbol file and a .asc test jig file. LM3914asc.zip contains similar files for a .asc hierarchical version of the model, in case anyone wants to modify it.
     

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    Last edited: Apr 25, 2013
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  2. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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    hi,
    Thanks 'alec', I will give it a go as soon as I can, will let you know how it goes.

    I did a hierarchical model some time ago for my own use, but I was never satisfied with it enough to release it.

    Yours look like it will get the job done.:)

    Eric
     
  3. alec_t

    alec_t Well-Known Member Most Helpful Member

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    Hi Eric,
    I downloaded your model 'some time ago' when it was still in the early stages, but I think I must have overwritten it at some point. IIRC it included opamps to process the ladder voltages?
     
  4. dave

    Dave New Member

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  5. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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    hi,
    Yes I used comparators, I would say yours is a more elegant solution.

    I have reduced your test_asc to just one LM3914 so that I could put it thru its paces, looks good so far.

    You could use the 'generic' diode from F2 selection and allow the user to change the 'leds' block Vfwd Attribute.

    E.
     

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  6. alec_t

    alec_t Well-Known Member Most Helpful Member

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    Thanks for looking into this.
    I put two instances of the IC in the Test asc so that the dot mode carry between cascaded ICs could be checked easily. Good point re using the generic diode.
     
  7. maiky1024

    maiky1024 New Member

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    Excuse me Alec_t i need to use the component but when I downloaded your file didn't find the .sym file, could you upload this please
     
  8. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Hello, welcome to ETO.

    The SYM file does not have a ".sym" extension, it has a ".asy" extension. All three files are in LM3914.zip:

    LM3914.asy -- This is the sym file
    LM3914.sub -- This is the model file
    LM3914_Test.asc -- This is a simulation file used for testing.
     
  9. alec_t

    alec_t Well-Known Member Most Helpful Member

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    I'd just add that the model was developed for use with LTspice (a free download from Linear Technology), but might need syntax changes to work with other Spice flavours.
     
  10. maiky1024

    maiky1024 New Member

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    umm I think that I must do it by hand, I am current working with NI Multisim, thank you, likewise.
     

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