The next generation COB LED? (Radical new style of bare LED chip.)
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- Опубліковано 8 лют 2019
- I'm not sure how I missed this. It's possibly because it's a secret that has been hiding underneath a phosphor loaded gel out of sight.
Could this be the answer to the bond-wire problems in the early low voltage 20-100W LED modules? It's a new package of bare LED dice/chip that can literally be soldered onto a PCB as if it was a standard surface mount component. Just a very-very small one. It makes me wonder how they pick and place these and check the orientation before placing on the PCB. I guess the bare chip could be dabbed across some tiny contact pads to check if it emits light.
When I tested this COB (Chip On Board) array with very limited current the LEDs all glowed uniformly, even at the point they were all just barely visible. The same can't be said for the older style low voltage module I also show in the video. It had a high number of defective LEDs exhibiting damage in the form of parallel resistance suggesting film damage. Possibly caused by the wire bonding process. When powered the older module would also extinguish whole rows of LEDs when pressure was applied to the busbars at the end of each series string.
Just for fun I tested this LED with a 470nF capacitor in series to act as an external current limiter. The power indicated by the Hopi was 3.4W and the module put out a useful amount of light without getting warm, and would probably last decades with that very low current. Could be a useful way to switch a floodlight made with one of these between normal power and a low level ambient output.
The contact block on the PCB which was clearly not bear-proof looks more like a push-in style for solid core wires. My attempt to treat it like a Wago terminal and "open the spring loaded contacts" just forced the folded contact strip apart and broke the little tab that is just a wedge that is supposed to part the sides just enough to get a wire back out again.
I wonder how reliable this new type of LED panel will be over time. It's a foregone conclusion that the manufacturers will be pushing everything to its limits so thermal stresses may be an issue.
As with all this style of driverless, or more accurately DOB (Driver On Board) LED module there is no smoothing. So the flicker at 100/120Hz is strong. They could design a COB to take an external capacitor or externally rectified and smoothed supply if they increased the number of LEDs in series to accommodate the higher smoothed voltage while still allowing a margin to drop across the active current limiting circuitry.
I'm guessing that the new LED chips may be limited to Gallium Nitride technology at the moment, hence the use of phosphor to make the red and yellow COBs. The green ones seem to be available either with phosphor loaded gel or as bare green chips.
Note that if converting a 110V COB to 220V by swapping the links the current will still be set higher, so the parallel resistor cluster may need to be adjusted. If converting a 220V COB to 110V the current will be lower than a stock 110V COB.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
www.bigclive.com/coffee.htm
This also keeps the channel independent of UA-cam's advertising algorithms allowing it to be a bit more dangerous and naughty. - Наука та технологія
Just put together one of the Chinese round 60 LED clocks. 12 bucks of parts. Nice kit...took my time and it was fun. At 70 years my eye sight is not use to the tiny connections...but I was happy when all but one led lit up and the digital display functioned just fine. Enjoy watching your videos....and it is true a old dog can learn new tricks...thank you Clive! This old Scottish American still has the skills....
Good result. These kits are quite therapeutic to build. Lots of light and reading glasses helps with the tiny stuff. Head torches are good for detailed assembly too.
Same here Brother...I'm at 50 and my eye sight is starting to suffer for the tiny circuitry.
Just build one of these clocks. New one with speech & music. But not SMD. I'm nearly 50 and need glasses for soldering, too :)
yeah...I'm 71 and wear contacts that are good for anything 2 feet or more away...wear 'readers' for close work...but I can see the monitor here OK with no glasses...and the 'readers' ...I've found that the glass ones, with metal (titanium) frames from the real Optometrist are well worth the $$...I've been using the same pair for about 20 years...
@@gregorythomas333 I'm starting to have problems now that I'm in my mid 40's. I had a plastering business for a few decades and retired nearly 10 years ago.. Wet plaster, that's bright white and reflective being hammered with 1000w halogens, gets pretty blinding when stared at for 8 hours a day / 25 years. I first started to notice I couldn't read newspapers any more because the words would disappear into the page.. and that was 20 years ago. I have a small pile of magnifying glasses and magnifying glasses now.
