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TLC5791 - Number of LEDs in series driven by each channel

Sharath Prasad1
Prodigy 20 points

I am using TLC5971 for Driving RGB LED strips as Light Ring with perimeter of 200mm for Dimming and Alarm/Status Application. For my design requirement ,i have to drive atleast 12 LEDS in series per channel. This 12 LED series current (either R/G/B) will be around 58mA ( Current Limiting resistor set not exceed 60mA/Channel)

The application circuit 3 in datasheet shows only three LEDs in series and One LED as optional. Is that maximum 4 LEDs in series i can drive?

Can I use internal regulator as application for driving my design requirement. 

There is note in datasheet  mentioning Number of series LEDS depends on VCC?

Can you please explain in detail these constraints and share design calculations /recommendations for using Number of LEDs in series per channel.

Thanks

Sharath

  • 0
    TI__Expert 3275 points

    Hi Sharath,

    There is no limitation of driving LEDs per Channel, the problem is you need to make sure max voltage on OUTx couldn't exceed 17V.

    In that case, you have to carefully choose your VLED, and make sure the max voltage on OUTx < 17V even in transient.

    For internal regulator, of course you can use it.

    Best regards,

    Feifei