How to Drive High Power LEDs With A DC-DC Adjustable Step-Down Module

High Power Light Emitting Diodes have different requirements that need to be met when compared to regular LEDs. This guide will provide all the knowledge to power whatever High Powered LED you come across but will focus on 3W Aluminum Backed Star LEDs.
Full Article (STL files found here) - core-electronics.com.au/guide...
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In this video I will power a single 3W Led and then 4 of these LED nodes in series. We will figure out and select the right gauge of wire, manage heat dissipation and the power requirements using the Datasheets. This way we can select the correct electrical componentry. LEDs are incredible pieces of modern technology, the real unsung heroes in our electronics world, but they do need to be utilised correctly to take advantage of not only their incredible brightness but their long lifespan as well.
LEDs are unlike other traditional incandescent lights where higher voltages produce brighter light. The amount of light (Lumens) an LED emits depends on how much current is supplied. High-power LEDs can commonly take currents from 350mA to 3000mA. Too much current will result in thermal runaway and broken LEDs. Now most power supplies are made to regulate voltage, not current. If you connected a standard DC voltage regulated power supply to a line of LEDs it would provide too much current to the LEDs and cause them to break. Just remember that LEDs are greedy for current and need somebody to supervise them otherwise they will become gluttons and die a very early life. This is why we need a Constant Current LED Driver between the DC power supply and the LEDs. This acts as the supervisor. The LED driver can regulate the current and voltage provided to the LEDs so that they are always at the perfect level.
A buck-boost converter is a type of DC-to-DC converter that has an output voltage magnitude that is either greater than or less than the input voltage. The technology of buck, boost, and buck-boost (Step Down or Step Up) converters are utilized around the world to provide regulated low-voltage DC/DC power in nearly every electronics market. Importantly these devices manage and prevent excess current flow. If the voltage and current from the chosen power supply are too high for the LEDs you will need a buck (step-down) converter. If voltage and current from the power supply are too low for the LEDs you will need a boost (step-up) converter.
If you have any questions about this content or want to share a project you're working on head over to our maker forum, we are full time makers and here to help - coreelec.io/forum
Core Electronics is located in the heart of Newcastle, Australia. We're powered by makers, for makers. Drop by if you are looking for:
LED - 3W Aluminum PCB (5 Pack, Red) (used here): core-electronics.com.au/catal...
DC-DC Adjustable Step-down Module 5A 75W (used here): core-electronics.com.au/catal...
Ultra Bright 3 Watt Chainable NeoPixel LED - WS2811 (A No Solder Solution!): core-electronics.com.au/catal...
Triple Output High Power RGB LED (9W!) - core-electronics.com.au/catal...
Raspberry Pi Heatsinks (used here): core-electronics.com.au/catal...
12V DC 2A Fixed 2.1mm Tip Appliance Plugpack (used here): core-electronics.com.au/catal...
DC Barrel Jack Adapter - Female (used here): core-electronics.com.au/catal...
18AWG High Temperature Resistant Silicone Wire: core-electronics.com.au/catal...
Artech Digital Multimeter - core-electronics.com.au/catal...
0:00 Intro
0:43 Powering LED Overview
1:07 Video Details
1:48 What You Need
2:40 More Current = More Lumens (Up to a point)
3:02 Why a LED Driver?
3:36 Adjusting the LED Driver Output
5:37 Choosing Power Supply
6:04 Choosing Wire Gauge
6:40 One 3W LED System Setup
7:42 First Pay-off!
7:56 Four 3W LED System Setup
10:04 Second Pay-off!
10:17 Where to Now
11:06 Outro

[@PeterAMann-jf9fx]

One of the finest educators in electronics I have known; well planned and delivered. Kudos :)

[@Core-Electronics]

Huge thanks! 😊 I am in a very lucky position.

[@ettilapse]

Man, every time I need some tips on my tech experiments, I find you every time. Appreciate you and your work man. Thank you.

[@teammouse]

You deserve a lot more likes! Best explanation yet, thank you!

[@Core-Electronics]

Nawww thank you! Share the video with all your friends who need some Bright Lights in their life to help ❤️

[@KingBhakaTV2Tamzo-ix1gh]

In deed

[@khalid_works]

Simple, Informative & Clear. Thank you a lot for make this video. You make connect high power led easy for me specially I want to avoid cheap led drivers and resistors.

[@Core-Electronics]

My pleasure mate 😊 and thanks for leaving such a rad comment.