"non compliant manner" is a catchphrase in the making
The entire layout of this unit is so clean, it comes off as being a demonstration unit for show and tell. It's funny to see that MOV sticking out like a sore thumb.
These are really cool units and light well. Thanks for the heavy handed warning ⚠ on the mains connector.
Man great job on the exploded view, kept me from squinting. That's one of the many things I dig about your channel you take the time to enlarge the fine stuff then print it out for us.
What's more interesting is ..
The video was uploaded today but your comment is 3 days old
@@Slovenec5 Available first to patrons, I think!
@@krnlg yup, no need to fetch the tin foil hat to receive the conspiracy theories this time either 😁
@@krnlg ohh that makes sense
I would rather take the conspiracy theory option tho
@@krnlg or maybe an time traveler. who knows
How do you get non-technicals like myself to watch a 20 minute video on the subject of 'next generation COB LED'...maybe....without dumbing down? Well I just did..enjoyed the subject..and I'm a little bit better for it....it's an art I suspect that the likes of the BBC should aspire too..nice one Clive..much appreciated 👜👍
It’s his voice - very addictively calming - plus he’s super smart.
Non-compliant mushing is perfectly channel-compliant.
It's educational... in that you learn not to press so hard.
That magnification is about what I have to work with on some jobs.
Thank you Clive for all your informative videos with none of the mad background "music" we get so much of these days!
I deliberately avoid music because everyone has different musical taste and it often ends up being annoying.
There is something really pleasing a bout the aesthetics of that board, and the thumbnail of this video :3
Washed with soap and water, as one does with LEDs. 😂😂😂
Had a bunch of these for about 6 months on 24/7 (warm white 50w) And they are all still going strong. Have been impressed with them.
I like this new style of production. I hope they are able to last longer than their predecessors. Amazing video as always!
The Hydroponic Posse are very grateful for your help BigClive.
A large bag of stinky buds is on it's way to you. (and some tomatoes)
LOL , BRO , LOL .
LMFAO .
Prefect Comment .
The solder down LEDs seems like a variant of the "flip chip" package common on newer ICs, "chip scale package" BGAs and so on. Packages have moved away from bond wires, mostly driven by desire for very small packages. If you ever popped open an old can transistor, it's remarkable how little transistor there is in that huge package. Improved device packages and PCB density has been a big driver for the tiny mobile devices we have today.
They are flip chip LEDs.
thanks Clive, your videos are both entertaining and educational, with 93000 views already and uploaded a day ago, you are one of the few that actually provide useful information
I cannot understand how I am so mesmerised by your videos when I have no idea what you're talking about when it comes to resistors, capacitors, pairs, parallels, that blue thing, etc. It's like my ears become dyslexic but I can't stop watching. I love your videos, keep them coming! Poo
what a time to be alive! imagine how cheap these could be in 2 years!
Reminder.. 1 year later. I have no idea what price they are going for... probably obsolete.
Hello Clive
The connector is a push in type, you don’t need to press the button to insert a cable. The button is only used to release the cable. It look like the WAGO 206x series (cheap Chinese copy).
I have worked with these connectors before from other manufacturers. They are designed for the wire to be pushed in freely(as stated above), but for removing they are ONLY supposed to be depressed with a ball-point pen to release.
Thank you very much for the detailed review and explanation of COB LEDs. I did not know the exist and I'm very excited to play with them now.
Your videos are amazingly informative. You're very well spoken, posh some might say, but you have a natural comedic talent. Thanks for enhancing my hobby with LEDs and microelectronics!
Nice review
Thanks for sharing👍😀
I think those connectors are meant to be just poked in, you push to remove.
I discovered that afterwards. Very typical of lighting industry connectors designed for high speed assembly.
bigclivedotcom I opened one on a mailbag video and promptly destroyed it as well.
My thoughts exactly, who needs instructions lol...
I’m kinda glad you broke yours too. I don’t feel so bad for breaking mine.
I should scroll down a bit before leaving the same comment shouldn't I.
Great job. I would love to see you do a series of video of factory tours in China talking about these type of innovations. You explain complex subjects with such ease.
Im blown away by the quality of your videos!!! rock on !!!
