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CRAMF.1
Associate
July 29, 2022
Question

I am planning to use the STEVAL-ILL078V1 board for driving infra-red LEDs. Components will be changed to match values in the attached eDesignSuite printout. Would it be possible to replace "Rlim" with a digital potentiometer to make changes on the fl

  • July 29, 2022
  • 1 reply
  • 876 views
    This topic has been closed for replies.

    1 reply

    Peter BENSCH
    Technical Moderator
    August 8, 2022

    Welcome, @CRAMF.1​, to the community!

    Yes, you can also use a polycrystalline digital potentiometer as a RILIM instead of a fixed resistor. The important thing is that it is a real ohmic resistor and not a semiconductor junction whose behaviour may not be suitable.

    However, please keep an eye on the non-linear characteristic of ISKIP current vs. RILIM, so that you do not overload the IRLED.

    Does it answer your question?

    Regards

    /Peter

    In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.
    CRAMF.1
    CRAMF.1Author
    Associate
    August 9, 2022

    Hi Peter,

    Thank you for confirming. I was waiting for your reply before looking into the details of the resistive properties provided by digital potentiometers. If the latter do not come with ohmic output resistances then I might look at using a 1x8 multiplexer connected to a various resistances. I am currently busy with another project and I may get back to you if I have additional questions regarding the ISKIP parameter you have mentioned below. Thank you for the heads-up!

    Chundra Ramful, P.Eng.

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