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TPS92391: Driving different LED strings per each channel

Toto Cho
Prodigy 20 points
Part Number: TPS92391

Hello,

I know TPS92391 is a backlight boost LED driver, but I need some special configuration with 6 different LED strings which have different number of LEDs.

For example, CH2 will have 4 LEDs in series, and Vf will be 9.6V.

CH1, 3, 4, 6 will have 2 LEDs in series, and Vf will be only 4.8V.

CH5 will have 3 LEDs in series, and Vf will be only 7.2V.

The main reason that they have different numbers are they have different wavelength for special purpose.

I would like to know if we can have wide range of difference of forward voltage.

If it's not possible, then I may what will be the maximum difference of forward voltage between channels?

Should it be less than 1 or 2V?

Thank you.

  • 0
    TI__Mastermind 30990 points

    Hi Toto,

    TPS92391 has a V_LEDSHORT of typical 5.4V, if any channel voltage over this threshold, the related channel will be treated as LED short so that will be removed from operation. So I am afraid that your working condition might have such issue since voltage deviation between CH1,3,4,6 and CH2 is near this threshold.

    BR

    Patrick