LP5012: LEDs do not light but can communicate over I2C

Anton Nikitin

Part Number: LP5012

Hello lovely people,

I have an LP5012 on my PCB (attached layout), and I'm having an issue with getting the LEDs to light. I can confirm I can write/read-back registers.

I'm also wondering, when I power on the PCB I can read a voltage of around 1.2-2V on each of the OUT channels, is this normal? (Before CHIP_EN has been written to).

Thanks,

Anton

over 4 years ago

0 Monet Xu over 4 years ago

TI__Genius 9255 points

Hi,

What is the value of VLED that you use and what about the forward voltage of LEDs?

Monet Xu

0 Anton Nikitin over 4 years ago in reply to Monet Xu

Prodigy 10 points

Hi Monet,

Thanks for your reply. V_LED is 3.3V and the forward voltage of the LEDs are as follows:

Here is the schematic for the LED buttons I'm using:

0 Monet Xu over 4 years ago in reply to Anton Nikitin

TI__Genius 9255 points

Hi Anton,

please increase the voltage of VLED up to at least 4V. then try again.

Monet Xu

0 Anton Nikitin over 4 years ago in reply to Monet Xu

Prodigy 10 points

Hi Monet,

Thanks for the reply - I'll give that a try.

Just wondering, on the output of the OUT channels when the chip is off, what voltage should I read on them by default?

Thanks.

0 Monet Xu over 4 years ago in reply to Anton Nikitin

TI__Genius 9255 points

Hi Anton,

on the output of the OUT channels when the chip off, the voltage will be lower than the VLED.

Monet Xu

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LP5012: LEDs do not light but can communicate over I2C