HTL to TTL conversion..

Discussion in 'General Electronics Chat' started by kunalpowar1203, Mar 8, 2012.

  1. kunalpowar1203

    Thread Starter New Member

    Feb 26, 2012
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    i have to reduce a 0 to 24v HTL based square wave signal whose frequency is upto 30kHz max, to TTL ( 0 to 5v) signal. suggest appropriate method for the same.:confused::)
    Also i need to design a block which does the exact reverse.
     
  2. buzaiandras

    Member

    Jul 18, 2011
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    For the first part maybe you could use a resistive divider.
     
  3. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    For the conversion of TTL to the "HTL" you could use the SN7407 open collector buffers.
    With a resistor from each output to the 24 Volts, you will have your 'HTL" signals.
    A resistor of 4K7 will probably work.

    I have attached the datasheet of this SN7407 for you.

    Bertus
     
  4. crutschow

    Expert

    Mar 14, 2008
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    What is the current capability of the HTL signal and what is the load of the TTL signal?
     
  5. Papabravo

    Expert

    Feb 24, 2006
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    1,786
    LM393 Dual or LM339 Quad Comparator for HTL to TTL conversion. Outputs are Open Collector and will sink several tens of milliamps.

    For the reverse direction I recommend a high side or a low side switching transistor. Depends if your load needs to be grounded or can be floating in the off state.
     
  6. kunalpowar1203

    Thread Starter New Member

    Feb 26, 2012
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    Basically, the HTL signals that i need to convert to ttl are derived from a Rotary incremental encoder. i need to process this signal in a micro controller. and after that. i've to send a copy of the same signal to a motor drive. before i do that, the TTL needs to be converted bak to HTL levels.
     
  7. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    Will the two level converters be at different locations, or can they be together?
     
  8. crutschow

    Expert

    Mar 14, 2008
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    If it's a slow speed signal from a rotary encoder then I think a resistive divider (say 25kΩ and 5kΩ) would work to go from HTL to TTL levels (if going to a CMOS input), and a SN7407 to go back to HTL levels, as bertus suggested.
     
  9. kunalpowar1203

    Thread Starter New Member

    Feb 26, 2012
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    yeah they need to be separate..
     
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