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 fly?

[Peter BENSCH]

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

[CRAMF.1]

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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