12V 5A LED switching power supply - with schematic
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- เผยแพร่เมื่อ 9 ธ.ค. 2017
- Today I tested a 12V 5A 60W switching power supply that cost me only $3 including shipping from China. The listing says it's for LED strips, CCTV and LCD monitors. The actual current capability is only 3.5A and some parts are underrated. The PCB board definitely seems repurposed. It looks bodged, but I have seen much worse SMPS designs :). This one has a proper fuse, EMI filters, very good isolation distance on the PCB and safe X2, Y1 capacitors. I managed to reverse engineer a full schematic of it. I also explain in detail how does this switching power supply work. One of the viewers helped me to identify the control chip as XN1049 (thanks!).
Autopsy of the switching transformer:
• 12V 5A Switching Trans...
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Sir, I can only say that your wire stripping skills with those pliers are equally amazing & impressive. Extra points for the dodgyness of using the wire cutter of regular pliers for stripping.
i learned more from youtube than my 4 years of Electronics and Communication Engineering,Thank you Sir
Awesome wire stripping skills man
DiodeGoneWild doesn’t need a wire stripper. Extremely fast AND accurate.
Excellent! There is no other TH-cam channel that does the explanation this good. 👍
I beg to differ, take a look at bigclivedotcom
I think DiodeGoneWild still explains better!
@@jaywenden1939 Diode is an electronic engineer, clive is an electrician.
Dany your reverse engineering skills and knowledge are truly outstanding.... thank you so much for sharing your knowledge it is really valuable info for people who want to learn and is so appreciated
Really nice! You have had quite hard work to do schematics and also explain everything. Thanks!
Absolutely fantastic! Absolutely one of the best I've seen on TH-cam. I'm learning so much from you. Thank you very much.
After finishing a 5 year electrical and computer course, i am still freshman watching his videos.
How the hell does that work?😮
very good practically explained and good way of reverse engineering.
Congratulations to you for good presentation on this difficult subject of SMPS.
LOL "flying resistor"--epic. very good circuit analysis
My new favorite electronics channel!
Very glad to see you are not just believing in what the label reads “says “ thanks
Keep up the great work
If they didn't overrate it and advertise that it is repurposed on the eBay page then it might not be so bad. Also props to you for making such a huge schematic. It is probably from a laptop power adapter or something, at least you can tell the original manufacturer made good quality power supply.
Thanks. I learnt about Y capacitors in switch-mode PSUs thanks to this video!
I just have 2 laying around and i used one to power my HV SMPSU . It blew up in flames! Fireworks!
Very nice analysis of the board/reverse engineering of the schematic, and good explanation of the fly back converter topology.
No Words
That schematic man! You're awesome!
WOW. Thanks for spending the time to reverse engineer this. I just discovered your channel. You do great work reversing engineering many other things too. I admire your dedication. I appreciate it. Viewed many old vids and subscribed. I will be watching for new vids. Happy New Year.
Damn you are good with those schematics. That would have taken me over 4 hours to do and lots of frustration.
How long do u think it took him? they guy worked hard on that schematic.
Umm with the power of video editing [jumpcut] think again.
He is fast to draw a schematic
Quality video, I enjoyed the layout of the schematic and how you explained each section, great way to learn.
I laughed at the flying resistor part :))
Resistorgonewild
i did exactly the same lol
Dodgy bodgy
😂😂😂
A very through analysis of the flyback supply. Thanks, a great job! A couple of points needed clarification-
- Why is a snubber put across the secondary schottky? Is it because they are underrated?
- There is a choke drawn connected to the drain of the MOSFET; is it needed, and what is its role?
Your explanation was very complete. I would like to have had you tell us what should and would have been changed to make it the 5A as noted. Thanks for your video.
Wonderful explanation. The chip is most probably a SG6849, a PWM Flyback Power Controller.
Great walkthrough and analysis. I appreciate your humour also
6:14 - Impressive work sir!!
yes it is. Just amazing.
Your reverse engineering is amazing work. How long did that take?
i havent seeing better explanation then that.... and you pulled a schematic out of it, ....it is insane work. good job. loved the flying resistor :) that was funny..
Excellent and thorough review.
I love ur accent. It makes that channel special and the fact that u use russian old tools is even more impressive. Im subing on 3 accounts:)
Big isolation gap on the back of the PCB but the heatsinks bridge the primary and secondary sections on the other side and just have insulation tape for isolation.
Your video was so very well put together,very entertaining, thank you👍
Nice post- very thorough, informative, and well presented.
