Is this a good way to dim a 5-inch LCD for my Raspberry Pi?

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hopalele74

Joined Dec 15, 2020
2
Hi. I'm trying to make a DPI display to work with my Raspberry Pi.
First, I searched around and found out that the 555 timer IC is a good way to control the brightness of the display. And since the background LEDs needs around 23V to function, I've included a step up converter.
It's for a LCD like this one: https://www.adafruit.com/product/1680

But then someone recommended me to use a LED controller instead. Is it a better choice? And if so, what IC would fit this project? That has both dimming and boosting function.

I'm a beginner and this is my first schematic design. So I'm open to any kind of feedback you might have.
Thank you.


Schematic_screen_2020-12-13_04-23-44.png
 

ronsimpson

Joined Oct 7, 2019
1,230
but the backlight requires a constant-current mode boost converter that can go as high as 24V
I do not have a dats sheet for the display. We need to know how much current!
Replace U1 & Q1 with this. It will hold the LED current constant. You have 5V power on the Pi. The 555 will do the same dim thing it was doing.
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