Very odd USB charger SMPS circuit
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- Опубликовано: 4 окт 2024
- Today, let's take a look at a very strange schematic of a 5V USB charger switching power supply. It contains a Poweric PI751 chip and it has no optocoupler, no auxiliary winding, high side switching, floating GND pin of the chip and voltage sensing connected to the primary winding! It's apparently a 1A design (the voltage plummets at about 1.1A), but they marked it as 2A.
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its crazy how some of the most ingenious designs can be found in these ultra-low cost, not particularly safe switchers. i guess we know perfectly well how to make very good and safe power supplies, but there is an art in cutting component count and cost to the absolute minimum and still getting a product that works, just about.
I was wondering (being a novice) if the benefits of this design were purely financial or whether there was a safety/performance or other benefit. I guess your comment answers my question!
@@wthornton7346 if it's from China, it was purely financial...every cent shaved off counts ;-)
Love the reverse engineering. I would think that chip won't last long run like that. Pins 3 & 8 will be continuously pounded with reverse voltage spikes trying to find their way out through pin 2.
If I'm not mistaken, it depends on the amount of leakage inductance.
In some instances, a snubber is actually not necessary!!!
We don't know what excatly is in the chip. I bet the chip has been made with this in mind.
Your cat is a fast learner. Now he knows exactly when to make his appearance: at the end of the video, as all the stars, in order to get the applauses
I agree basically with the explanation of how this works and I would add a few extra comments.
The internal power switch is an N-Channel FET. When it turns on, its Source (pin 8) rises from 0V to +340V and the voltage at pin 1 is pushed up to say 355V by the 10uF capacitor. This provides a voltage higher than the input supply voltage allowing the gate to be driven more positive than the Source, hence fully turning the FET on. This is called a bootstrap circuit.
During the flyback period (when the FET is off) the primary voltage appears across the potential divider which provides a positive sense voltage at pin 2 (wrt pin 8) and this is probably sampled by a sample and hold circuit and fed to an error amplifier which compares it to an internal 2.5V reference voltage. The output of the error amplifier will be fed to a comparator that controls the peak primary current. The error voltage must be positive with respect to pin 8 and the current sense voltage is negative so the comparator will be a current summing type.
I could watch dodgy charger tear downs all day.
hi diodegonewild,
this technology is primary sensing.
you can read about it on the data sheet of ALTAIR04-900
this Chinese unicorn fart powered chip manages to do that without the aux. winding and/or choke like the ALTAIR04-900
Check out the AP3968 for example, or the LT8302.
Various such primary-side-feedback chips have been around for a while now, they're not always popular because the output regulation is not as precise, but it's fine in certain applications.
the same principle - the IC sample the primary/aux windings right before it start ringing. at this moment there is very little current in the transformer so the primary voltage is accurately proportional to the secondary voltage.
such an interesting design that it needed a cat scan...
Automotive RUclipsrs: Dodge Charger
DiodeGoneWild: Dodgy Charger 😆
could you please make a tutorial on how to draw schematic diagrams from PCB?
Your cat really helps.
I think the cat was actually checking the camera set up and the lighting.... she thinks she is the director there.. that is a strange set up though.. thanks for the look..
Your cat was late for the shoot, but then made up for it by taking over the video at the end :o)
Very helpful information
Bonjour,
j'aime bien la réflexion derrière : on a une piste, on teste, on valide.
DiodeGoneWild a justement décortiqué la veille de ta vidéo une alim de ce type avec D+ et D- reliés et une résistance supplémentaire pour Ipad.
"pin number tiu?" 😁 Sorry.
Great explanation. Thanks. You're a genius. Love your channel.
Wow, full body checkup of usb charger by Diodegone wild
Of all your videos so far. Why haven’t we seen a single one of them, where your cat is wearing an ESD strap?
Not even one of those fancy wireless ESD straps!!
It’s almost like your cat WANTS your experiments etc. to fail or something!! 😆
Bo Holbo Rasmussen
Wireless ESD straps 😂
For cats 🤣
Please make a video how to build simple smps inverter, you're absolutely expert in it. I like your explanation. Thanks
Please teardown a good ( maybe branded?) usb charge to see the differences
He took apart a real apple charger and a clone to show the difference in this video: m.ruclips.net/video/nMmySM2nar8/видео.html
Very nice art and font on your schematic :)
Another feature of such design is that you don't have RCD clamping network across the primary, that'll make no-load consumption very low. The chip may ramp up the duty cycle during startup, so the voltage on the primary can't rise above certain level. Well, actually, I think that this chip is constant ON time, and not pure PWM, otherwise it'll still have high no-load consumption.
