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LP8863-Q1: Default Brightness Values at Maximum

Genevieve Pounds

Prodigy 40 points

Part Number: LP8863-Q1

Hi,

The LP8863-Q1's current and brightness values for the LED channel registers are maximum (0xFFFF) by default.

I am currently using the EVM board and an Arduino via I2C but wish to include this driver in a PCB design.

When I power the driver, the LEDs all light up to maximum for a second before the arduino code kicks in to change the brightness values. I wondered if this could be prevented in some way? Perhaps by changing the default max values, or managing the start up sequence?

Many thanks,

Genevieve

0 Patrick Yao 3 months ago

TI__Mastermind 24600 points

Hi Genevieve,

Our expert will give you feedback later.

0 Zhiqian Wu 3 months ago

TI__Mastermind 20955 points

Hi, Genevieve

For this part, could you pls confirm the EN pin and PWM pin before the Arduino code kicks in?

0 Genevieve Pounds 3 months ago in reply to Zhiqian Wu

Prodigy 40 points

Hi Zhiqian, thanks for your response.

The EN pin is tied to VDDIO (pulled up) when the board is powered on. At the moment the PWM pin has no pullup, so to be controlled by the Arduino

0 Patrick Yao 3 months ago in reply to Genevieve Pounds

TI__Mastermind 24600 points

Hi Genevieve,

Our expert will give you feedback later.

0 Zhiqian Wu 3 months ago in reply to Patrick Yao

TI__Mastermind 20955 points

Hi, Genevieve

So pls confirm that the PWM is pulled low during the startup.

0 Genevieve Pounds 3 months ago

Prodigy 40 points

Hi Zhiqian,

The PWM was floating during starting not pulled down, this was the issue! Thankyou.

0 Zhiqian Wu 3 months ago in reply to Genevieve Pounds

TI__Mastermind 20955 points

Hi, Genevieve

Sure, we can close this thread if no other questions.