Output from 6N135

Discussion in 'The Projects Forum' started by hbklau, Jan 11, 2010.

  1. hbklau

    Thread Starter New Member

    Nov 4, 2009
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    Hi all,

    I have some questions here. I am using a optocoupler 6N135 ad the input is from a PWM. However, according to the datasheet, the output of the optocoupler is not exactly the same as the input (inverted output). What i need is the same as the input. I had connected as what the example had shown. Any idea how i can do that?

    Below is the link of the optocoupler <snip>
     
    Last edited by a moderator: Jan 11, 2010
  2. SgtWookie

    Expert

    Jul 17, 2007
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    Please don't post links to sites where people have to sign up to view something; it limits your input and frustrates your would-be helpers. Attach the file using the "Go Advanced" and "Manage Attachments" buttons.

    If you wish to invert the behavior of the opto, use an NPN transistor (with a suitable base resistor) with the emitter grounded, collector sinking current from the opto's emitter, between the two.
     
  3. hbklau

    Thread Starter New Member

    Nov 4, 2009
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    THanks Sir. Will note the attachment issue. I will test out the circuit. Thanks again.
     
  4. hbklau

    Thread Starter New Member

    Nov 4, 2009
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    0
    Hi sir,

    is this the connection what you are referring to? Pls advise. Thanks.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
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    What you posted is not a connection; it is merely a datasheet for the component that you were asking about.

    However, if you connect the emitter side like I suggested, keeping in mind the specifications of the emitter and limitations of base current for the driver transistor, you might be able to get it to work.
     
  6. hbklau

    Thread Starter New Member

    Nov 4, 2009
    9
    0
    Hi sir,

    pls kindly advise whether will the following connection work? I intend to connect the BJT to the Base to act as a switch. So when the BJT is closed, the output is short to ground and if opened, the output will be 5V.

    Next, is it possible to connect a inverter (logic gate) to the Vout of the optocoupler instead? That would simplify the circuit and the generated output will be used as a switching for the Mosfet of Dc converter. THanks.
     
    • opto.pdf
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  7. SgtWookie

    Expert

    Jul 17, 2007
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    Try it like this:

    [​IMG]

    The resistor on pin 7 may or may not be needed.

    You should use a driver IC for your MOSFET gate.
     
  8. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    That's still inverting. It will be noninverting if you connect the load resistor between the emitter and GND, and connect the collector to +5V.
     
  9. SgtWookie

    Expert

    Jul 17, 2007
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    Ron_H,
    In the original schematic, the emitter's cathode was grounded via Rm, and the PWM signal was supplied to the anode.

    I simply moved Rm to the anode, connected it to +5v, and placed the input PWM signal on the cathode.

    It was just an easy way to keep the logic positive without adding any components.
    [eta]
    excerpted original schematic from Agilent's datasheet:

    [​IMG]
     
  10. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    I missed your change.:(
     
  11. SgtWookie

    Expert

    Jul 17, 2007
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    It was an easy-to-miss change.

    I should've posted the original along with the suggested modification.
     
  12. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    You're too kind.:)
     
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