Thank you for this thorough review
wow! your so good at this man!! keep it up :D
At 4.09' a dodgy bodgy! Lmao😂😂😩😭😂😂. I just love this dudes accent, and his skills are second to none. The right mix of Information and humour. Well liked over here.🙂
2 years later your video is still a source of knowledge. Just need to figure out how my power supply varies and
what controls the voltage. The PSU is putting out 20v for an item with an 18v max input.
Need to figure out what to change to drop that, without resorting to an external dropper, but it needs to handle
5 amps. Far more components that your power supply, shame about the output voltage. Thanks.
Well for $3 you did get a nice box and some good active/passive components for other projects.
douro20 Exactly
Or a 3.5A Power Supply witch is nice fort this Price! :D
Actually I think the manufacturer might just put a recycled circuit board from another disposed proper transformer into a box and randomly soldered the connection. A lot of Chinese fakes are done like this.
Very impressive schematic overviev
I like how you perform the tutorials
You just did manual PWM - BY DEFINITION! You rule, that shows creativity and capability to think outside the box or globe or what ever other shape you're ever faced with =)
you are one awesome engineer bruh..
thank you sir for explaining how a flyback topology works! this explains why a power supply (like a monitor inverter board) will pulse on and off if there is not enough capacitance on the output (because of dry dead capacitors). after the mosfet first turns on the transformer is pretty saturated, when it is off the voltage on the secondary goes through the diode to the output and only has a small current flow (no capacitors to take in the current). at this point the core is still mostly saturated and when the mosfet turns back on the inductance is really low and the chip sees the high current and shuts down.
Nice job. One of the best circuit learning channel. Please cut the wings of that flying resistorr
I love the way you are stripping cables.
Btw. It is very disapointing how they cheat on power of this adaptor. I've got 12v6a to power car radio at home and its twice as big.
"It's a flying capaciterrrrrrr!"
No its flying resistöör
@@null7969 and dodgey bodgey 4:08
@@HighestRank XDD
@@null7969 öõäü? Estonian?
@@cuf_ Finland
Your videos are best thing on the internet
Idk how yt alogarithm work. I watch electronics for quite sometime now. To see how inside of these stuff thing work. And just discovered this amazing video a while ago. Really nice stuff to learn how electronics work.
Thanks for your work! I'm impressed!
really interesting. Thanks for the clear walk through.
Second channel: "The Flying Resistor"
wow excellent schematic explanation
hi sir i saw your video i want to say you are perfect..you are very good teaching...thankyou for make this video
Good explanation. More videos please. I am learning from you.thanks a lot
Thanks, that was a great overview - though I did miss seeing the cat.
Thank you. You are awesome. Please keep up the great work. Learning a lot from you. Take care. :)
Cant wait to See you in the the next videoooo!!!
Cool video! There is also a spark gap between primary and secondary.
U are so good dude u know what you are doing though u have nice funny accent hh best job
I can listen to that accent all day long!
V nice video deeply explained power supply. Thank you sir for a making video! 👍🏻👌
Nice !! Love ur videos ... Love YouGoneWild !!!!
great work. love your channel.
Thanks for your worknand good explanations. Greentings from PL
today i land on this youtube channel and boom all my problems are solved thanks so
Nice schematic and explanation. Here is a useful trick. I use switching supplies like this in my PV solar system that has a 50V dc BUSS. Many of these work down to voltages below that at very reduced current which is fine for an isolated high side FET driver. The 3 resistors to pin 5 can be reduced if the supply flashes or has trouble at lower voltages.
What if the supply does not come on at all
congratulations for your good job. Thanks
Good and helpful for my understanding on the circuit. Very much thankful. Would you give more detailed explanation on the same parallel resistance circuit for power dissipation? Just one resistance seems good for saving space and material cost plus installation work .
Excellent Explanation Sir....Want individual Component checking and making simple step by step projects on the breadboard with circuit diagram e.g. Schottky Diode, Relay, Output Filter Coil, Mosfet, Transistor, Fet, Optocuplor etc. as per your choice. Then many people with basic electronics knowledge can enhance their knowledge on higher level.
thanks so much for your videos I have gained so much
To disassemble similar BP, I use this method - I dial acetone or solvent into the syringe, I spill the seams carefully and on a little and then I try to disassemble the knife. If the first time does not go, I suture again. Usually 2 -3 times enough. Sorry Google translator.
If you dip a cotton bud in turps and run it around the perimeter of the join on the casing, you can pull the case apart easily.
You´ve done a nice job!!
Another great video. Thank you.