Everything described and demonstrated so simply that I very nearly understood what the bloody hell was going on.
I can confirm to anyone who wants to try these LEDs that I have made fixtures in my greenhouse and they are more reliable and generally have longer lifespans than the gold bond wire alternative. obviously grounded with GFI. my lights have CPU heatsink w/ CPU fan and operate below 40 deg C at 50W. each with a cumulative 680HR of runtime to date. It is my belief that gold bonded LEDs fail due to thermal cycling and tend to fail even when underdriven despite the individual chips being rather well electrically balanced.
Do you happen to have a link to the ones you bought? Thanks.
Could you change your lighting schedule to allow for a more gradual warm up and cool down to reduce the effects of the thermal cycling on the old style chips?
It does look like a step toward better reliability, but I've never had anything but bad luck with the driverless designs. Switching or high-freq transients tend to just dump straight through the current limiting circuit. In my experience, that's what ends up blowing up individual dice and taking out the rows. Maybe the unidentified driver chip is something new that addresses that weakness.
I looked in your channel you don't have a vid showing your lights can you make one?
I have no real motivation to invite commentary on my design approach and its associated compromises. Most people are working with more money, or with the assumption of a cooler and cleaner environment. Who actually cares about things being insect-proof or operating with Ta above 55C? Who actually cares about avoiding the liability of active cooling? Who would bother to develop the tools, fixtures, and processes to manufacture their own heat sinks?
Despite the coincidence that I also make my own lamps, you should reply to the person you actually intended to ask instead of the last person in the comment chain.
Anyway Clive, Your microscopic photographing ability is incredible......❤❤❤❤
I love the fact you called out the metal on a lap with power. Stay Grounded... I watched a guy do a panel with 10-20 led cobs. He would fire up the panel after every cob with the metal touching him. His first build was massive. I was waiting for the shock to happen.
Ah, the infamous hydroponics posse...
This is exactly what happened to me when I encountered this type of cable terminal ... you actually have to only press them very gently :)
Same thing here, broke the plastic first thing, right after thinking "neat surface mount terminal". I think it's the temperature resistant plastic so you can reflow solder, brittle crap. Was a quality brand terminal too, not a knockoff.
I hate terminals like this. Give me a good old screw to tighten/loosen and clamp on to the cable.
I mean yeah sure you're not supposed to have tension/support on a cable like that but stuff like this just feels so uselessly flimsy like you'd knock the connections out if you accidentally sneezed on the chip.
Clive doesn't do pressing gently obviously, as demonstrated by his frequent use of the hammer of investigation
I have worked with these connectors before from other manufacturers. They are designed for the wire to be pushed in freely, but for removing they are ONLY supposed to be depressed with a ball-point pen to release.
Thanks for your excellent analysis and good safety tip (earthing the aluminum substrate). Well done!
Cheers from New Zealand. Great information. Keep it coming. Thank you.
The design of the board is genuinely beautiful from a designer point of view
@5:05 If you want to get of lamp reflections, try Teflon tape over the bulbs. It diffuses light very well. That way you won't get as hard of a reflection in the images.
Nice you had your F-up at the start... no fake news here! Love your candidacy!
Thanks a lot. Made an order of 100W 220V LED. Helps a lot because it doesn’t need bulky driver.
So glad I'm not the only one that washes their leds 🤣
We already know the failure mode of these - some guy jamming his screwdriver into the neutral connector. "Trust me, I'm a professional" :)
I just finished converting an old fluorescent desk lamp to LED using two of these. The reflector was a big slab of aluminum, and is serving well as a heat sink. When I shopped for COB LED slabs, I recognized these from the video.
I found myself with one of these somehow, no idea how to power it,
thanks for your vid, very informative and enjoyable,
Ahh! Curse you, Clive! My wallet hates you at least equally as much as I love your channel, man.
Time to grab some of these, as the weather where I live is very humid and goes through extreme temperature changes at times. This KILLS the older-style COB LEDs in about 6-8 months, even with active cooling that keeps them under 70C at full power on hot days (I threw in a couple sensors to one in an attempt to figure out why they were failing) and 55C on most days - my current theory was that it's the gold wires getting weaker as they heat up, and failing just like you mentioned, so that fits. I was so excited when I first saw the high-wattage COBs starting to show up at my suppliers about 10 years ago, but was quickly disappointed. Can't wait to try out this newer style!
