Hi,
I’m working on a project that requires about 7 discrete LED’s. I’ve always just used a dropping resistor in previous projects. For this project I wanted to try to use a driver instead. I ended up getting some Diodes Incorporated BCR421UW6-7 linear drivers to test with.

I bread boarded them according to the datasheet with 4 LED’s in series and worked fine. However I had to use about 13-14 volts since the 3.2v LED’s were in series. This is more than what is readily available in the device.

I then tried the same 4 LED’s in parallel. I was able to drive them to the same brightness with 5 volts. Current draw was the same in both configurations.

My question is, is it ok to use the driver with the LED’s in parallel for my application? What would the drawbacks be?

I couldn’t find much online to answer the series/parallel use with really any LED driver.

Thanks

 

Drawbacks for LEDs in parallel:
The datasheet for every LED shows a range of forward voltages. White LEDs usually have a voltage range from 2.8V to 3.6V. You usually cannot order LEDs all with the same forward voltage.
In parallel, the 2.8V LED will be very bright and maybe will burn out and the 3.6V LED will be dim or produce no light.
You can buy hundreds of LEDs, test them all and group them so that the group has LEDs with the same forward voltage.