7 segment decoders

Discussion in 'The Projects Forum' started by RRITESH KAKKAR, Apr 23, 2015.

  1. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    Hello,
    I have done projects with 7447 single chip led display now i want 5 chip display .
    How to this at 12V?
    Is pic micro a best options?
     
  2. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    What are you displaying? Where are the five numbers coming from?
    Can't tell if a PIC Micro a best option unless we know what "best" is measured by.

    A CMOS 4511 is the same function, and has an operating range of 5 - 15 VDC.
     
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  3. Papabravo

    Expert

    Feb 24, 2006
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    The easy answer for doing everything at +12 volts is to use 4000 series CMOS parts. They can work from a Vcc of from +3V to +18V. The LED displays will work from any voltage so long as the current for each segment is limited.

    If you meant something else, then you need to state your questions with more precise descriptions.

    http://www.ti.com/lit/ds/symlink/cd4511b.pdf
     
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  4. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    Hello
    thanks for reply sir
    the PLC controller
    Will display units on it.
    Is any need of bjt switch?
    Why tll 74xxx chip not work in high voltages?
     
  5. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    Hello
    which 5 numbers?
     
  6. ericgibbs

    Senior Member

    Jan 29, 2010
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    You could use either of these two driver IC's
     
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  7. Papabravo

    Expert

    Feb 24, 2006
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    It was never anticipated that 74xxx chips would need to. Since they are based on current sourcing and sinking they would get a great deal hotter if they ran on 12 volts. At 5 volts, some of them could could fry eggs on a summer's day.
     
  8. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    In case of cmos they will not heat?
     
  9. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    Actually, i was doing this with puc micro but it was becomng complicated for 4 digits
     
  10. Papabravo

    Expert

    Feb 24, 2006
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    No. The reason for this is that CMOS chips consume very little power when they are in a stable high or stable low state. There is some power consumption during switching and this is frequency dependent. In a circuit like a 7 segment display they will spend most of their time in a stable state.
     
  11. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Which 5 chips? I took that to mean five digits...
     
  12. WBahn

    Moderator

    Mar 31, 2012
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    Not nearly as much because the current flows that are required are tiny compared to TTL, particularly since standard CMOS has effectively no DC current flow requirements.
     
  13. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    Ok i will check. Today on bread board.
     
  14. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    No only 4 digits
    total 16 wires with gnd with plc for refference so17 wires
     
  15. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    Can't we do this in less wires
     
  16. WBahn

    Moderator

    Mar 31, 2012
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    What is "this"?

    You can do it with just two wires (one signal and ground) if you want by communicating from the PLC to the display using something like CAN or other suitable communications protocol.

    Whether that is a reasonable option is up to you. What is it you are trying to accomplish and what are your constraints?
     
  17. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    Hello,
    my part is in hardware no PLC programming right now.
     
  18. ScottWang

    Moderator

    Aug 23, 2012
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    The LED display circuit using MC14553 and MC14543 on page 7, it can be reach to 6 digits, if you just want 4 digits then you could plus one digit using CD4518 and CD4511.

    MC14553 datasheet.
     
  19. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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  20. RRITESH KAKKAR

    Thread Starter Senior Member

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