LP55231: Unexpected current consumption

yiger

Part Number: LP55231

Hi there,

I am developing an RGB LED Driver circuit as shown below. Although I am expecting each LED to drain 20mA, the first LED drains 160mA where each additional LED drai 20mA more.

On the other hand, when I test the following breakout board, all looks fine, each LED drain 20mA as expected.

www.sparkfun.com/.../13884

Could you please let me know if I am doing something wrong?

over 6 years ago

0 Kenneth Du over 6 years ago

TI__Genius 14295 points

Hi,

As you know, LP55231 can only output 25.5-mA for each channel, so it seems there's some problem for your first LED channels.

So would you first to double confirm if it's OK by replacing the chip for a new one?

The schematic is good and actually you can leave INT unconnected if not used.

Suggest you also refer to our EVM:
www.ti.com/.../snvu214b.pdf

Please let me know if this solves your problem.
Thanks.
Regards,
Kenneth

0 yiger over 6 years ago in reply to Kenneth Du

Prodigy 30 points

Hi Kenneth,

I replaced the chip multiple times, I am sure it is not related to the chip itself. However I just noticed that C1+ C1- C2+ C2- connections are correct in my schematic. May it be the reason?

0 Kenneth Du over 6 years ago in reply to yiger

TI__Genius 14295 points

Hi,

Ops, yes, you need to change them first.

Sorry for missing that.

Please connect C1+/C1- and C2+/C2- correctly.

Kenneth

0 yiger over 6 years ago in reply to Kenneth Du

Prodigy 30 points

Yes, this seems to solve the issue. Thanks for the support.

Regards

0 Kenneth Du over 6 years ago in reply to yiger

TI__Genius 14295 points

Great.

Would you help to click "Reslove"?

Thanks.
Kenneth

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LP55231: Unexpected current consumption