Ah, your cat took a while to come over to check out the schematic this time. (8:33 for the cat fans)
I think its not surprising we see innovation for further optimization especially in those ultra cheap, mass produced devices where every tiny fraction of a cent counts. But we wouldn't know if you haven't had it teared down ;-)
just wanted to say, your videos are entertaining to watch, and you're a very funny dude. im still subscribed coz i love your accent
Good job. Many thanks.
Thank you
reminds me of the "link switch" chip. I have used them and you have to have a resistor on the secondary to keep the voltage somewhat stable.
Good job .we need oscillator circuit diagram for smps (mosfet driver).
I love your calculator!!!
This charger seems to be really easy to convetr into a tiny adjustable power source. I would just use potentiometer instead of the reference resistor.
Nabíječku by asi bylo jednoduché předělat na malý zdroj s nastavitelným napětím. Mělo by stačit nahradit jeden z rezistorů potenciometrem.
The potentiometer should provide good mains isolation then
It would be enough to use a plastic knob.
You are our second Big Clive dot com coming from the Eastern ! ;)
Agreed.
Big Clive is way too harder to understand for non-native-english speakers and his videos is unnecessarily long
@@dpvng.dpvng. feel free to use the auto generated english translation powered by RUclips.
you mean subtitles? they are unreadable. few years ago youtube make them looks like youtube desighners never seen how movie subs must work and look. i'm personally ok with clive's english btw
@@dpvng.dpvng. I totally love how both of them speak.
If anyone else likes to see their videos but struggles to understand their speech, I'd recommend watching more of their videos, because it usually helps.
I refer to LP3668 datasheets your ic pin should be , Pin 1 = VCC , PIN 2= FB , PIN 3= CS , PIN 4 =VCC?? , PIN 5 = C , PIN 6 =C , PIN 8 = GND
The pinout is a bit different, but it's a very similar thing (also a positive side switched flyback chip).
I was your previous video i did notice the primary sense topology i was wonder what is the chip.. I remember i did saw similar chip when i browse taobao . I try to google and find any chip can do flyback without Aux winding. I found DK125 , DK212 ,DK906 ,DK124 ,DK1203 , SM7525 ,LP3668A . Some of them design without Aux winding but feedback with opto coupler. I try to match the pin out with your schematic , i cant find any chip can match with your schematic pin out. but i think the topology should be similar..
It produces very noisy supply current, I can tell you that. I tried using a power supply with this design to drive a USB bluetooth audio receiver, and it caused a whine in the audio output.
This power IC maybe design for control(SW) led driver ?
perfect...videos
I've seen the blue charger on eBay. Quite an interesting building, but heating a lot, and is dodgyyy.
Nice video Sir. Kindly make video on online ups 1/2/3 kva with schematic diagram. Thank u .
I wonder if this Privileg calculator was made in East Germany (GDR)
A pitty you disasembled the transformer so early. So there was no room to change the resistorbalance at the chip or some of the capacitors to find out how the outpout voltage would change - a pitty this time really!
diode gone wild y u r not making diy electronic projects.
Primary side regulation, hmm... I would imagine it outputs about fiveish volts.
8:33 cat lovers start from here
Today lets take a look at this Chineesee......
So.. today lets take a look at my cat of cooourse
Please explain Smart QUICK CHARGER PD or QC 3.0
Does someone here has a Blackview phone? I have one, and it came with a 2 amp charger. At first it was good, the battery was charging full in only 4 hours. But now after two years it stopped working. Basically when I plug it in it always started to "hiss" at me and it became bloody hot when charging. Now it doesn't do that anymore, and when I plug it in, after 10 hours of charging only about 50 percent of the battery is getting charged. I opened it and didn't see anything burned, nothing seems to be burned out. Maybe I could send it to the diodegonewild, he could do an autopsy and see why it doesn't charge anymore like it used to. It occasionally starts hissing like it should, but after 5 minutes it stops and the charging seizes. During those 5 minutes it becomes bloody hot. Does anyone else encountered this problem with their blackview phone charger? I now am using my moms broken lenovo tablet charger, it supplies 3 amps and 5 volts, it charges my phone in 3 hours. Best charger there is.
