12V 50A 600W power supply - schematic & how does it work

[@bebek1993]

As a hearing disabled person, any captions (either automatic or man-made) would be really helpful for me. I really wish I had a way to understand your videos because I find them so informative because of the in-depth explanations. Only found a few videos of yours with captions. :(

[@gabracal]

Don't worry. There are still people who are willing to write captions for videos.

[@masar-at]

@@gabracal the channel owner have to enable it first I think.

[@TeacherBrunoOneil]

I wish I had his disabled knowledge in electronics.. I'm awful at reserve engineering. lol

[@JCHaywire]

I'm a native speaker with hearing. I've taught English overseas for a decade and I'm fairly good with accents--but I can't tell what pidgin DGW is speaking. He has a very interesting tonal artefact also--my guess is that the subtitles algorithms cannot track his spoken output or identify it as English. Great channel, though.

[@chelarestelar]

I never understand these videos, and same with Big Clive, but I still watch them

[@joerod7526]

You need to know and like electronics....it takes a couple of years .... I' m a huge fan of Big Clive👍

[@BIGRIP87]

keep trying.. you will learn 1 day

[@HazeAnderson]

Do you just listen because you like the sound of their voices? 👽

[@SAHILKHAN-lu8oq]

Keep listening to them. I knew a little bit of Electronics but didn't knew English language. But I kept watching their videos from about 3 years back. Now I learnt Electronics well from them, as well as English language too. 😁

[@alphadog6970]

Same

[@mrfrog8502]

15:10 Because track is really long it will act like antenna picking up switching interference. This 1nF capacitor acts like an integrator smoothing voltage waveform for the comparator inside of the chip. I love watching your in deph videos. Best regards.

[@petehiggins33]

Despite the fact that it carries a CE mark this PSU is not compliant with European EMC standards which require any power supply greater than 75W to conform to limits on the harmonic currents drawn from the mains which effectively means they must have power factor correction circuits.

[@rvqx]

In China CE means: Chinese Export. Clever isn`t it?

[@dwaynezilla]

@@rvqx so basically meant to be taken as CE marking unless it's under question and they can fall back on "noooo it's this other totally legit thing! How embarrassing for you that you would even think it was the same!"

[@CoolKoon]

"they must have power factor correction circuits" - The thing is that all this crap sold via eBay, AliExpress and whatnot is pretty much considered grey import, which means that even though their import isn't illegal or restricted they likely don't conform to ANY local electrical and other standards, not even the right plug is supplied at times.

[@TeacherBrunoOneil]

@@rvqx lololol

[@francoissittler9923]

Hi, very nice video and explanation indeed ! For those who might have encountered issues with this supply, mine broke after 1 month. After investigations, it turns out that the 220nF/100V capacitor (used to connect the Gate driver transformer) was dead (had > 100 ohms ESR). Just replaced the cap and it works again as a charm!

[@rex-up9ln]

Damn! was waiting for another big smps teardown for a long time. Even more watts please?

[@bottering_one]

@@0verv0ltage 1 gw facebook ps when?

[@petehiggins33]

I think that the purpose of the 22ohm and 680k resistors at 11:47 is to adjust the current limit for the two different input voltage configurations (110V/230V). They sense the input voltage via the auxiliary winding during the ON time and add a proportional voltage to the current sense voltage hence reducing the current limit level at the higher input voltage.

[@DiodeGoneWild]

For 115V, it uses a voltage doubler, so the primary high DC voltage is the same.

[@petehiggins33]

@@DiodeGoneWild Oops!, you're right. In that case perhaps it's just to adjust the current limit within the two ranges.

[@prathikprashanth2932]

@@petehiggins33 @DiodeGoneWild its probably there to add a small DC offset to the ramp?

[@prathikprashanth2932]

Oh my gosh I can't wait to see the teardown of the 1000W PSU!!

[@FindLiberty]

EXCELLENT - THOROUGH AND CLEAR - great job.

[@godfreypoon5148]

The 10k resistors on the gates might be to damp oscillation of the pulse transformer secondary leakage inductance with the gate capacitance (more damping in addition to the 10 ohm series)

[@sergepetrov8598]

Also if gate winding breaks and goes open circuit.

