LP8860-Q1: Connecting 10 RGB LEDs in series

Masaru Oinaga

Part Number: LP8860-Q1

Hello, Team,

Our customer is trying to use LP8860BQVFPRQ1 to control RGB LEDs which I_LED is 5 ~ 50mA.

Forward voltage Vf in case of forward current If = 20mA is as follows:
Red: 2.05V
Green: 2.60V
Blue: 2.85V

If we connect 10 LEDs in series, the Vf difference of Red and Blue would be 8V; Would there be an issue such as thermal problem of driver FET getting hot?

Best,
Masaru Oinaga

over 2 years ago

0 Zhiqian Wu over 2 years ago

TI__Mastermind 31365 points

Hi, Masaru

First at all, is it a new design? We recommend to use LP8864/LP8866 in the new design. For independent control, it is better to use LP8863

If the current is 20mA, the additional thermal is 0.16W. It may lead to nearly 5.76 degree temperature increase.

Considering the Green and Blue together, it will contribute nearly 10 degree. thermal shutdown is highly related with the ambient temperature.

0 Masaru Oinaga over 2 years ago in reply to Zhiqian Wu

TI__Expert 4365 points

Hi, Zhiqian,

Thank you for your reply. LP8863 only supports VDDIO and other communication ports with 3.3V and customer is requesting 5V; Therefore, they selected LP8860 instead of LP8863; please correct us if I am misunderstanding something.

Best,
Masaru

+1 Zhiqian Wu over 2 years ago in reply to Masaru Oinaga

TI__Mastermind 31365 points

Hi, Masaru

Understand, you are correct.

Pls let me know if you have any other questions.

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LP8860-Q1: Connecting 10 RGB LEDs in series