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TLC5928 Supply Current vs. R(iref)

Richard Barthel
Intellectual 935 points

Hello All,


On the datasheet for the TLC5928 on page 4 in the electrical characteristics table there are measurements for the supply current with the reference resistor as a test parameter. 

Is there a graph or function to give supply current as a function of the reference resistor. I realize that on page 13 there is an equation for the constant output current as a function of the resistor -- what I am looking for is the current supplied to the device with respect to this component value.


TIA!

-Richard Barthel

Analog Customer Applications Team

 

  • 0
    TI__Guru 65470 points

    Hello Richard,

    When the outputs are off, the current increases typically by 3.5mA changing the resistor from 27 kOhm to 3 kOhm.

    When the outputs are on, the current increases typically by 9mA changing the resistor from 3 kOhm to 1.5 kOhm.

    The supply current of the IC is not just dependent on the reference resistor, but also on the amount of outputs that are on. If you just have 1 output on, the supply current will be different as if you have all outputs on because the drivers for the output transistors consume power. Therefore there is no straightforward relationship between the reference resistor and the supply current of the IC.

    What is the background of your question? Which data of such a graph is most important to you?

    Best regards,
    Brigitte

  • 0 in reply to Brigitte
    TI__Intellectual 935 points

    Thanks for the speedy reply Brigitte. 

    I have a customer asking for this information but I'm not sure why. I suspect this device may go to a mobile application and they are optimizing for power performance. I did ask how many outputs will be on during operation and if that will remain constant -- I'll get back to you when I have more information.

     

    Thanks again for your support.

    -Richard