[@quicksilva184]

I love your videos with schematics. I try to do them myself but it's not easy at all.

[@Zebra_Paw]

Finally… As always on this channel I leave a like before even watching because I know it will be good. I was waiting for this video since the first video about that power supply. Actually this is the 30 amps model, so its no surprise that it overheated at 50A. I really think you should try the real 50A model, or even 60A. There is something not right in what you said… a forward SMPS doesn’t necessarily accumulate the energy in the output inductor as just like a halfbridge (or even fullbridge sometimes) it doesn’t need to have an output inductor. You can make a feedback-less design.

[@agoveli9537]

Hi, are you going to do any more videos on the metal detector? My friend and I built it but we had some issues namely that it is extremely sensitive to movement and the buzzer remains constantly on.

[@agoveli9537]

We actually found our problem, we had a few electrolytic capacitors installed backwards lol, now or works beautifully, Thanks!!

[@wuukaa9079]

Wow what a work! Thanks for the explanation it was really clear :D

[@dominikgula1840]

Ďakujem za dlho očakávané vysvetlenie 😊 👍👍👍

[@Debraj1978]

Sicne this is asymmetric bridge, is the max duty cycle limited to < 50% to enable reset of transformer?

[@regulareverydaynormalguy6479]

I just graduated electrical engineering, and to be honest this thing looks bloody complicated 😨

[@tunderbird123]

Its not very complicated, it,s a pwm, a power factor correction anda a feedack from the secundary...

[@regulareverydaynormalguy6479]

@@tunderbird123 Over all you're right, Inductor for passive PFC, a controller for PWM and optocoupler for feed back. BUT it's much more complicated than just that, when you're looking on every component usage there are a lot of theoretical thinking behind it, and there are many components there. It's like saying a wash machine is just a motor with a controller... It's much more than just that. Edit: Seems that there are even no Power Factor Correcting, only interference inductor.

[@jmenonenidulezite561]

@@regulareverydaynormalguy6479 I agree, no one mentioned things like parasitic inductance and capacitance of traces on PCB, how complicated is design a propper subber network, calculating dimensions of heatsink, moral age of used components etc.. I know its HW development but you have to count this up when you are analyzing schematic

[@PreetPal2107]

the video uploader is extremely experienced person in electronics he is serious with electronics 😁

[@alialpha8982]

But not impossible to get it up 😊😊😊😊

[@worroSfOretsevraH]

What is the need/purpose of a gate driving transformer, when both transistors switch simultaneously?

[@mike83pl1]

Thank you very much for this video! I have been waiting for it impatiently :-)

[@idrisbabatunde6629]

Great Job my man...very helpful. Thanks for explaining the schematic.

[@rilosvideos877]

Excellent knowledge of SMPS - as always! :-) Could you make a video on typical SMPS topologies and explain their specifics, advantages and downsides? You always mention "half bridge topology", "full bridge", "flyback", "2switch forward", etc. but i guess many people dont understand the differences and specifics.

[@weerobot]

Your PSU Videos are Legend..!!!

[@tw11tube]

Let me join the guessing game: The 680k resistor from the auxilliary winding to the sense pin is for fault safety: Imagine the current feedback path to be broken (e.g. the 680 ohm resistor going open circuit). In that case, the current sense pin would stay low, and the transformer will be driven into saturation. Due to the 680k resistor, the 20V supply (10V/turns at 2 turns on the aux winding) charges the 1nF capacitor, providing a pulse width limit even without working current feedback. The two capacitors at different places of the board are to suppress coupled HF or prevent HF emission at different places. I guess one of the capacitors is next to the chip, and the other one next to the optocoupler. The long trace between (you mentioned it) picks up HF noise, which would upset the chip if it weren't shorted by the cap next to the chip. On the other hand, you also want to limit the area covered by current spikes emitted from sudden turn-on of the opto-coupler, so you short out HF next to optocoupler with the other capacitor.

[@brunobeckers4702]

Very clearly explaned! Congrats!

