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Photodiode Measurement / Current Sensor IC

Johannes Schlothauer
Prodigy 30 points
Other Parts Discussed in Thread: TIPD176, IVC102, DDC112, DDC118

Hey guys,

i'm new in this community, so please be patient with me :)

I want to measure the output current of a photodiode.

Now i'm looking for a current sensor IC, which is capable for the output of some nanoamps.

The photodiode has a µm surface and is amplified over a difference amp. The output is mirrored by the factor 12.

I don't know the exact current range yet. This is why I'm looking for an Inputcurrent of 1-100nA.

Regards

J.S.

  • 0
    TI__Genius 17777 points

    Take a look at the reference design in the link below.  It covers the most common photodiode measurement configuration.  Let us know if this helps, or if you need additional guidance.

    Art

    http://www.ti.com/tool/tipd176

     

  • 0
    TI__Genius 14825 points

    Johannes,

    I agree with Art's recommendation for the TIPD176.  Starting there is great.


    I also think you might look into the DDCxxx family of products, if you want a digital output.  The DDC products are designed specifically for photodiode integration.  The DDC112 is a two channel device that has a fairly variable gain; it measures charge by integrating current over time.    If you want an analog output, the TIPD176 is a great resource, and based on the application requirements, possibly the IVC102.

  • 0 in reply to Jason Bridgmon
    TI__Guru 61380 points
    Johannes,

    I support the DDC products now and can help you if you would like more information!

    Regards,

    -Adam Sidelsky
  • 0 in reply to Adam Sidelsky
    Prodigy 30 points
    Hey Adam,

    I think the DDC118 Octal Current-Input could be a good IC for me, because my chip has 8 Photodiodes integrated.
    The thing I didn't understand is the clockwise digital output. Each input could be shown, but not at the same time?

    At the end I need the characteristic lines of each diode. Is it possible to do this with the DDC118?

    And I'm not sure if the range -500µA to 500µA is enough for me.


    Regards

    J.S.
  • 0 in reply to Johannes Schlothauer
    TI__Guru 61380 points
    J.S,

    Clockwise output? Do you mean Serial output? If so, then this device only supports serial output so you will need to capture all serial data and decode it for your purpose. As for the characteristic lines of each diode, the DDC just reports the charge collected by integrating the current for the specified time you set the CONV period. I'm not sure this is what you are looking for. Most of the DDCs are very low input so you might need to move to a higher current device.

    Regards,

    -Adam
  • 0 in reply to Adam Sidelsky
    Prodigy 30 points

    Thank you for your fast response.

    I've now simulated the current values. 6µA (at ~10Lux) to 160µA(at ~100Lux) output. Do you maybe have IC's, without coding and decoding?

    Simple Current Sensor IC's with Voltage as output.

    Else I'll try to solve it with impedance converters or simple shunt resistors.

    regards

    J.S.