But yeah... just when I think "Ok, I'm NOT buying anything else this weekend", you come out with a video like this. :-D
You can always just remove one of the current sense resistors with good results. I always do to reduce heat.
Order a 50w led, if you need 25-30w.
Technically speaking you could just scribe the top of one of the resistors as they seem to be a carbon film on a ceramic base.
@@bigclivedotcom I'll try that next time
Good idea, i ordered 5 of these, the 30W ones, but they run too hot with a fanless heatsink, wich is weird because the DC old-fashioned 30w ones could run without a fan easily...
@@blackblaud Find the lowest value resistor near the chip and make it 30% higher value.
Another great video. Thanks Clive.
Awesome video my friend, Thank you for sharing this!
Clive could you do a update showing temp rise, where the hot spots are etc most of us don't have access to a flr camera. I have bought a selection of these boards, it would be very helpful to see how much heat their is. Helpful video thanks
Regarding lights for lighting and full spectrum cobs that are driverless.
1. On peak cycle is about 25%, rising and falling account for 50% and off 25% of the time in a cycle.
I note this because of rolling shutter that exists when filming with cameras that are 25fps, the effect produces an image that is containing 4 bars that contain image darkening and lightening cycles.
2. They are all driven hard, 220 Volt cobs are sold for 240 volt use, even using that neat trick of yours with the transformer, it is still too much for them if the input isn't lower than the maximum.
I am going to be doing one that is 200 to 210 volt, try to keep it at least 10 volts off 220v.
3. Heat, the two cooling fans that burnt out because these make a fair bit of heat, the cobs I have are 50W and I use a cooling fan on a thick CPU cooling heat sink. Even with cooling to keep the operational temperature below 40 degrees celsius (where the maximum I was told is 60 degrees celsius before failure) if you have a fan that can't cope, the cob can burn out easily.
ON YOU ELECTRICAL COMMENT about people and putting on their lap... That I have to admit made my hair stand on end when you mentioned that and yes, very stupid, these cobs do have some form of leakage to the metal on the back, I noted this when I was testing a cob that was on the floor, positive terminal connected and the LED's glowed enough to be visible, so not all backs are isolated, some are leaky.
ALWAYS (hark at me eh...) ensure you are isolated by not being in a conductive situation as the most surprising of household things can conduct electric in the right circumstances.... Including yourselves...
I do normally wear gloves and wear shoes that are electrically safe as well as all that safety, I have had a few dances with Madam AC.
I have the ECG to prove my most recent break dance routine. Testing one of these MAINS LEVEL DRIVERLESS COB's
These LED cobs are known as "The Widow maker" in some electrical circles.
yes most of them are not properly insulated
a big heatsink and gaming thermal paste always helps :)
That "leakage" is called capacitive coupling. That you see some LEDs glowing with only one wire connected doesn't mean they are not sufficiently isolated.
Thanks for sharing. after watching your video I bought one of those with white LED's .
Dude I love your videos they help me if I can’t sleep cuz they make me sleep not cuz they’re boring my brain just doesn’t allow information to enter when im at home
To get the lint off use electric tape. It doesn't stick to the silicone but pulls off all the lint
Washing with 99% IPA should also work well I think
I see a new market in the industry... I think I'll design and sell specialist LEDs on Ebay, just for BigCliveDotCom to buy... ;)
Just for Big Clive, and his 498,000 subscribers, to buy! (My UV-C bulbs just came this week....)
Just be careful what connectors you select!
New Preamium DESIGN Led COB 240AC/960DC 0.3W with 238 HI QUALITY replacement ceramic capacitors included
I do this for a living as it is.. I should get some to to Clive
Thank you for this advanced review.
nice to see someone else who can fold a piece of paper together with care. I though I was the only ocd one 😂
I'm puzzled how you identified and differentiated this from typical COBs. Will you be posting the marketing information?
