How to drive a Flyback: Mosfets (Part 1)
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- Опубліковано 1 лип 2024
- I try to practically explain the basics of driving a Flyback and the basics of switching things in general.
I killed so many 555 timers and power transistors making this video. RIP.
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Great video - well done. So nice to see the waveforms and actually explain what's going on.
Thank you for the video ,very well explain, when I was young kid, my father do have Silvertone 1954 Flay Back just to be like a inductor coover in wax.
The only way to fix it was covered in diodoran plastic tub however Spark jumping to ground, that was 1967 we’re the only TV in the neighborhood, part was impossible to get, you bring me good memories. Appreciate it.
Great video!! You explain things VERY well. I learned a bunch. Thanks!
Why doesn't this have more views? This is top quality content
Informative video & very well done. Just keep it up. Really appreciate your videos.
I love your explanation
GREAT VIDEO!!! LOVED the humor, in addition to the info, which was fairly understandable to this 67yo noobie to electronics, (I'm not counting what I knew 45~50 years ago; since, that was like another lifetime ago...)
Very well explained I'm also an amateur, lot of good stuff you covered thanks.
In a triangle wave the wave is in the linear range while switching from low to high as well as high to low this is the area which creates the heat, in the square wave you have a very fast rise time and dropout time. You have to look at the times between 90% and 10%. So with a square wave very little time is spent in the linear range creating heat, when the rise time and the fall times become too high mosfets can have pretty violent flare up’s or mini explosive destruction.
He can use a diode to regulate the power in the inductor
Either way, use that bad wave
Very well explained 👍😊🇮🇪
Like the colour scheme on your scope 👍👍
A well deserved subscription
TV line output transformer frequency is normally 15,734Hz for NTSC or 15,625Hz for PAL.
I have learned many things with this video😊 so Many many thanks for Information and Knowledge ❤❤🎉 keep it Up ❤ and Big a Thumbs upp👍👍👍
Thank you, this video is very informative
honestly I was sceptical I would keep watching for long when I saw the goofiness in your intro (a little bit is funny, but man...), but you surprised me with some impressive knowledge and good explanations.
subbed for matching my safety standards related to junkyard science
informative and entertaining. well done
Awesome explanation!
You should make more videos about microcontrollers and make projects with explanation like this vid. Thanks!!!
great vide, thanks you very much. Greatting from Poland
Learn alot from you. Thank you!
Using an optocapler was an amazing idea. I liked a nice idea, my friend
A really good video👍
Thanks for the videos! I'm learning this stuff, but I'm not as advanced in this field like you are. I also play with Arduino and that is one of the reasons I'm interested in this project. I have FBT by: BSC 25-0278Q and I found the pins for input and the ground for the high voltage. I used a fluorescent bulbs' driver and I can get a very small discharge, but I'm interested in much more flames, like you demo here. At about 19:20 time marker, your spikes get much larger - what exactly did you do to achieve this? Have you changed the values on the Arduino sketch? Can you upload the Arduino sketch and exact schema you're using in this video?
great explainations. thanks
It always scares the crap out of me when transistors go bang! Hey this is the most reliable and controllable flyback driver I've ever used 320volt.com/en/uc3844-super-flyback-surucu/ you could tailor it for offline rectified mains by using the internal primary coil and a modern high voltage avalanche MOSFET and upping the current sense resistor to something like 0.5- to 1 ohms (experimentation might be needed but generally a 1 watt sized resistor should get pretty warm at full power but not roasting hot to touch).
The UC3845 version runs off 12v, there are 3842 and 3843 chips but they go all the way to 100% duty cycle and this could run the risk of popped mosfets as that inductive snubber needs deadtime to do its thing and reset.
That 220nF capacitor would probably need to be a lot smaller with rectified mains, maybe a few tens of nanofarad at most (old CRT boards will have them in the deflection circuit for salvage). Not sure about the 1.5uH inductor but it seems more to do more with timing than anything else.
If it's not stable put a 10 ohm resistor in series with that gate turnoff diode or omit altogether as it creates some high dv/dt multi-hundred volt voltage spikes on the drain which can couple back to the gate in via miller capacitance. Keep your scope probe away from the MOSFET drain unless you've got a probe rated for at least the breakdown rating of the MOSFET as if you crank the power pot too high it can start avalanching and clamps the drain voltage to its breakdown rating. eg a 600v avalanche rated fet will clamp voltage spikes across the drain and source to 600v by converting it to heat.