[@conesillyvalley7182]

While illuminating for the most beginners, he omits talking about stability (pole-zero placement) and effects of flyback mutual inductance as well as effect of the opto-coupler introducing a pole in the feedback loop

[@wegi9621]

Very good saga of this SMPS

[@dr.nadhimrasool2959]

Very hard job to draw these diagrams... Thanks U sir.

[@FreeCircuitLab]

Sir you have very detailed knowledge about power supplies, Please make a 12v to 300 volt DC converter using an SMPS transformer in reverse. It would be very helpful for people because 50HZ inverters are very inefficient as they use iron core transformers and now a days most of the essential loads have SMPS inside so they runs fine with DC input

[@gicelectronics]

THANKS A BILLION, ALTHOUGH THE DELAY ALSO GAVE ME OPPORTUNITY TO RESEARCH AND STUDY ON DUAL SWITCHED FORWARD CONVERTER. AGAIN THANKS

[@alexloktionoff6833]

The resistor on pin 3 is overvoltage/overload protection, if return energy spike is big it will charge capacitor on pin 3 and the chip will start to skip cycles. It also can protect the PSU when feed-back is lost.

[@maxgood42]

11:28 could a POT be placed here to have adjustable current limiting ?

[@jj74qformerlyjailbreak3]

I have this exact PS. So this is going to be awesome.

[@txn775]

I learn so much with your vídeos, thanks. 😎

[@anoimo9013]

good explanation with practical details

[@nyashakapfumvuti8176]

What learning resources (besides your awesome videos) would you recommend? My EE degree feels more like a starting point and I'd love to have more circuit/analysis design books that actually show how to build/ analyze real-world products.

[@ashwinshetty1961]

Switching power supplies A to Z by Sanjaya Maniktala is perhaps one the best books for beginners on power electronics Fundamentals of power electronics by Robert Erickson is also a really good book more inclined towards the circuit solving.

[@bobcollyer181]

DGW-Another great video! I was thinking about the gate pull down resistors and the possible reason for their inclusion, Maybe pull down the gate in case the driver transformer goes open secondary, to make sure the mosfets turn off instead of on. Looking forward to next Vid.

[@TeacherBrunoOneil]

can you tell me the value of the first inductor in the emi circuit before the bridge rectifier ? Mine has melted , lol ... You know I have made this power supply adjustable from 6.38v through 20V stable.. :-)

[@1pcfred]

Even though it blew up I still like this PSU.

[@DiodeGoneWild]

The design is fine, but it's built too cheaply. Maybe it was meant for a bit lower power, like 350 - 500W, and they relabeled it. And it wasn't originally meant to have aluminium windings. But I like the simplicity. It's good for demonstration.

[@1pcfred]

@@DiodeGoneWild yeah well that's the way of the world these days. China ratings divide by 2 and be happy. If you really want 600W output then get the 1200W model. This one's a good 300 Watter.

[@filipeterra8981]

I`ve waited so long for this

[@electronic7979]

Very helpful video

[@hasitharanganath]

thank you very much ..... waiting for this

[@bgdwiepp]

I think the extra resistors from the aux winding to the CS pin is to terminate a switching cycle early if there is no load or very light load on the output.

[@bgdwiepp]

It may also be more slope compensation for valley current mode

[@luboxing]

Really good video! It would be nice to explain if it is possible to slightly the output voltage and adjust the over current protection. I have a 19.5v 180v laptop adaptor and tried to use it for Ryobi power tools that takes 5x3.6v lithium ion batteries but OCP would kick in all the time.

[@sergepetrov8598]

180w/19.5v is below 10A. Not enough for power tools, batteries will give you at least 25A.

[@rvqx]

Great job to find out the scheme.

[@kdcreativity6201]

super amazingggg🤩

[@Axpsonix]

Great circuit description 😉

[@vitorschulter3208]

Thanks for your excellent video. One doubt, why choose a forward topology even having practically the same hardware as a half-bridge topology? Is there any advantage in this topology compared to half-bridge?

[@cemsagdc8977]

I think there is a problem about the drawing for the first segment. When you switch it 230 to 115 , you are bypassing the bridge rectifier with this schematics? I really didn't understand it

[@objection_your_honor]

What are the different types of smps? Did you make a video about it where you explain the different types?