I bought it at random to see if it was actually using the bond wires or not. It was hit and miss if my theory was correct.
hope you can take a microscope photo of the LED while it's on! i'd love to see which parts of the chip give off light
Same
Would love to see some more about these awesome little chips, specifically how to set them up and properly wire them to make useful lighting solutions out of them. I just got two and figuring out a way to set them up for my work bench...
@7:50 Great CloseUp, Thank You!
Dude, you need a USB microscope.
It would be really useful if you could try a method of eliminating the flicker (slowly explaining and showing what to do, so that the electronically challenged can have a go) which would make these type of LEDs a viable proposition for many projects. At present I'm using the old style, with separate power supply, for film and slide projector lamp conversions. The 50w are fine, the 100w have mains ripple which makes them unsuitable for movie projector conversions (the ripple interacts with the projector shutter). Any suggestions gratefully received.
What you need are either 2 things:
1. Use a DC-DC buck/boost converter. You will never have a problem flickering with them. Set it to a max current you are okay with.
2. Combined with that DC-DC buck boost converter, you want a very high frequency PWM setup with say a FET and an MCU switching it on 10-100kHz frequencies.
This will allow for the tint to stay the same at the power level you set for the LED, which is important for consistency.
Thanks for this, I'm now looking into buck boost converter. You say: 'either two things', but then ... 'Combined with that' - so - two things? - Also - PMW, FET, MCU - all Greek to me. As I said, 'electronically challenged' - so ... fewer acronyms, specific products, appreciated. Thanks again, Horipet.
@Undefined Lastname Something like this then would work great:
www.aliexpress.com/item/DC-DC-boost-converter-Constant-Current-Mobile-Power-supply-10A-250W-LED-Driver/32790779943.html
I've actually used this one plenty of times, and no flicker was observed.
@@horipet Ah no problem there.
What you want depends on your power supply.
If you want to downvolt from high voltages(like 36-48V power supplies), what you want a is a buck converter:
www.aliexpress.com/item/300W-20A-DC-DC-Buck-Converter-Step-down-Module-Constant-Current-LED-Driver-Power-Step-Down/32817841374.html
If you want to up the voltage from low voltages(like 12-24V from a laptop adapter), what you want is a boost converter:
www.aliexpress.com/item/DC-20A-1200W-Boost-Constant-Current-Module-Variable-Voltage-Power-Supply-IN-8-60V-Top-Quality/32766741205.html
The other stuff is not necessary for someone starting, as it starts to delve into more complex stuff :)
@Undefined Lastname Precisely.
This is why using constant current drivers is stupidly important with LEDs.
For max power, I usually just limit the DC-DC converter to say the max rated current.
As LEDs heat up, their forward voltage goes down. Without a regulated current supply, that means the current drawn would go up, meaning the LED would get into thermal runaway if something bad happens.
So, I linked some constant current converters that have adjustable current potentiometers. No problem there.
Lol! Oh my gosh you are absolutely hilarious! I love watching your videos!
Fascinating. That assembly method could definitely save money in manufacture. Time is money for expensive manufacturing equipment and it takes a relatively long time to weld on all those wires.
When I heard the crunch, I cringed mightily.
Anyone notice the photo was taken before the breakage?
@@geniferteal4178 nope
The reason I bought the blue one is _I need some extra blue in my vegging room_ 👍
Blue LEDs are not covered with a phosphor layer like the other colours.
But we like the "super full on bear strength" :)
And we LIVE for "loud bangs & skid marks"!!
Wow...they have really come a long way with these COB/DOB chips!
And they are finding inventive ways to automate the build process to take out the "human error" issues.
I have a few of these, They always draw half of what they're sold as, but they make great 50w (advertised 100w) chips. I even have some down into the 365nm UV range.
I wonder what would happen if I put 240v (well, 208v, since we're Y tied here in my condo) across these chips. Maybe I'd get the full 100w? I don't know enough about the circuit to really tell.
As is, around 63w from the wall, they put out 4800lm (from 1") in both the warm and cool white phosphors. Since these are directional lumens, I find this to be much more efficient than HID's with reflectors. I grow all sorts of things indoors (orchids, miracle fruit, a planted aquarium, a few different types of home-made chili hybrids etc.) The real issue, is soldering the connections. The push terminals suck. Just reflow the push connector off, and solder on some nice 14g cable. Epoxy it down. The traces rip off easily. And there's no way to fix this. Not a huge deal with a 2$ Warm White LED. Big deal with a 85$ 365nm LED.
