LED COB PCB design

Thread Starter

martnl

Joined Feb 6, 2020
5
I am working on creating a specialized LED lamp that emits light in a specific spectrum. I have put together a functional prototype, but my limited electrical knowledge resulted in having to use three LED drivers and three in-series circuits. The light source is made up of two LED COBs and around 25 LEDS in three groups of different current. For cooling I am using a PC fan and a heatsink. I have a complete list of the LEDs and their specifications that are required for this project.

I would like to have a more refined prototype by having a PCB designed that only requires one LED driver. However, I have had trouble finding companies that are interested in a small project like mine for the PCB design.

Do you have any suggestions or could you potentially help me out with this? I would greatly appreciate any advice or guidance!
 

MrSalts

Joined Apr 2, 2020
2,767
I am working on creating a specialized LED lamp that emits light in a specific spectrum. I have put together a functional prototype, but my limited electrical knowledge resulted in having to use three LED drivers and three in-series circuits. The light source is made up of two LED COBs and around 25 LEDS in three groups of different current. For cooling I am using a PC fan and a heatsink. I have a complete list of the LEDs and their specifications that are required for this project.

I would like to have a more refined prototype by having a PCB designed that only requires one LED driver. However, I have had trouble finding companies that are interested in a small project like mine for the PCB design.

Do you have any suggestions or could you potentially help me out with this? I would greatly appreciate any advice or guidance!
If you download one of the many Free PCB design software packages and draw your own PCB, you can have 5 to 10 pieces made for about $15-25 including shipping from places like jlcpcb.com or PCBWay.com (both in China). It takes about 3-weeks. You can get them in about a week for double the price. Both companies can mount your parts as well. Prices and time goes up but there are special sales for this service from free to $100 per project so check it out.
 

Thread Starter

martnl

Joined Feb 6, 2020
5
The point is that I know exactly what power each LED should draw, but I have no idea how to power all these LEDs properly (use of resistors? current mirrors?) I tried Altium Designer, but that's way beyond my technical knowledge. So basically, I need someone to design a circuit for me. The costs aren't really an issue
 

BobTPH

Joined Jun 5, 2013
8,765
If you need three different current levels, three is the minimum number of drivers you need.

It sounds like you already have the correct design. Put LEDs needing the same current in series and use s constant current driver for each series string.

Each string will need a voltage that is the sum of all the LEDs in it. Constant current drivers will give a range of voltages they can handle. If the voltage is more than about 100V, you might need to nake two strings and use two drivers for that current.
 
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