TLC5941: XERR is always output low

ACGUY

Part Number: TLC5941

Hello E2E,

Our customer is using the TLC5941 for new board.
Their XERR are output Low.
That is not TEF and LOD. We could not find the cause for it.

Condition;
- MODE is Low.
- BLANK is High to Low -> LED on -> XERR is Low.

If you know similar case that please let us know it.

Best regards,
ACGUY

over 6 years ago

0 ACGUY over 6 years ago

Guru 11170 points

XLAT and XERR.pdfHello E2E,

Please see the attached file.
I think that XERR will goes LOW as a result of XLAT high-edge.
Is it correct?
and,
How long time the XERR LOW at fig-12 in datasheet?

Regards,
ACGUY

0 Rosley Ge over 6 years ago in reply to ACGUY

TI__Intellectual 950 points

Hi,
You need to add an external pull-up resistor in this XERR pin. Could you confirm it?
Thanks,
BRs,
Rosley

0 ACGUY over 6 years ago in reply to Rosley Ge

Guru 11170 points

Hi Rosley,

Thank you for reply.
XERR pin has pulled-up on supply.

BR,
ACGUY

0 Kenneth Du over 6 years ago in reply to ACGUY

TI__Genius 14295 points

Hi, ACGUY,

Sorry for the delay and do you solve the problem?

Thanks.
Regards,
Kenneth

0 ACGUY over 6 years ago in reply to Kenneth Du

Guru 11170 points

Hi Kenneth,

Thank you for your concern. We have not solved it yet.

By the way, I have update. OUTn outputs Low after BLANK. Is it normally?

Regards,

ACGUY

TLC9541 OUT is Low.pdf

0 Kenneth Du over 6 years ago in reply to ACGUY

TI__Genius 14295 points

Hi, ACGUY,

Yes, when BLANK = L, OUTn are controlled by grayscale PWM control.

Would you share your code?

Thanks.
Regards,
Kenneth

0 ACGUY over 6 years ago in reply to Kenneth Du

Guru 11170 points

Hi Kenneth,

Is code for MCU? It is customer's. Therefor I can't not attach it to E2E.

Q: OUTn outputs Low after BLANK. Is it normally?
A: Yes, when BLANK = L, OUTn are controlled by grayscale PWM control.

Sorry, I could not understood your comment.
Why is device output Low after BLANK high? LEDs are not disconnected.

Regards,
ACGUY

0 Kenneth Du over 6 years ago in reply to ACGUY

TI__Genius 14295 points

Hi, ACGUY,

Sorry for the misunderstanding.

When BLANK is high, all OUTn outputs are forced OFF. And the output voltage should be high while the output current is low.

Thanks.
Regrads,
Kenneth

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TLC5941: XERR is always output low