Ordering LED question

Sorry if I chose the wrong category, but I have no option to choose lighting or LED for the category here.

I am trying to order LED COB, but am confused with the ordering correct LED chip here on this site.
Just to clarify, I am not an E.E. nor E.C. My knowledge is based on purely what the market has been taught me.

I have 24V output driver that I can use. I am trying to develop a table lamp. I need an LED chip(COB) that can use my 24V driver.

One of the filtering options shows Voltage Forward. Is that what I need to look into? I do see many voltage options (from 3V to 48V). I also need to have at least 1000 lumen output or higher(1500lm) with 2700K. Can someone from digikey company help me with my order?
I am just a consumer who does not deal with LED parts every day. I just have no idea what are these parts with extremely delicate codes and descriptions. Please help!


Hi Jason,

Welcome to the community!

It sounds like you have a Constant Voltage power source.

Many COB/Modules need the opposite of that, a Constant Current source.

Some LED strips/modules use Constant Voltage, which means the LED and LED arrays have built in resisters that regulate the amount of current the LED is getting.

For Constant Voltage strips, example PN: COM-12021

It lists the forward voltage of 12V. These are going to be the most common voltages for Constant Voltage LED strips because that is an automotive voltage.

We have some Constant Voltage 24V modules/strips, which would list the Forward Voltage of the LEDs as 24V.

Unfortunately listing 24V doesn’t tell you if it’s a Constant Current or Constant Voltage LED module, you would need to verify in the datasheet to see which it is.

Otherwise, many more LED modules are Constant Current devices, in which case you would need pick your LED module first and then choose your LED driver to fit the Current and Forward Voltage specifications.

Click here for 24V options, check to verify they have resistors if you are using a Constant Voltage source.

Thank you!
I have two more questions. Is the dimension showing the size of the whole plate? or is it the LED diode size?

Second, how is the final lumen output shown?? I see like 400lumenous flux or maximum 600 lumenous flux, but I need total 1000 lumen output from the fixture. How do I know which one actually provides 1000 lumen output or higher?


Also, normally I see that LED fixtures are to meet the voltage, but why all of your products are based on Amperage??

There are two sizes shown on our web site, one is of the Light Emitting Surface, and the other is the physal size of the COB/Module, which would include the substrate the LED or LED array sits on.

Luminous Flux will depend upon if you’re running at a typical(test) current or pushing it to the maximum current, if you’re running at max your LEDs will not last nearly as long and you’re going to need bigger heat sinks. You normally want to run around test current.

Not all led/led arrays are based on amperage. If the module has resistors built in, shown below circled in blue, then you just need to provide the LED array the voltage it is rated for with a Constant Voltage power supply, making sure the current rating (and wattage) exceeds what is needed for the LEDs.

On the other hand, if the LED module does not have built in resistors, the way an LED works is the Forward Voltage is the rating of how much voltage is going to drop across the LED module to power it.

Any power after that will act as an electrical Dead Short meaning it will draw as much current as your power supply can give it until your power supply or LED module dies a smokey death, or both.

LEDs/LED modules are often primarily current driven devices, which means you have to match both current and voltage specifications with the LED Driver chosen based on your LED module.

You would choose an LED Driver whose current drive closely matches the test current of your LED module and has voltage overlap for the rated Forward voltage.