To monitor the drain voltage put a high impedance RCD snubber over it, say UF4007 fast recovery diode, 2.2nF 1kV ceramic capacitor and a 4.7-10 megohm resistor, now connect your voltmeter across the capacitor and it will give you the peak drain voltage so you can turn the power down if its close to exceeding the breakdown voltage rating of the MOSFET. Lower switching frequency = higher output voltage for a given number of primary turns and input voltage until the core starts complaining.
That big filter cap on the main power rail should be a low ESR type as the peak currents are large, but for rectified 120v it can be much smaller say one of those 220-470uF types you get in PC ATX power supplies. Watch out for inrush current with mains as it could blow your bridge rectifier or trip the breaker, NTC thermistor from an old SMPS should do the trick.
Correctly tuned this driver can produce enough output voltage to destroy the flyback so watch out when running it unloaded, also take note of all the earthing/grounding notes as the last thing you want is for a hv spark to find its way back into the driver and house wiring. Obviously with unisolated mains you can't ground the driver, but you can still ground the metal core clamp and return pin.
It was designed by jmartis2 here on youtube but let me know if you need any pointers, a tight circuit layout is critical with this one especially the IC, gate drive and current sense loop.
Awesome video; well done and very informative! Have you ever thought about using a two-switch flyback topology for driving a CRT flyback? You should see much cooler MOSFET temps and the other benefit is the back EMF from the flyback is clamped to the supply rails. That way you can get away with lower voltage MOSFETs which typically have lower RDSon parameters. The downside is the need for a GDT or a high-side driver IC, but the added complexity may prove to result in a more reliable circuit.
That just halves the individual switch frequency of each fet right? I dont see anything wrong with that. How could you offload the switch from the arduino to a hardware, dual switch oacillation?
You cannot clamp the "back EMF from the flyback" to the supply rail. That completely defeats the action of the circuit. The voltage on the input winding must be allowed to go to that determined by the output voltage and the turns ratio. This is the only important way in which the thing being called a transformer actually behaves as a transformer and it is a fundamental drawback of the topology. The ONLY thing you want to discharge is the small amount of energy stored in the leakage inductance and doing that with active circuity is complex, tricky and not worth the bother. A flyback converter isn't anything like a forward converter where active discharge of the primary is workable and sometimes worth the bother (versus adding a discharge winding).
@d614gakadoug9 You're 100% right in everything you said. Anecdotally, I built a relatively simple plasma speaker a few years back with a standard flyback topology. Worked well enough, but I would burn through FETs every so often. I tried a two-switch forward topology, mainly out of curiosity, not expecting much. The results were actually substantially better, at least in regards to music reproduction. Arc length was, as expected, a good bit smaller. YMMV. But yes, you're right; a forward topology is not really meant for driving a flyback. If you're curious, I think I have a video on my channel of that plasma speaker.
Really great video . I will sub for good learning ! 👍🏻💪🔥
You great teacher 😊 bro nice sharing
Electroboom 2.0?
Yes😂
Elctroboom comes to mind yes.
but 2.0? hmm
That intro made me laugh!
My Priorities:
1. Fun
2.learning
3. Safety
Would it be a good idea to put a potentiometer to this circuit? Then I could turn the potentiometer until the arc is the biggest, I would basically be tuning the circuit. But the lower resistance the lower frequency and when the ark turns white hot it could blow my transistor.
Many thanks ! I am glad by finding your presentation . If possible , explain CRT board role w/c found at the inlet of Cathode ray tub of cristal Tv , thanks again !
💥 wasn't expecting that 😅
👍
RELAXATION OSCILLATOR!! Subbed! XD
Transistors are dielectricaly coupled from base to collector.The most important difference is that for the common collector (that's the one with the load on the emitter side) you'll need a higher drive voltage. While for the common emitter 0.7 V is already enough, for the common collector the voltage must be 0.7 V + the voltage across the load.
DUDE......
I COULDNT MAKE IT PAST 3:50 BEFORE I QUIT.
I HAD TO STOP, LIKE SUBSCRIBE, AND COMMENT ON YOU BEING A QUALITY INSTRUCTOR, THE RARE BREED ON THE INTERNET.
YOU ARE THE ABOM79 OR JOE PIE OF ELECTRONICS.
im not blowing smoke either.
thanks for your work.
