12V RGB LEDs don't turn off

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NightHawk141
Posts: 1
Joined: Sun Jul 30, 2017 10:58 am

12V RGB LEDs don't turn off

Post by NightHawk141 » Sun Jul 30, 2017 12:00 pm

Hello community.

I have a problem with my TLC5940 Breakout board.
I connection the TLC board to the Arduino Uno as followed
  • VPRG -> GND
    XERR -> Empty
    XLAT -> Pin 9
    BLANK -> Pin 10 and parallel a 10k Pullup to 5V
    SIN -> Pin 11
    SCLK -> Pin 13
    VCC -> 5V from Arduino
    GND -> GND
The Arduino is powered by an USB connector.

Afterwards I put an ordinary LED onto my breadboard and connected the anode to the 5V and the cathode to one of the outputs of the breakout board, just to get familiar with the functionallity. Everything worked fine. Turn on and off the led and dimming as well.
Then I tried to control one of my 12V RGB LED spots. So I connected the 12V from the power supply to the anode of the LED. The RGB wires I connected to the outputs of the TLC5940. I connected the GND of the 12V power supply to the GND of the Arduino.

The Problem is now, that the LED Spot doesn't turn off, even if the output is set to 0. There are still 2mA.
Does the different power sources cause this problem.

I hope someone can give me a hint, how to solve that problem.

Best Regards
NightHawk

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