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TLC59108: definition of "Constant current"?

Part Number: TLC59108

Team,

I have seen the below E2E post about "constant current":
https://e2e.ti.com/support/power_management/led_driver/f/192/p/149979/542323#542323

Q:Could you please confirm that "constant current" really means that the current on given output (OUTn pins) will be kept constant for a given step?
The datasheet is not very clear. "constant current" seems to be related to the current difference between different outputs:
http://www.ti.com/product/TLC59108/datasheet/application_and_implementation?search=constant,current#SLDS1562956

Q:Is it true as well for the TLC59108F that has open-drain outputs?

Q: Or will the 97kHz PWM will be seen directly on the outputs (OUTn)?
If this is the case this will likely create ripple and could potentially to lead to EMI problems? Any advise to overcome this?

Thanks in advance,

Anthony

  • Hi Anthony,

    Please refer the below comment.

    :Could you please confirm that "constant current" really means that the current on given output (OUTn pins) will be kept constant for a given step?
    The datasheet is not very clear. "constant current" seems to be related to the current difference between different outputs:
    http://www.ti.com/product/TLC59108/datasheet/application_and_implementation?search=constant,current#SLDS1562956

    TLC59108 is Constant Output Current Adjusted Through an External Resistor (10mA to 120mA).

    Q:Is it true as well for the TLC59108F that has open-drain outputs?

    But TLC59108F is not constant device.

    Q: Or will the 97kHz PWM will be seen directly on the outputs (OUTn)?
    If this is the case this will likely create ripple and could potentially to lead to EMI problems? Any advise to overcome this?

    Try to put some cap in output pin will be help.

    Any other problem please let me know.

    Thanks!

    Summer