🇺🇸☯️♾😎🌵🌴🌲👍😁
excellent , tnx !📚📈🔬
I have a Sony multi-standard hi-res monitor that died after the flyback transformer failed. I cannot find a replacement part but could I create a replacement function?
Hey cheers for the video, out of curiousity can microwave transformer n HV cap drive a flyback?
No
Dont kill yourself with a microwave transformer pls
nice video thanks for the info. i just started posting videos to
Try triggering your waveform on the scope. Then the scope will adjust its time base automatically to display a waveform stable.
Why do some flybacks have 3 not 2 adjustment screw spots of which can turn?
Have you (or anyone else reading this) "played around" with using these flyback transformers in a HHO electrolizers? I've run into several "side references" to doing so; but, very little info on how to do it and safety measures needed ~ just that it (supposively, at least) greatly enhances the gas output, due to the HV & HF doing a better job breaking the convalescent bonds...
I'm about to build one.
Whenever I do it, everything works for about 3 seconds and the MOSFET burns out and heats up a lot, I don't know why, since the power supply provides a maximum of 2.5 A
Extreme High-voltage Transformer
Add capacitor to emitter to collector or drain to source
Will that help with the voltage spikes? Or what is that for
0:02 Another ElectroBOOM scene 😂😂😂
Super explanation, but don't deny, You got a shock of something You didn't expect to happen!? :)
Wouldn't You better use a sinewave to drive the transformer?
No. The thing being called a transformer is not used as a transformer for energy delivery. It stores energy as a magnetic field when current is flowing in the input winding and delivers that energy to the output circuit via the output winding when the current flowing in the input winding is turned off.
You deserve more audience, but it seems people prefer watching funny things. That's why I chose not to make videos, but I appreciate yours. Few people go into such details indeed.
is he a son of mr boom ? "mr electroboom"
I have built single transistor driver with feedback coil. It ran the best so far yet still not impressive. Constructed push pull driver arc is pathetic draws up to 6 amps at 10v and cant be ran for more than 20 seconds. Thinking of making isolated op amp driven two mosfet circuit if i cant figure out trans version. Any tips? I use it to make lichtenburg figures on wood.
Ps. Great video. Really liked waveform explanation. Also the difference between trans and mosfet driving requirements.
I've tried to make lichtenburg figures on wood before and using a neon sign transformer or a microwave transformer is probably the easiest way. However, if you want to make your own custom circuit I would experiment with the ZVS driver that uses two mosfets and can switch a lot of current, Ive had a lot of success connecting flybacks to ZVS drivers Ive made and you could potentially connect TWO flybacks to it if you require more voltage since the circuit can supply enough current. adammunich.com/zvs-driver/
I have some mots. I they work great for thick pieces of wood. However the flybacks dc output gives the ability to draw with the lightning. Also enhances the fine effects the voltage has the image. Only issue was not enough current out caused it to take a very long time to accomplish. Would the inductor value limit the overall current the circuit pulls. I need it to be able to run continuous. Also do know a good place to get NST?
Also how would u go about modulating for plasma speaker?
One good mod is to get rid of douche cap
👍 🙆🏽♀️soAfterAll,WeCanDriveTheMosfetInductiveLoadsWithThe555,WithTheRiskOfBurningThe555?
hahahahaa make more vids dude , u better than a lot out there on youtube, kudos
The camera quality 🤌
ZVS driver is better circuit to drive flyback transformer
Dude you can be a university professor
15,625 Hz
Electroboom from walmart:
Electroboom from Wish
Is he Jesse Pinkman!?
How in the flying fk are there only this many likes?!
There is absolutely no AC involved in a flyback converter circuit in terms of delivering useful power. Current flow is always unidirectional in both the input and output windings. You can get ringing that is AC but it doesn't play a role in power delivery.
It is pretty clear to me that he does not understand how a flyback circuit works.
Thumbs down for using the VAR instead the Trigger...
Just kidding. good video bro. Burning stuff is how you learn when you reach the limit.
But, seriously, for the sake of humanity use the Triggers.
copy of electro Boom 😂
When you use "profane" language and "swear" you express that you bleong to a "juncky" class. I watched your video to the end nd was surprized if it was necessary for you to swear. I did not dislike your video, but you have to think about it.
Stick and stones may brake my bones but swering ....
Wrong
They also work with pulsed DC.