TLC5947: The Outputs are always 0

Pengcheng Liu

Part Number: TLC5947

Hi, I am using TLC5947 to drive multiple LEDs in my project. I have been playing with it for a while, but the channel's output is kept 0. I am not sure where is my problem, any help is appreciated. The BLANK pin is connected to GND, Vcc is connected to 3.3v source, and other operations have been shown below. I tried to write GS[18-20] (Chanel18-20) to 0xFFF.

over 5 years ago

0 Kenneth Du over 5 years ago

TI__Genius 14295 points

From the figure, it seems that it meets the following requirements:

You can try to send all channels with 0xFFF to see the effect.

We also suggest you can control your BLANK pin since it can reset the GS counter.

Please also refer to our sample code:

Vers2_TLC5947_MSP_EXP432P401R_nortos_ccs.zip

0 Pengcheng Liu over 5 years ago in reply to Kenneth Du

Intellectual 590 points

Hi Kenneth, Thank you very much for your reply. It works after I change LED from common cathode to common anode. Is it because of my internal reference resistor is too large? I want my design works on common cathode LED.

Thank you very much,

0 Charles-Chen over 5 years ago in reply to Pengcheng Liu

TI__Genius 11836 points

Hi, Pengchen,

The TLC5947 is constant-current sink output. So it should be used in common anode.

0 Pengcheng Liu over 5 years ago in reply to Charles-Chen

Intellectual 590 points

Hi Charles,

thank you very much for your reminder, it helps.

Pengcheng.

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TLC5947: The Outputs are always 0