Excellent video! Thank you!
Nice explanation !
Very informative. Good video
thank you so much the
6 pins package control is (OB2263)
It seems the PCB was taken from some other machine and placed inside a new box to sell as new. Cheap Chinese PSUs are generally repurposed. I even got used fans, sold as new.
@DiodeGoneWild
You can open cases like this using hammer and kitchen knife. After a few hits it falls apart pretty nicely without damaging the case, so you can glue it back...
Just pulled apart a laptop charger, it has the same case and many components are the same EG. main cap, rectifier, heatsinks, toroids and the transformers (visually similar). It did have a strange fine grid/mesh pcb soldered and glued underneath, I think it was for RFI absorb and cancel. 240AC - 19V 4A . strangely it made a very faint ticking noise when operating. Used to make a nasty crackle when plugging into mains (no inrush damping). Quality seemed reasonable.
I love the way u talk man..
Thank you for this interesting tear down! I just bought 2 of those SMPS 12V / 5A in an aluminium housing - the internal built is very similar but not exactly same. Do you have the schematic somewhere for download or could you take a photo please and provide a link? I would like to mod the output adjustment a little more, as it allows only for around 11 to 13 V. Thank you!
The wayyyyyyy you talk veryyyyyyyyy funnyyyyyyy.
Thanks alottttttttt 👍
Nice video ! That big heatsink crossing the isolation barrier is kind of worrisome, though.
Yeah, that struck me too. I'm assuming in the original design it was grounded, but now it's not, it's just like a busbar in-the-making between high and low side?
All is very good and ultimate, but why you are not showing number of main pwm chip in all power supply.???
For the diode and MOSFET ratings they might be ok as there's a snubber to limit the reverse voltage.
Good channel. My respect.
This guy has the greatest accent on YouTuuuuube.
Great video
Yep they repaired an unknown 12v supply and chucked it in a box, sloppy too.
I like the fact that the supply has almost everything to be a decent supply.
So do you think the bulk v capacitor is supposed to be 47uF?.
And the output wire is really too dam thin.
I wonder who actually made the pcb.
I have one of those cheap generic 19v laptop chargers (no i didnt buy it lol), model up-060s, it has bits missing, but it is based around the ka3842, and that chip seems do a fair job.
The transformer core ferrite is loose lol.
Even 47uF seems small.
I've taken apart genuine HP laptop chargers. Not only were there mostly Japanese caps (Nichicon and Nippon Chemi-Con ... except one different model had some Taicon caps. Not too bad, but not the best.), but the bulk caps have all been 400V 100uF.
Hmm i don't know really, and at 19v 3.16a 60watt its the same as 12v 5a, so you could be bang on there :-D.
i did put a question mark after my original question, i don't know you see lol.
You seem like knowledgeable people. I'd like to know why this dude hasn't been electrocuted - he has the power supply plugged into the mains and live wires exposed. I'm not trolling or anything, I'm after a genuine answer as to why?
its a danger only if you forget the nature of high voltage, he has bucket loads of experence with really high voltages that would make mains voltage look silly.
Experence and rules keep him safe.
Alpa Chino it's a direct current, and it's just 12v, it will only tickle him when it touches his skin, no sensation touching the palms
Hi, can you explain why? When I touch any SMPS (12v) at the + or - output with a 230v ac test pen, the test pen neon lamp lights up. If I were to touch the output +12v I will get a tingling shock. NOTE: all my one dozens of 12v SMPS power supply none of them has an earth/ground connection at output or input. Can kindly help explain: #1. WHERE & HOW ac current manage to seep/superimposed into the DC output? #2. What is the function or purpose of having an AC current in the DC output. Thank you. Will appreciate and look forward to your help. PS: you can test it out by using an AC test pen at the output and see it light up.
Can you please tell me the resistor value (Ohms and watt) which you used for testing ampere of switching power supply.
love your video
Master you are.keep going
Nice work. I miss your ruski osciloskop to show output ripple.
i had one that said 12v 5A but it cuts off at 1.7A ? turned out the power supply was a quarter size of the box
I have many 15v d.c supply panels that is new and isn't working, all the components tested good, except that the MOSFET isn't powered, I narrowed it down to the control chip and the switch transformer, is there anything I can do about it to make them work?
Wonder if changing the output diode would've improved the current rating
I bought an aftermarket laptop power supply and I noticed it interfered with nearby radios. I guess the reason is due to the lack of ground connection and the output connected before the filter inductor.
The output inductor is out but the tow capasitor is in parallel so 2 output caps are in use.