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TLC5941: FET Design for PWM Dimming

Emma Darby
Prodigy 40 points
Part Number: TLC5941

Hi there, I am hoping to use the TLC5941 to power 5 RGB LEDs. The LEDs are used to illuminate a sample for camera vision to see and measure the colours of the sample. Therefore, it is highly important for them to be fed by a constant current for precise camera vision and measurement. I was reading through some of TI's supporting documentation and it says that dimming is either done using via analogue dimming or PWM. The PWM dimming is either configured with main FET, series FET or sunk FET. From the documentation it seems that camera vision may flicker with a main FET. See below for the table in the "Common LED Functions and LED Design Condiserations". Is the FET in the TLC5941 a main FET? I cannot find this information in the datasheet. If it is, do you have any similar drivers to the TLC5941 that has a setires or shunt FET?

Thanks!

  • 0
    TI__Genius 12915 points

    Hi Emma,

    The FET control functions you mentioned is for LED illumination function, which uses an external FET to drive high current through LED, while the driver works as a gate controller. For the analog and PWM dimming, you could refer to LED animation section with below part.

    TLC5941 integrates precise current sink in each output. Analog dimming or called dot correction controls the output peak current while PWM dimming or called grayscale control adjust the output duty cycle.