How I can increase current

Discussion in 'General Electronics Chat' started by murock, Jan 9, 2014.

  1. murock

    Thread Starter New Member

    Jan 9, 2014
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    I current have 3.6mA going down a wire, but I need to get up to 5A to drive a large device. I've heard I can use drivers to do this. I came across a Darlington Array but I'm not sure I how to implement this. Any ideas or suggestions of where to look would be great.
     
  2. MikeML

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    Oct 2, 2009
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    What is the supply voltage for the high current load? (Where does the 5A come from?)
    What is load resistance? (Or what is the load?)
     
  3. murock

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    Jan 9, 2014
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  4. MikeML

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    Your link requires a log in.

    I still need the igniter voltage when 5A is flowing through it?
     
  5. MikeML

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    Actually, now that I have seen the schematic, you need a voltage controlled switch, like an NMOS transistor. Presumably, you want current to flow through the igniter when the output pin of IC6b is high?
     
  6. murock

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    Jan 9, 2014
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    Yes thats exactly what I need
     
  7. murock

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    Jan 9, 2014
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    How would I wire one to get 5A through the igniter?
     
  8. murock

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    Jan 9, 2014
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  9. MikeML

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    What NFET did you use?

    Something wrong with your modified schematic. With 20V to the igniter, if it takes 5A, its internal effective resistance would be R=E/I=20/5=4Ω.

    Your 1Ω would draw I=E/R=20/1=20Ω.
     
  10. 4pyros

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    Jan 3, 2014
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    Mike I think you have a typo, should 20 ohms be 20 amps?
     
  11. 4pyros

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    Jan 3, 2014
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    Looking at the data sheet for the DR9020 igniter the resistance is 0.65 - 0.9 ohms.
    The typical all fire current is 5 amps. This could be more or less.
    You need to remember the igniter is almost a dead short so most firing systems use drivers that can handle at least twice the current needed for all fire. Also igniters can short out after they are used so you should plan accordingly.
     
  12. MikeML

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    Yep. Sounds like you know more about igniters. Can you suggest a driver circuit that he can trigger from a 9V CMOS gate?
     
  13. murock

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    Jan 9, 2014
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    It just says its an ideal N type MOSFET.
    Even if I remove the resistor I still get a smaller current than I need of 400mA which doesn't change even if I up the voltage.
    http://imgur.com/MTOCrpZ
     
  14. murock

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    Jan 9, 2014
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