It could be an electrolytic capacitor dried out. If you decided to donate it to my channel, you can contact me at danyk@centrum.cz
Спасибо за видео и схему устройства.
My brain is screaming
EVEN MORE SALT!!!!!!!
They've really figured out how to build them down to a price these days. You're lucky you're not just getting a capacitive dropper in those crappy chargers. Here, just plug your phone right into the wall you big dummy!
9:12 it seems your cat want to take a look before you.
just cut wire for shunt and research waveforms to crack secret )))
In theory that IC do wonders, PSU is working well, a small number of components on PCB, everybody happy until you buy an expensive product, very hush-hush, that contain that PSU design and suddenly fails, then when you try to find IC to repair it, you realize it is not available for you to purchase.🤬
Those days people always replace the charger, not the components in it. Everything has the same USB port, so it's easy. The problem occurs when you decide to buy a very cheap non compliant one as a replacement...
Please make videos on fake 18650 battery...please
Next video hidrogen generator.(HHO)
When I see your previous video about this strange charger, I made a research on the Google. Now I forgot the details but by looking at some Chinese sites I found out this chip: LNK603-606/613-616. (www.mouser.com/datasheet/2/328/linkswitch-ii_family_datasheet-8160.pdf) I think that chip is a replica or modification of this chip. Maybe, u can look at it a bit deeper.
only accent brings me here and smps is secondary part of internet.
In how many ways can an car alternator fail? Just curious because my one died recently
Usual modes: Diodes fail shorted, diodes failed open, brushes failing contact, open rotor winding, shorted rotor windings, open stator windings, or shorted stator windings but then there are also potential problems with the regulator not providing field voltage. Luckily you can check the diodes on many units and the windings with an ohm meter. I've had far more voltage regulators fail than the actual alternator. Good luck!
I've seen the effects of an alternator with shorted diodes... the car battery almost melted the wiring harness.
Peter S more or less said it all, but it can fail one more way. The regulator can also fail short circuit and connect the full voltage to the rotor coil. Then you have a massive overvoltage in the car. Your headlight bulbs quickly blow (halogen lamps are the most sensitive to overvoltage). The battery overcharges and spits the acid. Risk of damaging a lot of electronics in the car. I've seen in it a 2000 Škoda Felicia. Luckily, replacing the regulator and blown bulbs was enough. Sometimes the problem can be just a loose or corroded connection to the alternator. Not just the positive, but also ground can have a poor connection. And also the battery can be worn, or something drawing an excessive current. Also the alternator belt can break and fly away :).
And they can fail mechanically. Saw one completelyseized up once with the belt screeching as it slid over the pulley.
this is black magic
Chinese black magic, actually. Don't try to understand ;D
Interesting...
Hey
Six volts per terrrrrrn ❤
No just 0.6V per terrrrrrn 😜
Hello, I would be very happy if you enable subtitles in your videos.
this circuit very bad.
I found the data sheet: fuanwei.com/c473.html
Thanks :) It seems to use the same schematic, except that my version has a lot of components omitted. The pinout is similar, but mirrored. But it doesn't mention that it's PI751, it's a different type number. And I don't understand anything in Chinese :).
@@DiodeGoneWild I googled "PI751" and chose results in Chinese only. Then I found some people selling it and mentioning SD3322 in the description. If you put the page through Google Translate it mentions that it does not need feedback optocoupler or additional windings. Also mentions 5V 1Amp max.
First ?
Does it really matter?
(The answer is no, it does not.)
@@BoHolbo Right? I've found plenty of vids. on spewtube, some several years old, with no comments yet. He should snoop around a bit.
@@BoHolbo it DOES
PLEASE SPEAK NORMAL ENGLISH. IF YOU SPEAK ENGLISH PLEASE SPEAK IT REAL. YOU SPEAK THE WORDS TO LONG.
There is nothing wrong with his English. I think perhaps you are complaining about his accent. How would you react to someone complaining about yours?
Judging by your sentence structure it seems your English is pretty weak. You could learn something from DiodeGoneWild.
PLEASE FIND A KEYBOARD THAT DOESN’T HAVE A CAPS LOCK BUTTON!
Also, if you absolutely MUST criticize someone else on their language skills, you probably shouldn’t be using bad language skills while doing so. It’s just bad form! 🤦♂️
A fine example of Muphry's Law (and yes, "Muphry" was intentional).