[@ElLenadorLA]

You may have just solved a problem that’s been wracking my brain! Thank you!

[@vladimirjosifovski9681]

At the end of your presentation, you mentioned that we can use microcontroller to dim those high power leds. Do you have any project describing details how to connect microcontroller to DC-DC controller ? (not led stripes, I need to dim high power leds)

[@timpage5021]

Very clear and concise

[@alemleandro]

You are fantastic! Keep on this way!

[@justinwright9253]

Beautiful explanation! Thank you!!

[@Core-Electronics]

😊😊

[@Prasanna_Naik]

This is really amazing. I really feel this channel videos are highly underrated. You deserve more likes, views and comments brother. Also please make a video on Waveshare Sim 7600G-H use with RaspberryPi running Openwrt. I have commented the same on your Sim7600G-H video.

[@Core-Electronics]

Thank you mate! I have added that great idea to the list 😊

[@ddistrbd1]

good video , I wish you also showed 5 led beads connected in parallel.

[@Shenzhenottimatechnologycoltd]

You are welcome to test our LED driver products

[@rjbiz3639]

Thank you for the video.

[@Core-Electronics]

All good mate! Hope it helped you 😊

[@BushCampingTools]

Great video u have another subber.

[@austingodbey]

Could you add a PWM dimmer into this to achieve dimming? If so would that go before or after the step down module? Thank you, great video!

[@caloigarcia5225]

vEry well explainEd sir..thAnk fOr thE knOwledge

[@Core-Electronics]

yOu're wElcome 😀

[@bluebirdfan100]

superb

[@ianadams5]

Very helpful, thanks for walking us through this! I looked everywhere trying to figure out how to light some cob leds I recently got, but your step by step video explained it very well. I was wondering though, I'm trying to build an infrared illuminator from some 3 watt 850nm cobs I got, but the listing didn't mention what voltage they are, only that they recommended 600 milliamps for the current. How do I figure out the voltage requirement? I read you can use the diode mode on a multimeter to read the voltage on a led, but it didn't seem to work on mine.

[@Core-Electronics]

Surprising to me that there is no indication of recommended voltage but its going to be a 5V. Watts = Amps * Voltage They provided two stats, the Watts (3) and the Amps (600mA = 0.6 Amps). So we end up with: Voltage = Watts / Amps = 3 / .6 Voltage = 5V Hope that helps mate, here is a guide on what I've done here too 😊 core-electronics.com.au/guides/analogue-electronics/ohms-law-practical-examples-for-makers/

[@ianadams5]

@@Core-Electronics Hey thanks for the information, that's what I thought too and what I was going to assume for my illuminator, but I messaged the seller and they messaged me back now and actually said that the voltage was 1.3-1.5V and that the current was 700mA (contradicting their own listing) I also ordered some 395nm UV and white cobs for separate illuminators, and the seller said the voltages for those were 3.2-3.6V and 3.2-3.8V, and all were 700mA at 3W. So I'm even more confused lol. What information do I go off of, the listing or what the seller says? I've looked around and saw other cobs with widely varying voltages and currents in their data sheets and it seems like they're also contradictive too. I guess I'll just have to test (or sacrifice) them with the different voltages. Not sure if I can use links, so in case you're curious, the seller is Cleiscry on Amazon.

[@Core-Electronics]

Contradictory information is the worst mate! When your testing do the lower voltages first and power them only for a couple of seconds. Also make sure your supply device is a constant current driver. I hope all the best for you!

[@tishinpadilla100]

Cool!

[@joshuamittie791]

I'm wondering I bought led headlights they say input voltage is 12 to 36 volts and thought I could buy a couple boost converter and turn up voltage for brighter lights for offroad and track night use . Not sure how it works exactly. No problem soldering and I could pot them in epoxy to waterproof. So if anyone can give advice perhaps a link to what I'm looking for . Thank you for the video

[@smarttrandallrandall4461]

MUY BUENO TUS VIDEOS SORPRENDENTE

[@Core-Electronics]

Muchas gracias mi amigo lejano

[@michealwardle6526]

I'd love a link to the driver step down please and thank you for your time

[@mynameisben123]

Is the back of the LED boards part of the LED? In other words does connecting them all to the heat sink short then together ?

