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Stepper Drivers

Discussion in 'Electronic Design' started by Tim Wescott, Aug 13, 2007.

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  1. Tim Wescott

    Tim Wescott Guest

    I've got a client in a bind. He's designed in these parts:
    http://www.interinar.com/stepper driver BSD-02.htm, but the vendor is
    out of stock.

    Does anyone know of replacements I could recommend? The essential specs
    are that it should take step, direction & enable, and be able to drive
    bipolar motors, supply 2A at up to 24 volts. They're running inside an
    instrument, so OEM modules are fine and dandy.

    Thanks.

    --
    Tim Wescott
    Control systems and communications consulting
    http://www.wescottdesign.com

    Need to learn how to apply control theory in your embedded system?
    "Applied Control Theory for Embedded Systems" by Tim Wescott
    Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html
     
  2. Ben Jackson

    Ben Jackson Guest

    I'm sure Geckodrive (.com) has something suitable. They have a huge
    following in the homebrew CNC community[*].

    [*] I'm not sure what your customer will do with all the free magnetic
    geckos they'll get.
     
  3. Joerg

    Joerg Guest

    If Ben's suggestion doesn't pan out and it's urgent give Allegro a call.
    Their app engineers and sales guys should know which of their
    customers sell similar modules. Allegro makes tons of motor driver
    chips. I am not all that fond of them because of noise issues but that's
    another story.

    http://www.allegromicro.com/en/

    1-508-853-5000
     
  4. Zach_G

    Zach_G Guest

    That driver is based on the Allegro A3977:
    http://www.allegromicro.com/en/Products/Part_Numbers/3977/

    If he wants, he could easily design his own PCB's for that driver chip
    with a few current sense resistors and capacitors. If not, xylotex
    makes a driver using the A3977 as well: http://www.xylotex.com/
     
  5. Rich Grise

    Rich Grise Guest

    Make Geico ads? ;-)

    Cheers!
    Rich
     
  6. Jerry Avins

    Jerry Avins Guest

    Is there a size constraint? I could easily do that with a 68HC11, some
    FETs and a suitable power supply; so could you.

    Jerry
     
  7. Joerg

    Joerg Guest

    But they probably need some Monday next week ;-)
     
  8. Tim Wescott

    Tim Wescott Guest

    Precisely. We're buying time to market by putting things together from
    modules as much as possible. At some point in the future we may decide
    on doing something like that as a cost reduction -- for now, being able to
    lash it all together from parts while we concentrate on the really unique
    parts of the system is driving us to purchase things at the highest level
    of integration that we can.

    I'm not sure you could achieve nice microstepping with a 68HC11, but one
    could certainly do it with some of the more modern chips with richer PWM
    resources.

    --
    Tim Wescott
    Control systems and communications consulting
    http://www.wescottdesign.com

    Need to learn how to apply control theory in your embedded system?
    "Applied Control Theory for Embedded Systems" by Tim Wescott
    Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html
     
  9. Tim Wescott

    Tim Wescott Guest

    That looks like a very good candidate -- I'll dig into their data sheet
    soon.

    --
    Tim Wescott
    Control systems and communications consulting
    http://www.wescottdesign.com

    Need to learn how to apply control theory in your embedded system?
    "Applied Control Theory for Embedded Systems" by Tim Wescott
    Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html
     
  10. GMM50

    GMM50 Guest

  11. ["Followup-To:" header set to sci.electronics.design.]
    Speaking of datasheets -- has anybody yet figured out how to find
    datasheets on Allegro's website?

    robert
     
  12. Joerg

    Joerg Guest

    If it's like in the med devices biz the trick is to create some
    universally useful blocks, along with tested avenues for rapid
    prototyping. But that takes time and resources to set up.

    Looks more like an FPGA job. If noise isn't an issue the Allegro chips
    do a fine job. I can't really use them though because the T-off times
    flop around like crazy.
     
  13. Joerg

    Joerg Guest

    What problems do you have? This would be the datasheet for the discussed
    chip:

    http://www.allegromicro.com/en/Products/Part_Numbers/3977/3977.pdf
     
  14. John B

    John B Guest

    Yes.





    Will I tell you?








    Maybe I will.







    Go to the individual product page and on the top right of the page
    there is a column titled "Related links". The datasheet is usually the
    top one in that list.
     
  15. Joerg

    Joerg Guest

    What I really don't like are web sites that assume everyone has a
    wide-screen gaming laptop and you can't scroll all the way to the left.
    Usually I ditch those instantly, assuming that such vendors aren't
    really interested in additional revenue. Hopefully, when their "web
    designers" have run out of popcorn they someplace else to do their damage.
     
  16. What I don't get is why the datasheet is not a big, static link in the upper
    left of any semiconductor product page. It's the one most important piece of
    information anybody might want.

    Web design for a target audience of professionals who know what they're
    looking for is sooo simple. Why is everybody trying so hard to make web
    pages unusable (even starting out from perfectly functional pages)? And semi
    mfgrs still have the best pages of all technical companies -- it gets a lot
    worse when you move to passive and electromechanical stuff, and web pages
    for non-electrical engineering stuff finally hit rock bottom.

    robert
     
  17. Joerg

    Joerg Guest

    My guess it that it's for two reasons. First, some marketing folks make
    the core decisions and they are often disconnected from the customer
    base. Something that is unthinkable in my field of medical devices but
    seems normal in electronics. Often they seem to not even have clue how
    the typical design process works. The other issue is that they hire web
    design firms that consist of a bunch of kids. Those guy really don't
    know anything about the target audience.

    Last but not least the executives in their glass palaces remain
    blissfully unaware of all this despite rather horrendous financial
    results. If things like the 266M loss for NXP don't cause a massive
    wake-up call then I don't know what will. And that isn't new. When Jan
    Timmer delivered his "Chrustchev-style" speech I wrote to him. Did he
    listen? Nope.
     
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