I have had a few chips short to their aluminum backing, so I now use 0.5mm mica for anything I can't reasonably ground (For example, I have an array of 8 of these, and I don't want any shenanigans). I also cover the entire drive circuitry with a very thin layer of epoxy (think 90% epoxy, 10% pure isopropanol to thin the mixture, painted with a paintbrush - as there are MANY holes in the epoxy coating that are a bit bitey.)
As for cooling, I can drive these all day with a 100x60x25 mm aluminum heatsink, with 1cm fin spacing and a 60mm fan running at 5v. I can run them all day with a 80x100x20mm 5mm fin spacing, copper sink too, fanless (fins up) but I've lost like 10 6-32 taps to copper blocks, so aluminum it is. Use a good quality thermal paste, the white stuff sucks. Even cheap Chinese knockoff silver paste or Arctic Silver. I've had great luck with an indium (60) / bismuth (25) / Tin (15) alloy (just melt them down, warm your heatsink to 70c, and put around 2 grains of rice in between your mounting holes). I've been able to get die temps down from 110c to 98c using this alloy, and I've lost 0 LED's since. Just, do note this expands when it cools, so springs are NECESSARY for mounting. Like a CPU waterblock. Tightened to 95%, hard mounting will flex the COB, and the the internal bond wires separate, and you get Blinky LEDS, overdriven rows/magic smoke.
The 365nm and 375nm LED's that I have are very cool. You can see 375nm. It bleaches my camera, too. Neither my camera, nor eyes can see 365nm (I wear OD5 glasses obviously) but my lux meter picks it up something FIERCE. Not to mention, everything in my city block fluoresces. I have some Rhodamine 6G for a dye laser I'm building (as soon as I can figure out how to pump 99% methanol) without spending a fortune) and the UV splash, off a white wall, causes it to lase in a cuvette... From around 30 feet.
Oh, and the 390nm 10w LED's produce a great tan and are wonderful for SAD.... Just, wear some OD2-3 glasses in the correct range.
Clive buy a usb led microscope pen thing, well cheap but handy, I think mine was called angel eyes or something.
But then he wouldn't be able to draw/write on it. And if you think about reading the labels of tiny ICs, then the normal magnifier is easier and faster. ;)
Presumably you can print the output from the USB one. I immediately thought of the Intel Play microscope (which I heard about being incorporated into professional equipment). Probably not supported by modern Operating Systems though.
Screen print
@Matt Quinn USB OTG would possibly allow no change to his workflow and higher quality up close shots. Not that I'm complaining, the picture was very nostalgic to me. Something about the bloom and slightly fuzzy nature reminded me of looking in microscopes in the distant past.
@Matt Quinn absolutely agree. Just thinking out loud.
ZOOM AND ENHANCE.
The main thing is to keep them COOL! BIG heat sink needed for long life!!!!! I put 20% / 600 grit diamond dust in my silicon cooling paste and I get 200% more cooling due to faster heat transfer. Diamond dust is the most heat conductive stuff around for the money.
Talk to me bro
Nice video with explanation
I still do not like this kind of leds
Flicker by default. But they are now doing the 10 x 10 retrofit for the older ones that can run on the current regulated drivers. I've just ordered some. Very hard to find in amongst the older version, and hopefully they will actually ship the new version.
@@bigclivedotcom Hi Clive, what if you buy 3 x 110v and put them in series?? I think 36 led x 3v x 3 cob = 324v and 240 Vrms* 1.41 = 338 Vpeak, so you can use a bridge rectifier and cap before the leds. That coud solve the flicker and current limit circuit will never kick in
@@proyectosledar yes
Project idea: Solder a big smd capacitor across bridge rectifier dc output and see if flickering is gone.
I did try a remote capacitor on another COB module. It has to be mounted away from the heat.
that means more volts for led
If the controller operates in a linear mode, you'll drastically shorten its life.
