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TPS61196: Different color LEDs on each string.

Wayne Eckertson
Prodigy 170 points
Part Number: TPS61196

I would like to drive LED strings of different colors.  For example: string 1 would have 10 red LEDs while string 2 would have 10 green LEDs.  Do I need to match up the total Vf of each string to equal the other?  If so, how close do they need to be?  The green and red LEDs both have 20mA current ratings. 

  • 0
    TI__Mastermind 22745 points

    Hi Wayne,

         No, don't worry about the voltage difference, since the different voltage among the IFBx will dorp on the IFBx pin(internal current sinks). But there is one thing that you need to pay more attentation to the "LED Short-Cross Protection Using the FBP Pin", you can refer to datasheet section 7.4.1.3 for detail explainantion. You need to make sure the maximum voltage between 10 RLED and 10GLED will not exceed the "VLED_SHORT" setting. Since usually Red LED has lower forward voltage, may be you can insert some resisitors or diodes to increase the voltage on this string. But you need to do test to verify.

    Regards

    Sean