Led on cout

Theleo De Bruyn 5 years ago updated by Gustav Widén (System support) 4 years ago 3

Hi there

I am using a mc41 for my application, my application is led control with the cout, but is it possible to do this, so my Leds can be dimmed? 

Thank you



IMHO, I don't think you will have much luck doing this.  If you read specs, a the minimum load a COUT will work with properly is 100 mA.  A individual LED only needs 10 mA  at full brightness.  Any current over 20 mA will cause a LED to fail.  You will need a series current limiting resistor as well as a separate load resistor, to be wired in parallel with the LED and current limiting resistor.  And, after you've done this,  you may note that the amount you can vary the brightness is VERY limited.   You should define the output as a PWMout, not COUT, for best results.  

I've been working with IQAN products for 12+ years, so have been there, done this.   I would suggest wiring something up on your bench first to check this out and see if it's acceptable.

Good Luck,


Theleo, did you ever solve this.  Have a similar application


Hi Stefan

I have solved this problem. I have used a PWMout instead of a Cout. It now works prefectly. There is just one tiny thing, the leds will shine a bit. Even when the PWMout is 0%. This is because of the constant measuring for a lost in resistance.

best regards,