[@Bruhwhat99]

Hi i wanted to use the same setuo but i wonder if i connect in parallel instead the led and instead of increasing the voltage that i increace the ampere... will that work or ruin the leds? So if i want 5 led of 700ma then that i give 3.5A due to i need to connect them that way for a project

[@brendanlenane2685]

Could you wire one of those leds straight to a usb cable to power it. Or would you still need something between

[@kbssaprodussoes]

Why when we wire two 12v 30w white leds in series, the power supply is regulated to 24v and 3 amps, why does the voltage across the leds drops to 18w while running? should we match the voltage to specs or they are already at their max capacity?

[@robertroe1956]

Great video but some questions. The buck converter is pre-set to 750ma by directly shorting the meter across the output. It would be interesting to see what the actual current draw is, both with one and five LED's.

[@russellmartynzutic602]

I found running 4 in series at .5 amp (set by shorting the 2 terminals ) when the current was measured in series not shorting it was pulling .25 amps. Trying to figure out now if I should adjust back up to .5 amps with this method.

[@arthurpillart3789]

For school project i need to power 6m of RGB LEDSTRIP 60watt and 24v what type of led drive should i use and how do i connect it to my arduino?

[@PiyathPamuditha]

Is there any RGB 3W high output LEDs which could change color by using WLED?

[@Hobypyrocom]

great video, but how to connect the microcontroller with the step down buck converter? should you use mosfets? how to wire them in practical environment, where leds will need long power cables, should you add the converter on the powering side or the led side of the cables? how to calculate and compensate for the resistance and losses of long powering cables for the led's?

[@Core-Electronics]

These are absolutely brilliant questions. Personally I try to keep the voltage as high as possible for long distance cable routing. As you want to use a step down buck converter I would implement that close to the LED side of the cables. Next your interested in the resistance for long lines of powering cable. The resistance is directly proportional to the length of the wire. If the length doubles, the resistance doubles. If the length triples, the resistance triples. This website will provide you with some resistance values for different copper lengths/connectors (network Cat6 Cable is a good choice for long distances) - daycounter.com/Calculators/AWG.phtml - Then you just need to work out the load that you're putting on the wire in terms of current and use V=IR to work out the voltage drop and if it is acceptable. As a general rule of thumb 5V will get through 50 feet of cable and still function well for most tasks. I say this as the other concern with long wires is picking up EMI (Electro-Magnetic Interference) when using lengths above 50 feet. Capacitance and RF interference shouldn't be much of an issue at logic frequencies / voltages, but would become an issue when dealing with analog audio, video, or radio signals. Hope that helps!

[@bobcatt2294]

For a situation where you have a battery and you must rely on that one battery for night riding. The power supply is a 12v lithium drill battery which function is to power LED lights. The system must be extremely efficient. The LEDs will be 3.5v so then - 12v to 3.5 - to 5v step-down. LED lights which each can be powered by a 18650 battery. What is best to use? Thumbs up. For this application can you put in series several LEDs to act as resisters? If so, what would that look like?

[@Core-Electronics]

Doing one power conversion is the most efficient way to get power requirements to where they need to be. Multiple Step down/up power conversions are less efficient. LEDs Nodes are best wired up in parallel so that way if one drops out they all won't. And LED are Diodes are not resistors. Whereas a filament light bulb that can be thought of as a resistor. Come check the full written up guide for this video as there is more information there 😊 and if you want further help come write up a forum post here - forum.core-electronics.com.au/

[@bobcatt2294]

@@Core-Electronics Thank you for your response and the resource.

[@BIGDeZeL6]

How Can I piggly back the power from the led on my scooter without breaking the led or overloading power supply? Please help

[@abrahamjerry9626]

Can a 5v output from a power bank be used instead of the 12v shown in this video to drive the same LED?

[@Core-Electronics]

Hey mate in that case your are going to need a DC-DC Adjustable Boost Converter. A great choice would be this one here - core-electronics.com.au/catalog/product/view/sku/DFR0123

[@picalculator84]

of course, but you will need the module to go down to 2.8v from the 5v, and also the courent needs to go down. normal power banks can deliver up to 2A whitch is to much

[@brentkelly5445]

Does a led strip with built in resistors need a driver? I was going to use a boost converter from my power supply (unstable, voltage/current input will vary up to 9V). But the boost converter caps the voltage and current, no?

[@Core-Electronics]

The Converter shown in this video limit both voltage and current. I'm sure the majority of them do but take the time to check the datasheets before using them in your project 😊

[@brentkelly5445]

@@Core-Electronics Can I bother you again. Do you know what "Matched Load resistance" is? I'm trying to power LEDS with a TEG. there is a matched load resistance rating on the TEG. It is nowhere near my LED's resistance. is the load and source suppose to jive ...exactly?