[@klave8511]

Great explanation, this video and the previous one where you rewound the transformer. Will you comment on why it is preferable to use the 2 diodes, marked MVR4100, rather than the MOSFET body diodes for the reset current that you marked in blue? Seems the polarity is correct?

[@bengoodchild883]

Thanks for the great video as always! Quick question: When the primary switching transistors are off you say (around 6:00) the primary transformer voltage is still clamped by the smoothing capacitors to ~320V, which puts the secondary at 50V still. (But not providing power since transistors are off) The secondary energy storing inductor now provides power to the output through the 2nd pair of diodes... but you say the inductor now has a 12V drop rather than the 38V it had before? I ask because if there is still 50V on the transformer secondary, where is the extra voltage drop around that loop to get back the 38V...? Is there a larger drop on the secondary set of diodes or maybe on the 68Ohm resistor on the secondary side? I'm new to more complex power supplies so maybe Im missing something. Thank you again :)

[@nophead]

Inductors store current, not voltage. So the voltage is clamped to the 12V output capacitor by the lower diodes on the off cycle and the current stays roughly the same as it was during the on cycle, i.e. the load current.

[@bengoodchild883]

@@nophead Yeah the output cap clamps the output voltage to 12V which is good, and the energy on the off cycle is provided by the inductor's reverse current through the bottom diodes as it discharges. The voltage on the inductor would be ~12V + diode drop. I was asking about what he mentions at the 6:00 min mark though. That the input smoothing caps clamp the primary transformer winding to 320V which still puts 50V on the secondary (at no load though). If you do KVL around the loop he highlights in light blue you still need to see that 50V drop between the node below the diodes and the node to the left of the two 68 Ohm resistors no?

[@nophead]

@@bengoodchild883 I think the primary voltage is reversed so the top diodes are off and the secondary has gone negative and is open circuit.

[@mehrdadrahaaei3068]

Hi, How the circuit starts when input voltage is 110V? (200 volt zener don't allow start current to enter the IC)

[@WagTsX]

that's an interesting question

[@110v4]

For 100-127V it uses voltage doubler, so the primary high DC voltage is same

[@williamrojas4794]

Excelente explicación amigo, gracias saludos desde Venezuela

[@hengkyambar8161]

hello sir, i want to ask, can the ic contained in the schematic in the video be replaced using the uc3842 ic? it looks like in the video there are two transformers, one large transformer, and another small one, is the small one a GDT transformer? how many primary and secondary turns?🙏🙏

[@tw11tube]

16:02 Your cat on the blanket is the right being to complain about being lazy. :)

[@JCHaywire]

I struggle to understand the language in this video, because I'm impressed with the depth to which DGW has gone with this circuit. The designators have changed, however, now in Sept 2024. I'm trying to find the sense resistor that I need to pull to open up the top voltage with my power supply.

[@esunayg]

best teacher ever!

[@ceilingfanmusic6597]

So if i baught that power supply would it last if i used it at 50% of its rated output?

[@jefftheanimal]

Valeu!

[@DiodeGoneWild]

Thank you for your support ;)

[@jesmartelectronica2503]

Quite good video, I have a supply like that for my 3D printer and i always know it was like not the best quality but seen the details is awesone, have you tought about making a series or tutorial how to design i proper SMPS? there is not much such material in internet, thanks you from Mexico.

[@gazaziho]

Really it's so complicated, Good work to transfer PCB to paper .. I'M REALLY APPRECIATE THAT 👍👍👍

[@fullbridgeelectric]

What is difference between two-switch-forward and symmetrical isolated converters(usually controlled by a chip like SG3525A)?

[@erwinperciva5708]

can you make video about cheap 4-wires switching power supply module, how it works and is it safe

[@alfiolocatelli5093]

I think is the best English accent I've ever heard. I love it ahahahah

[@Zebra_Paw]

13:32 this is more likely the opposite, powering the transistors with a RC filter to smooth out the auxiliary winding high frequency ripple to avoid causing problems to the gate driving.

