LP8556: LP8556SQE-E09 BOOST Output 43V feasibility

Eric201902

Part Number: LP8556

We are using the "LP8556SQE-E09" LED backlight driver on our LED driving board.

We want to use it to drive a light bar configuration that require 43V BOOST Output and 23mA max LED current for each of the 6 channels.

Estimate power: 43V*23mA*6 = 5.93W

According to the datasheet, the "BOOST OUTPUT" range of the IC is 16V to 34.5V:

Questions:

1) If we change the 0x9E and 0xA9 parameters each time during power ON sequence, can we set the BOOST Output Voltage of the IC to 43V?

2) Will we able to update the EEPROM to set the BOOST Output Voltage of the IC to 43V?

3) Is the IC capable of driving 6 channels with BOOST Output Voltage=43V, LED current 23mA/ channel?

over 5 years ago

0 Frank Qiu over 5 years ago

TI__Genius 15776 points

Hardy please help in this case

0 Hardy Wu over 5 years ago

TI__Genius 12915 points

Hi Eric,

1) Yes you can change the value in VBOOST_RANGE and CURRENT_MAX registers every time powering up the device. It is OK for E09 version to support 43V boost voltage.

2) No the EPROM registers is written during manufacture and cannot be changed. Here is one version E05 who have blank EPROM.

3) Yes it is OK. But 43V is already the highest boost voltage the device can support. I suggest you could leave some margin for it.

0 Eric201902 over 5 years ago in reply to Hardy Wu

Prodigy 120 points

Hardy,

Thank you for your response. Yes, today we have tested 42.5V/ 23mA* 6 channels it is working fine. Is there any known durability heating concern we should be aware of?

+1 Hardy Wu over 5 years ago in reply to Eric201902

TI__Genius 12915 points

Hi Eric,

We do not hear any thermal or high temp issue before, since most of the power is not dissipated through LP8556.

Power management

Power management forum

LP8556: LP8556SQE-E09 BOOST Output 43V feasibility