[@Core-Electronics]

Come ask the question on the Forum as well best be able to help you there 😊 there is a fair bit to unpack with your question - forum.core-electronics.com.au/

[@hari_sn5331]

Can i use that step down module for 4.2v to 3.4v ?

[@Core-Electronics]

From the specification sheet which you can find in the bottom of this page - core-electronics.com.au/dc-dc-adjustable-step-down-module-5a-75w.html Input Voltage Range: DC 4-38V Output Voltage Range: DC 1.25-36V Adjustable Looks to me like you definitely could use it to step down 4.2v to 3.4v 😊

[@arnokalayc2054]

Hi, pardon me if I missed a point but I'm not electrician and it is a bit hard to understand :) I'd like to ask a question about LM2596 constant current buck converter (3A max, so it is a bit similar to this one). Let's say, we have 12V 2A power supply. When we step down 12V to 3V, I guess, the output current should increase (in 100% efficiency) to 8A, no? This amount is higher than the limits of the both (3A, 5A). Then when we also step down to current into, let's say, 0.5A or 1A and have 3V 0.5/1A output, where the difference (7.5A or 7A) goes? Is this dangerous? Can harm the converter or burn the house? Should I use a fuse in somewhere in the circuit? I want to prepare a parallel circuit for hobby lightning. Same power supply in one of the circuits will light half meter 12V LEDs strip and the other one, thanks to the buck converter, 3V LEDs. I'll close the 12V strip in day time but 3V LEDs will mostly be open. So I'm trying to understand how can I do... Thanks for your time.

[@Core-Electronics]

Large voltage differences (drops or rises) results in more heat being emitted due to worse efficiencies. The Current drawn by the Converter will only ever be as much as it needs (and no more). There is never any harm done by using a fuse 😊 but we all work very hard to ensure our electronics are top quality. Heres some tips regarding power supplies that should make you feel more comfortable - core-electronics.com.au/guides/prototyping/power-supply-which-to-choose/ The interesting thing about LEDs is that they will suck the maximum amount of current that they can (even if it will break them). The Constant Current LED Driver (the converter) prevents them from sucking too much and breaking.

[@arnokalayc2054]

@@Core-Electronics Thanks for your reply! :)

[@Salman59604]

Series connection is better or parallel for 12 LEDs ?

[@Core-Electronics]

Series is simpler to wire up but parallel will be more resilient to disturbances (a LED Node breaking won't stop the other LED lights from turning on). Hit us up at our forum champ for more 😊 forum.core-electronics.com.au/latest

[@Salman59604]

@@Core-Electronics I am very thankful to you dear ♥️

[@ThePhilbox]

Does the CC current control not just effectively drive the voltage back down?

[@Core-Electronics]

That's right, CC mode will set the voltage to whatever it needs to be to limit the current to the desired setpoint. Usually this means throttling the voltage down until the CC limit is not exceeded.

[@ThePhilbox]

@@Core-Electronics So setting the voltage first is a precaution?

[@patmat.]

So it's not just a current limitator, even when 'short-circuited' by your multimeter in current mode the driver has a constant output... which means there must be an automatic rheostat inside (?)

[@Core-Electronics]

Excellent advanced question. Here is the circuit diagram for that DC-DC Adjustable Step-down Module circuitdigest.com/sites/default/files/circuitdiagram/XL4015-DC-DC-Buck-Converter-Schematic.png. I will also link a datasheet here - magicduino.com/Images/ItemsMedia/File/7193.pdf. Hopefully that will answer your question.

[@Core-Electronics]

That's right! A power supply like this has a "Constant Current Mode" where it will output its set current whenever possible. If it's output is shorted, it will output the constant current it was set up to deliver. We've come a long way from rheostats, but it's a helpful analogy. These power supplies use OpAmps to create the feedback action.

[@Kopsu87]

Step down module with current regulation seems to be quite rare in EU. All I can find are modules with voltage regulation only. Nice video though.

