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Trying to increase the voltage out of a photodiode.

  1. Oct 12, 2012 #1
    I have an impulse of ~200mV, ~50nA for about 0.15 seconds. To interface with my circuit, I need it to be 1V+. The problem is, I don't want to use an opamp, or something else that needs to be constantly powered. An ideal solution would be a relay or a FET that has a gate threshold in the millivolt range. However, I can't find anything similar to this. I have power available, but I do not want it to be used until the impulse occurs. Are there any other options for me at this low voltage level?
     
  2. jcsd
  3. Oct 12, 2012 #2

    berkeman

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    Staff: Mentor

    The output from a photodiode is a photocurrent. Are you getting that 200mV by putting the 50nA through a 4 MegOhm resistor?

    How often do the pulses occur? Do you need to know the pulse width, or is it okay if you just get a trigger signal for each pulse?

    There are also some very low power opamps that may do what you want...
     
  4. Oct 12, 2012 #3

    berkeman

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    Staff: Mentor

  5. Oct 12, 2012 #4
    Depends upon your application.
    One option might be a charge pump.
     
  6. Oct 12, 2012 #5
    Get a micro power op-amp!!!!
     
  7. Oct 12, 2012 #6

    berkeman

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    Staff: Mentor

    Great minds think alike :biggrin:
     
  8. Oct 12, 2012 #7
    Thanks, I take it as a big compliment.:biggrin:
     
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