[@SunilYadav-iv9nh]

Thanks for sharing another great video it helps a lot , i have one question iif any body can help, how can we control or reduce the output current for eg if max current output is 10 amp how can we limit it to 8 amp , so that the supply doesn't go into oc protection mode ,thanks in advance

[@idrisbabatunde6629]

That's what I always tell most power electronic scholars "You have to tear down the board to understand how it works, otherwise you won't be able to build one yourself". The transformer turn ratio (32:5) on this particular SMPS is a great misery. It did not follow the rule book I learnt in school.

[@PatrikFormanek1]

Very nice video :-)

[@ice-0568]

Yes!

[@raymundhofmann7661]

Isn't this basically a step down topology but with a transformer going into a step down inductor?

[@hardscorerockkssss]

what is that hissing sound?sounds like really loud computer fans or cold air fan

[@Dc_tech386]

Hello sir I copy this circuit and the speed of the gate or not discharge fast enough to get the balance current I use a pnp and in1484 diode for discharge but the current drop the pin signals from 15volt to 8volt and rhe mosfet fail upon turn on because the gate current is too weak to fast charge the gate so the gate blows out from the high current for main and the only way the mosfet stop blow out is removed the speed driver that bleeding the 300 milliamp to 100 milliamp bit I lost the speed and the main current keeps going higher I draw 350 watt 14 volt and 9 amp 114vac almost 1kw and only drawing 350 watt because the mosfet switching slow

[@vivekdevvanshi8085]

Secondary side have also a Buck converter like 50volt to 12volt

[@techguy666]

Very nice effort and excellent presentation. It's a shame that they used aluminium winding wire for the transformer and inductors.

[@1pcfred]

The way metal prices have been going you're lucky if you get aluminum today. They've started plating steel wire.

[@DuroLabs85]

0:11 thats how engineers desk lools like if it is clean it means they are not working. :P

[@zaheerahmad5632]

Nice video sir

[@uwepolifka4583]

Maybe I´m wrong but I think the is something wrong with the secondary circuit. When plus is there where the big blue plus symbol is, where does the current go? Through the diodes, through the 2200µF cap back to what? From plus back to plus? There is no minus.

[@johanbooysen3508]

Thank You! Very well explained!

[@nishanshrestha2445]

Awesome🤘🙂

[@clam4597]

Can you still buy those computer paper?

[@xDR1TeK]

How do people design these power supplies? It's quite impressive.

[@keithking1985]

DON'T LISTEN TO YOUR CAT DANNY, THAT WAS A CLASS SCHEMATIC EXPLANATION!. ANYWAY ISN'T CAT'S KNOWN FOR BEEN LAZY!!!! ; )

[@AmatorElektronik]

IC is similar to UC384x. No no this resistor change the threshold current sens pin.

[@vivekdevvanshi8085]

Please make a self oscillating 12v 60w power supply

[@alialpha8982]

Thx sir for your ex...it's soo perfect 😊

[@blainelanders2361]

Can't the PS manufacturer provide the schematic?

[@gicelectronics]

FINALLY!!!

[@dedifachrozi2960]

The chip code/number please?

[@Elekron5556]

2 switch Forward je hodně stará topologie zdroje. Kdysi Mez Brumov vyráběl svářecí invertory s bipoláry, cca 30 zpět.

[@DiodeGoneWild]

Já sem viděl československej zdroj 5V 50A kterej byl "4 switch forward" :). Něco jako tohle, ale použili tranzistory jen na 250V, tak byl každej tranzistor tvořenej dvěma v sérii.

[@Elekron5556]

@@DiodeGoneWild Jedna z šílených konstrukcí té doby. :)

[@baranidharandharan3232]

how to design two switch forward converter gate driver transformer design

[@elyas7911]

Make a video of the Drawing this schematic, please 🙏

[@Крот-у4е]

где субтитры ?

[@Hlas-knih]

1:29 full bridge rectifier :D

[@ЭллаПолянская-р6в]

Просто шикарно.

[@zaheerahmad5632]

Sir piz geve me digrame this supply

[@AURELIOMOREIRAam1960]

muito bom

[@anwarpspsanwar]

Better super I like this

[@ucupbintangtoedjoe4489]

Pdf sir

[@martinbobak3009]

I like llamas

[@acoustic61]

It's no wonder this stuff fails. So compilcated. I'd rather use a linear power supply.

[@chelarestelar]

.