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OPT8241-CDK-EVM with high power IR LED

Eric Chen27
Intellectual 470 points


Hi TI,

I make a board with high power IR LED,

If I want to test IR LED with OPT8241-CDK-EVM by VoxelViewer.

How should I adjust parameter by VoxelViewer?

I adjust modulation frequency(mod_freq1, mod_freq2) to 20MHz.

Do I need to adjust other parameters?

I will appreciate your comment.

Best regards,

Eric

  • 0
    TI__Expert 3800 points
    Eric,

    If you are using high power IR LEDs, you have to make sure that the LEDs don't over heat. The typical peak currents that we use are higher than the maximum average current rating for the LEDs. You would have to start with low current and low integration duty cycle and carefully increase the current levels to make sure no component on the board is burning out.
    You can adjust the integration duty cycle in voxel viewer.

    Regards,
    Subhash
  • 0 in reply to Subhash Chandra Sadhu
    Intellectual 470 points

    Hi Subhash,

    I use "ILLUM_N" to control IR LED, do I need to remove R101 and add resistor to R99?

    If I still use R101(ILLUM_P), is it available?

  • 0 in reply to Eric Chen27
    TI__Intellectual 2030 points
    Hi,

    If you need to use ILLUM_N, your understanding is right. You need to remove R101 and put as R99.
    can you elaborate on your question about ILLUM_P. What are your referring to as "it" when you say "is it available?"?

    Regards
  • 0 in reply to Bharath Patil
    TI__Intellectual 2030 points
    Just one more thing to take care of when you use ILLUM_N, you can set illum_fb_inv='1' to make sure the feedback works similar to the case when you use ILLUM_P. Otherwise, there will be a phase shift of 180 degrees and that will result into a different final phase offset. Phase shift is not a problem as it can be compensated with common phase offset correction, but setting illm_fb_inv='1' makes the configuration simpler.

    Regards