Power supply - remote sense

Discussion in 'General Electronics Chat' started by Mad I.D., May 7, 2010.

  1. Mad I.D.

    Thread Starter New Member

    Apr 15, 2010
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    Hi guys.

    I'm developing a power supply with remote sense capability. I don't want to discover hot water again so I would like to see what have people already done on this topic. Unfortunately, I didn't find ANY circuits by Google concerning remote sense.

    If you know some book or site please share.

    Thank you
    Ivan
     
  2. BMorse

    Senior Member

    Sep 26, 2009
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    Remotely sensing what?

    B. Morse
     
  3. beenthere

    Retired Moderator

    Apr 20, 2004
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  4. Mad I.D.

    Thread Starter New Member

    Apr 15, 2010
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    Hi,
    thanks for your reply.
    I already found the site you provided but it gives no information about the actual implementation.

    Well, I will just do the best I can and hope that there isn't a better solution :) Certainly, one or two opamps will be employed only to accomodate remote sensing.

    Answer to the question before: Remote sensing the voltage at the load side so that voltage drop on cable resistance can be alleviated.
     
  5. BMorse

    Senior Member

    Sep 26, 2009
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    That is what I thought you were asking, never know what people are thinking till you ask ;).... Just didn't want to get the wrong assumption.....

    B. Morse
     
  6. SgtWookie

    Expert

    Jul 17, 2007
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    Last edited: May 7, 2010
  7. Mad I.D.

    Thread Starter New Member

    Apr 15, 2010
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    Hi. I'm aware of that. That is the main reason I'm searching for working solutions on the web. Since I have no luck, I'm developing the thing myself. Damping is a major concern in my design.
     
  8. eblc1388

    Senior Member

    Nov 28, 2008
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    One danger of remote voltage sensing is the unlimited rise of output voltage should the feedback signal become lost, due to a break in the feedback wire.

    Under this condition full voltage will be applied to the load and can cause considerable damages.

    The usual way to safeguard this happening is to parallel a diode across the output lines and the feedback lines at the regulated power supply side, or use a 100Ω resistor to replace the diode.
     
  9. nsaspook

    AAC Fanatic!

    Aug 27, 2009
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    Another way to safeguard a runaway power supply is with a crowbar circuit.
    [​IMG]
     
  10. Mad I.D.

    Thread Starter New Member

    Apr 15, 2010
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    Hi, thank you for the diode tip.
    I will apply it definitely. There is a possibility that feedback will be implemented using digital signal processing since that gives me some nice possibilities. In that case diode can be omitted.
     
  11. retched

    AAC Fanatic!

    Dec 5, 2009
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    No, It shouldnt be omitted at all. If there is a uC failure, you will have an issue.

    You want a path based fail-safe. If the feedback line from the UC fails, it must route the power to ground. This is also a good place to add the big RED "Somethings Broke" LED. If the SCR is conducting, light an LED with some of the juice. It will help tell you WHERE the problem occurred.

    By the way, what size PS are you thinking about, and what size loads?
     
  12. eblc1388

    Senior Member

    Nov 28, 2008
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    Sure.

    Try putting one on a power supply with variable output voltage. If you succeed, you might submit the idea to an electronic magazine and get some prize. Been there, done that.
     
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