[@Salman59604]

Can I connect 10 LEDs (3watt) in parallel connection with this driver

[@Core-Electronics]

This DC-DC Adjustable Step-down Module can output a max of 36 Volts and 5 Amps. 2 to 2.8 Volts is required for each 3W LED Node. If we use the lower value that will means this module can power 18 unique 3W Nodes if you have them in series. If you want all nodes to be operating parallel to each other you will need to bump up the current and keep the voltage the same (2 to 2.8 Volts). Each node requires 750mA and we have 5A available. Therefore we can only power 6 LED Nodes (5 / .75 = 6.666667) if they are all in parallel loops with each other. If you want more help/more explanation come check out our forum here - forum.core-electronics.com.au/latest

[@Salman59604]

@@Core-Electronics Very helpful for me ♥️ .

[@edgotbait]

Thanks for the info but I have a ? My buddy candles a thousand quail eggs he does them one at a time We would like to build a board with 124 of those cob leds how would I drive them ? #core electronics and help would be great

[@Core-Electronics]

Hey that sounds like a great project. Your best bet would be to pop your question on our forums, we have a community there that can give you some guidance. Just post a question and give us some more info about the project. Cheers! Link to forums: forum.core-electronics.com.au/

[@chandanmishra8211]

How to Connect a 6 pin 3 watt single led?

[@Core-Electronics]

I reckon you must be talking about these Triple Output High Power RGB LED - core-electronics.com.au/triple-output-high-power-rgb-led-49343.html These are awesome because they can produce RGB colours 😊 Depending on how much voltage you give each pad you can get all the colours. Check here for the voltage ranges and Pinouts. - core-electronics.com.au/attachments/localcontent/M018001MA3LZ_552043ff372.pdf This fellow has crushed a great tutorial on them to get you up to speed - kzbin.info/www/bejne/jau8lX5upq-Dors

[@chandanmishra8211]

@@Core-Electronics yes sir,these leds .sir I have few questions: 1. Can I use a ready made driver of 3-15 v ,3 watt driver with it? 2. Can I control the RGB colour by common anode/cathode and using a Chinese controler?

[@oz93666]

Good video , but why bother setting the voltage ? Leave it at 12, setting the current at 750mA will keep the the current correct for one or four (series) leds.

[@Core-Electronics]

Excellent question. Too much voltage kills LEDs. As mentioned in the video, LEDs are current-driven and not a voltage-driven device. If the voltage deviates more than 10% the LED bulb is fused off breaking the node.

[@miteshdhanani]

Insteadof Ac connection if we want to connect it with a 3W 6v 3A solar panel then

[@Core-Electronics]

Heyya mate, so everything in this set up is DC (no AC current to be found, except for coming into the power-supply at the wall). So long as your 3W 6V 3A solar panel is outputting DC current you should be able to use a boost or buck converter (depending on your Voltage requirements, which depends on how many LED Nodes you have hooked up) to get the correct electrical energy to the LED Nodes.

[@miteshdhanani]

Can u please send a diagram, explain

[@muppetpaster]

Or get yourself a CC LED driverboard for about 50ct. Been using a multitude of those, from 1 W up to 15 W, costing from 50cts up to 1 buck and a half.

[@Salman59604]

How many LEDs can be used with this driver?

[@Core-Electronics]

This DC-DC Adjustable Step-down Module can output a max of 36 Volts and 5 Amps. 2 to 2.8 Volts is required for each 3W LED Node. If we use the lower value that will means this module can power 18 unique 3W Nodes if you have them in series.

[@Salman59604]

@@Core-Electronics I am thinking of using DC -DC module ( 9 amp) for 10 LEDs (3W) in parallel with the same setup you created in the video . I mean can I use that 12V 2A charger that looks like a laptop charger for this purpose?

[@Salman59604]

@@Core-Electronics I have one more question. Will the LEDs be safe to use and last long with 9A DC DC module?

[@Salman59604]

@@Core-Electronics12V 5 amp Or 12V 10 amp charger would be better for 10 LEDs in parallel with 10amp DC DC module?

[@Core-Electronics]

These are perfect questions for the forum here, come write up your question there 😊 - forum.core-electronics.com.au/latest - That way other people will be able to find it and glean useful information from it too without it getting lost in KZbin comments.

[@elishamutende]

👆

[@eat-myshorts]

HOW TO CONTROL A 3-WATT LED with PWM using an Arduino??

[@bajwasb867]

Am auto electrician . 1..Q any cars front head light 2 connection 1starting the car . 2 parking . same led 1w & 5w how work up dowon . Can explain . Plz

[@thebraziliangardener8481]

makes no sense whatsoever 2.8x0.750 = 2.1 watts,you calibrated it wrongly