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TLC5928x maximum LED current

Stephen Hewitson
Intellectual 305 points
Other Parts Discussed in Thread: TLC59282, TLC59284, TLC59281, TLC5927

Hi,

I'm using a TLC59282 and am driving 14 LEDs at 20mA each. I noticed that there was some RF emissions around the 11.5MHz mark around some of the LEDs causing some issues in the design.

The TLC59282 wasn't getting especially warm so I although I was sinking 280mA I didnt think there was an issue. The datasheet is a little bit ambiguous regarding the maximum current sink characteristics as although it says 50mA I didnt know whether this was per LED or in total.

I introduced a rolling bit mask to light all LEDs but at a reduced duty cycle and the 11.5MHz noise disappeared.

I know that TI recommend using the TLC59284 instead but this is not available in the QFN package, and the design is quite space constrained. Alternatively there is the TLC59281 which could work as a replacement.

What is the maximum current that the TLC59282 can sink through the ground pin?

I've read the post under "TLC5927 - Maximum Driving Current for a LED Driver" but I didnt know if it changed going to the TLC59xxx or not.

  • 0
    TI__Intellectual 955 points

     Hello Stephen,

     TLC59282 can sink 45mA current per channel as the maximum in recommended operating condition when VCC is more than 3.6V. If all output are on then, 720mA current flows into GND pin. The abusolute maximum rating of sink current per channel is 50mA. The external resistor value for output current setting should be 1.12Kohm or larger resistor value as value of the external resistor for current setting to avoid exceeding output current.

     Best regards,

     Kazuya Nakai.