TLC5944: How to handle unused output pins.

Jongkap Oh

Intellectual 320 points

Part Number: TLC5944

Hello,

I would like to know how to handle unused output pins of TLC5944.

There is a related thread already and it says "for unused output pins, pull them down to the GND" .

But isn't it detected by the LOD and generate XERR flag continuously?

So, I would like to know how to handle unused output pins properly without any failure flags.

Thanks.

over 4 years ago

0 Charles-Chen over 4 years ago

TI__Genius 11836 points

Hi, Jongkap,

The device only detect open LEDs and short LEDs to GND when the corresponding channel is turned on. Hence, if the unused channels are not turned on, there will not be any failure flags even if you pull unused output pins down to the GND. Please refer to the page 22 of datasheet for details.

0 Jongkap Oh over 4 years ago in reply to Charles-Chen

Intellectual 320 points

Hi Charles,

The "channels are not turned on" means that the channels which has the GS data less than 20h(32d)?

And please let me know the thermal PAD is needed to be tied to GND or not.

Thanks.

0 Charles-Chen over 4 years ago in reply to Jongkap Oh

TI__Genius 11836 points

Hi, Jongkap,

1. You are right. The GS data must be 21h(33d) or more to get the LDO result. However, it is recommended to set the GS data to 00h to completely turn off the channel for unused OUTn.

2. The thermal PAD is needed to be tied to GND.

0 Jongkap Oh over 4 years ago in reply to Charles-Chen

Intellectual 320 points

Hi Charles,

Thank you for your help.

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TLC5944: How to handle unused output pins.