@@bigclivedotcom on your past video "Adding a capacitor to a driverless LED and other tests" you briefly talked about adding a Capacitor in series to make a low power LED at 8:33. Could you explain what you meant please?
@@everardohernandez8036 when you are powering something from an AC power source, you can use a capacitor as a means of limiting the amount of current getting to the circuit. You would put the capacitor in series with the AC power source and it would create a capacitive dropping effect. This is how they make cheap LED mains powered bulbs. Capacitive droppers are nice because they do not release excess energy as heat. When you use a resistor for this purpose you do release excess energy as heat.
This article talks about capacitive dropping and can probably give you your answer.
www.digikey.com/en/maker/projects/965d2328b35e43079e4eb99cf717137f
Good analysis!
Interesting. I bought a similar thing (different form factor) a few months ago to experiment on since it was very cheap, but then I realized that it takes main voltage. It's been sitting in a box since. I might dig it out after this video :)
Clive braking stuff again with his raw power
I'm not sure if they don't teach earthing in China or if these engineers just don't care about safety at all. Well those suicide showers and water boilers that Clive tested do exist, so im asumming it's the latter. It's good practice to open up and inspect any cheap Chinese mains powered device prior to powering it on and getting a loud bang or even a potentially lethal electric shock.
This is not a finished product only a subassembly. When you design a product using these modules it is your job to earth the casing. Most of the full products, if we ignore the really letal ones, are designed with earthing in mind but incorrectly assembled.
If you've never been to china then I can confirm it is the latter....
Thanks so much for this. Reliability and longevity has been a problem with some of the fitments I've done; most customers expect LEDs to last decades. I have ordered a few of these to test. The current mode chip might be a LC5910S from Sanken (or a chinese copy).
Once again, thanks.
Clive great video! Thanks for your work.
I bet you have heard this before but just in case, it's weird watching someone reverse engineer a Chinese product.
FULL BRIDGE RECTUM FRYER!
No ayporos. That would be for a different type of video. Probably not UA-cam.
@ 4:35 try telling my boyfriend that smh
Time to get a new boyfriend =)
They attach them with a tiny drop of superglue and then melt the solder and bond them with hot air or sometimes wave solder depending on the components. They have had this technology for a very long time. I have a hot air bonding machine with a temperature controlled chimney and a tiny vacuum cup for component removal, as well as a handheld hot air soldering iron. It takes good eyes and a steady hand.
Great video man
Two years later, this is how the LEDs are mounted in my Wal-Mart brand lightbulbs. The singularity approaches 😨
I was very impressed with your microscope shot of the LEDs, must have been pretty tricky to get it just right.
It took a lot of time to get a clear enough image.
Very intresting Big Clive
Looking at the new construction without bond wires, I can see advantages in heat dissipation also. I should think the pads would also act as a little heat sink for the LED's.
IT would be good to have LED's that actually last until the LED's actually become too dull to use rather than spontaneous failures due to bond wires failing.
Clive I have worked with these connectors before from other manufacturers. (Sadly Bosch has adopted these for some of their security devices.) They are designed for the wire to be pushed in freely, but for removing they are ONLY supposed to be depressed with a ball-point pen to release.
Interesting video. I haven't played with this particular LED type but I've discovered the G4 & G9 Halogen types can be used to dump potential in charging systems. I've been getting good results. I might look for this type in your video & see if they can also be used.. Great video.. thanks for sharing.
Nice video 👌
I stumbled upon the low voltage DC LEDs 4-5 years ago, and built a pair of 30W work lights with cooling fans, and a AC-DC power supply. They are still working.
A year or so, later, I went back to eBay to buy more, and begin to replace my old floros in my shop, (I priced a box of 4' tubes, and choked on the price. It had been 20 years since I had bought any, I'd been using used bulbs I got from a local grocery store which was replacing all bulbs every six months.)
I discovered the 'next gen' COB LEDs, with the integrated AC-DC power supply. I bought a full watt range, (30W to 150W), in 240v AC and 120v AC versions, from two different eBay vendors. Some of the LEDs were identical from the two vendors, but about half were a different design.
I was excited about going completely LED, and being able to see, again.
