LP55231: When drive the white LED,the maximum output current is 4ma.

user5952126

Part Number: LP55231

Hi Ti Team,

I used the two pins of the LP55231 to drive a high-bright LED, but the measurement found that the White LED‘s current only has 4ma.I am sure that the brightness has been adjusted to the maximum with the software.The Sch is as follow.What is the matter with it?

over 6 years ago

0 Charles-Chen over 6 years ago

TI__Genius 11836 points

Proper engineer has been assigned to take a look at this and will reply you soon.

0 Kenneth Du over 6 years ago in reply to Charles-Chen

TI__Genius 14295 points

It's OK to use several channels together.

Did you test it with 25.5mA/channel and 100% PWM when you got 4mA?

If so can you remove your R25/R26 and test the current again? Please share your white LED current waveform and anode voltage waveform.

0 user5952126 over 6 years ago in reply to Kenneth Du

Prodigy 70 points

I have removed R25/R26,and the current is 2mA when the white LED 's anode voltage waveform is 100% PWM and the votage is 2.6v.But the type Vf of white LEDs is 3.3v.