Need help driving 36V LED - Page 1
Forum section: electronics / beginners

author: Undweeber
author_rank: Regular Contributor
timestamp: May 30, 2020, 04:56:54 pm
content: First of all, here is the data sheethttps://download.luminus.com/datasheets/Luminus_CXM-27_GEN1_Datasheet.pdfMy exact LED is 2700K and 95CRI and I am very confused.CXM-27-27-95-36-AA00-F2-21. It’s listed as 36V LED, and at 1.8-2A it’s around 60W, but I’m not sure if it’s constant current or constant voltage and what it means.2. I don’t want to run it at 60W mainly because I don’t want up deal with so much heat, and bulky radiators, that said I will run it with a small radiator.3. I would like it to be dimmable so I’d like to know which aspect can I use to dim it, can I control the voltage up and down or Does it require the current to control the brightness?I REALLY don’t want the PWM flicker, this is one huge dealbreaker for me.. the seller still hasn’t shipped it, ideally I would get a 12V LED and slap a regular constant 1A power supply on it, but these are 36V and I don’t know where to begin.If it requires 36V to run then I would like to run it at 0.5-1A, I don’t want to run it anywhere close to 2A. If to control brightness I must use PWM then which power supply will have a very high frequency non flickering one? Or could I just drive it with 0.5A 36V power supply without dimming?

author: Undweeber
author_rank: Regular Contributor
timestamp: May 30, 2020, 06:44:10 pm
content: I found this unithttps://www.ebay.com/itm/adjustable-power-supply-chargers-DC-1-36V-AC100-240V-Converter-adapter-switching/254270142462?hash=item3b33ae77fe:m:m1CC91HyhPCxtTPItlB3abQIt is variable 24-36V and constant 2A, will it work with this LED?

author: Marco
author_rank: Super Contributor
timestamp: May 30, 2020, 07:04:16 pm
content: Nah, you want a CC power supply.Hard to go wrong with Mean Well. They've got a shit ton of different models, you'll want a ~1A model which has an output voltage range around 36V ... the subset you want will be mostly determined how you want to dim it. Some can be dimmed with a potentiometer, some want a 0-10V or PWM signal, some have DALI.

author: Undweeber
author_rank: Regular Contributor
timestamp: May 30, 2020, 08:10:52 pm
content: isn't that a constant current? its rated for 1A and has variable voltage

author: Marco
author_rank: Super Contributor
timestamp: May 30, 2020, 08:17:28 pm
content: Quote from: Undweeber on May 30, 2020, 08:10:52 pmNo, it isn't.

author: Undweeber
author_rank: Regular Contributor
timestamp: May 30, 2020, 09:04:29 pm
content: why is it not, it has variable voltage and doesn't put out more than 1A, please help me understand, I never met this kind of problem before, and while the terminology seems logical, I seem to be missing something.What is exactly the issue with the linked power supply? I cant find a single CC AC to DC that could put out 36V and be dimmable, i went on MeanWell and cant seem to understand which one would work...thanks for helping..can i install an inline potentiometer to control the brightness in the CC setup? will it control the current? what do you mean by the word subset?

author: Marco
author_rank: Super Contributor
timestamp: May 30, 2020, 09:39:26 pm
content: Quote from: Undweeber on May 30, 2020, 09:04:29 pmIt's not designed to be CC, you have no idea how it's current limit works. It's not like it has a datasheet, or a known manufacturer. it could just be thermal protection or fold back, or anything. It's a variable voltage power supply, even if it has a decent steady current limiting trying to dim it by adjusting voltage is not stable (because at that point it will no longer be current limiting).Mean Well HLG-40H-42 for instance can have it's current limit adjusted with a potentiometer and will drive your LED.PS. also the Mean Well is far less likely to burn your house down.

author: Undweeber
author_rank: Regular Contributor
timestamp: May 30, 2020, 09:45:36 pm
content: what does 0-10V dimming mean? I found this thinghttps://www.ebay.com/itm/ERP-ERM060W-1750-40-dimmable-constant-current-LED-driver-60w-1750mA-40Vdc/233049066057?epid=1625576&hash=item3642ce8a49:g:JbMAAOSwpLdcFdtXits a bit too much power than I need but I would just have to be careful with itMean Well is a bit too expensive.. and it says it has no dimmer on the page.

author: Marco
author_rank: Super Contributor
timestamp: May 30, 2020, 09:56:15 pm
content: Quote from: Undweeber on May 30, 2020, 09:45:36 pmIt means it expects a 0-10V signal to determine the current for the LED, practically this will probably mean you want to buy a 0-10V dimmer switch.Ignoring that, it does look like a decent power supply for your LED.QuoteWebsites are shite, what else is new. Just read the datasheet instead. It allows PWM dimming, 0-10V dimming and potentiometer dimming.PS. even at 1A the LED will need a heatsink BTW.

author: Undweeber
author_rank: Regular Contributor
timestamp: May 30, 2020, 10:24:48 pm
content: thank you again, I know it will need a heat-sinkas per dimmer itself, how does it interface with the driver, I am very much wishing i just go 12V, but the issue is that good quality LED's seem to come at higher voltages, and this is proving to be such a pain in the asscan you suggest on how to dim? is it like a separate module that plugs into the dimmer wires?

author: Marco
author_rank: Super Contributor
timestamp: May 30, 2020, 10:45:42 pm
content: Quote from: Undweeber on May 30, 2020, 10:24:48 pmYes.https://www.amazon.com/0-10v-dimmer/s?k=0-10v+dimmer

author: Marco
author_rank: Super Contributor
timestamp: May 30, 2020, 11:14:15 pm
content: Actually, the datasheet says you can dim the ERP power supply with a resistor/potentiometer too.https://www.erp-power.com/wp-content/series-assets/erm-series/datasheet-long/erm-series-datasheet.pdfA 10K potentiometer is not as pretty as a wall dimmer switch, but a lot cheaper.