It took me weeks to brow beat the vendors into providing me a 'suggested' operating temp. When I got the suggested temp, I was able to test different heat sinks until I could get a stable operating temp.
I installed 5-6 120v AC LEDs in my shop, as tests. Within six months every one of the LEDs has failed. They lasted different lengths of time, some failed over the Summer, but others failed during the Winter, in an unheated shop, which makes me question an operating temp.
One of the eBay vendors promised a three year warranty, but I haven't got around to testing the promise.
Do you have any speculation regarding the failures? Should I experiment more with operating temp, and heat sinks? Or am I looking at an over current issue/ gold wire problem? (one vendor was boastful about 'their' design using gold conductors rather than aluminum, being the newest, superior design).
I desperately need to get some lighting, but am hesitant to buy more, soon to burn out, LEDs.
Any suggestions, recommendations? Me« very much a beginner in electronics.
Thanks, for any suggestions, or thoughts.
The modules are improving over time. The biggest issue is the manufacturers over driving the LEDs.
Was afraid you would say something like that. Well, I bought a bunch of auto and non-auto 12v COBs. Originally planned on using them as equipment mounted lighting; guess I'll focus on those, instead to get some illumination back.
Thanks, anyway. I seem to remember you did a vid or two about the assembled COB worklights. Have you heard anything about their reliability being better than the bare LEDs?
Another quality product...
Thanks BigClive. Having the connector there is a wonderful addition to these "Driver on Board" units. Good to note how delicate they are. It's very interesting how they have streamlined the manufacturing process, it's quite clever.
That array of 12 X 12 LED's...I like it...Phillips has 3 watt (340+ lumens) white 'dies' that are 1 X 1 MM...SMD type stuff...they do have even smaller dies...seems I read a while back something like .4 X .6 mm...and yes, a lot of these boards like you're showing make it clear in Mfr. instructions you need to isolate the board electrically...but still have good thermal transfer....to that heat sink and fan...
And I've examined a few red and green LED's from lighted pushbuttons...they were about the size of a grain of salt, maybe a tad larger for the green......I'm not sure of that actual size, cannot find my Mitutoyo calipers...I recall the first red LED watches...they were very small, the LED's, not the watch...5-6 LED chips for each segment of that 7 segment display...and that was in the late 1970's...!
A little while ago I took apart my old alarm clock/radio, and the display board was pretty interesting, it is pretty much like the first LED COB you showed, but there's none of that gel stuff over the LEDs, just a little bit of conformal coating, and the bond wires don't look like gold, I've just had a look under the microscope and they are silvery wires, maybe just covered in solder, or maybe actual silver, that would certainly be cheaper. Not sure exactly how old it is, but I'd guess late 90s.
I know this is a bit late but I believe that the micro LEDs may be laser soldered as that gives greater accuracy and reduces the chance of thermal damage.
Fascinating Clive. SMD package sizes are easily down to that size now, I wonder if you can estimate the size of those LEDs. Look to be in the order of half- to one-millimetre.
I was using aluminium substrate PCBs back in the 90s. The dielectric between the copper foil and the aluminium is typically ceramic and is proof rated to several hundred volts. But as you rightly point out, any damage to that layer is potentially catastrophic. The edges in particular are especially vulnerable.
I think this technology will be inherently cheaper and more reliable than wire bonded COB technology, so a great development.
They're tiny. I'll try and measure them.
Thanks Clive, an interesting board.
These are certainly in the right direction from the ones you tried a couple of years ago (20/30/50 W). Easier to replace in fixtures if careful and they look more reliable.
I have had the unpleasant realisation the old type was changed. They kept the power rating but decreased the number of led cells for the same power. What looked the same, was in fact a worse and harder driven gen.2. Same price, same vendor but worse product for a slightly higher price.
Very helpful thank you.
Nice finds, nice sheets. Again, as always [17:47] Can't imagine measuring 230V on my lap. Having seen and felt effects of 230 mains on carpets, DMM, hands, feet etc. since I could handle a pliers and screwdriver and 30 years later still have stupid things happening. I guess having a table can be a thing. Or its something with priorities.
That flickering is pretty poor!! Great video!
Excellent