I have seen many explanations on SMPS's, this is the first time I get the concept this clearly. Can't wait to see the second part! 8 people disliked this video are the SMPS manufacturers that wants you to buy a new one when yours get busted.
Thank you very kind I really appreciate it...but there is nobody else to blame than me for having not more ....
3 ปีที่แล้ว +2
@@TRXLab İ think that sometimes the growth of tech channels is slow, unless they use extensive amounts of clickbait or appeal to a wider audience who isn't interested in the details of the engineering behind products. İ am interested in your channel because i am a electrical engineering student at Cukurova University. Your videos help me to learn about electrical engineering without getting too much into the details. Thank you.
@@TRXLab "blame"?? There is no reason for blame. This is a very good amount of subscribers for someone who is at the far end of the learning curve. This isn't a channel for the rookies, they are on the other side of the learning curve, studying resistor color codes. Your viewers are the "big boys" and there aren't that many left in this "find a fault, then replace the module"-type world. This is a diagnosis channel, not a parts changer channel. Be proud!
Lot's of great information Peter. Not as easy as finding a cracked capacitor or resister by sight. Without basic knowledge you have no clue where to start. Thanks for taking the time to explain things like you do. 73 de KB7ICI. Looking forward to the next one.
Another video with great information, thank you so much for doing these again. It's great to have your content growing again, but life has to come first so please never worry about needing to take a break.
Awesome video Peter! Please feel free to repeat yourself as much as you want. Some sank in because of you repeating yourself. Looking forward to the next video on the repair. Happy New Year! Joel
Don't worry you can repeat yourself as many times as you want! That is good for me so I can understand better with repetitions. Good job sir. I love it. Thanks.
Peter millions of Thanks really did the best explanation than anyone Professor Peter You"re the Best! finally someone explained this well. I learned so much more than University, HVDC did not do as well as you do.
Thanks Peter! I have a SMPS for a Yaesu, Model# FP-757-GX, that I bought at a hamfest for $1 U.S. dollar. Of course it does not work, but I tried to diagnose it with no luck. I now know it is a 2 Transistor Forward Converter SMPS, so that is progress and gives me hope that one day I might have it working :) I am really looking forward to your next video on repairing these things.
I salute you first of all, Thanks for your effort and I shared your videos with my friends as a gratitude thanks again this video was great for me to enhance my knowledge in switching power supplies.. my Best regards
great video. Very timely for me. I have a jetstream smps which just died, got the schematic it is #4 half bridge push pull. started working but got side tracked with other things. Waiting for your next videos to start back on it. Keep the videos coming.
amazing explanations, and I think its a Half-Bridge push pull converter design as I see 3 big caps, 2 series ( the closer ones) and both parallel with the big cap behind the coil, but this is just guessing. thank you for this amazing video.
good approach but double check if the center of the two caps are in any way connected to the transformer coil as you can find it in the half bride design...
Since SMPS are the todays normal standards, this video has a high value for all those electronic aficionados out there! Fine video, Peter, thank you! Btw.. Ich bin EA Fanboy, sind hier in Viersen, eine Stunde entfernt, und haben einen super Support, ich bekomme ohne zögern selbst Unterlagen aus den 1980ern..ich habe hier viele Geräte, auch der 35 KG Klasse 100A ;-) 73 de Olaf
Thanks Olaf. Hope we get some light into the dark. To put that much information in one video is really a challenge...And yes EA is really a good brand...
A deep dive and I'm treading water. As you stated, finding a schematic or service manual has become almost impossible. I look forward to part II. Thanks Peter.
Hi Peter, das war ein interessanter Vortrag. Ich muss immer wieder SMPS reparieren (Flugzeugelektronik von Honeywell & Rockwell-Collins), habe mir aber über die verschiedenen Designs nie große Gedanken gemacht :-) Interessant wird es, sobald In-rush-current protection und PFC dazu kommen. Tip: SMPS prüft man von hinten nach vorne :-) Ohne einstellbare P/S für AC (Spannung und Frequenz einstellbar) und DC (bis zu 400 VDC!) und einer electronic load bin ich da völlig aufgeschmissen. Und ja, ich muss nach der Reparatur diverse Prüfungen durchführen bevor das P/S wieder fliegen darf.
@@TRXLab Einfache SMPS mit Gleichrichter, Kondensator, Schalter, und Trafo mit mehreren Sekundärkreisen, von denen einer, meistens der 5V- (PC) oder 12V-Kreis (Afu-PS), geregelt wird, sind tatsächlich recht einfach zu reparieren. Obwohl gerade hatte ich recht simples SMPS, da wollte auch der U2844 nicht loslaufen, weil der COMP-Ausgang (Error) durch ein Problem in der power-good-Erkennung auf 0,7 gehalten wurde. Ich habe da ein sehr aufwändig gestaltetes SMPS mit inrush current protection, aktiver PFC (eigener Regler mit Transistor als schaltbare Last) und mehreren "sekundären" SMPS-Schaltungen, deren Regler eine gemeinsame DC-Versorgung haben. Leider darf ich keine Schaltbilder öffentlich machen (intellectual property). Da muss ich erst sicherstellen, dass die PWM-Regler laufen und alle Gates der Schalter mit dem PWM versorgt sind. Dann ist da ein Regler, ich glaube es ist der für die PFC, der erst dann eine PWM erzeugt, wenn bestimmte Eingangbedingungen erfüllt sind. Da beisst sich dann die Katze in den Schwanz und dreht sich im Kreis. Es kommt dann auch das regelbare DC-Netzteil zum tragen, mit dem ich 200 VDC auf den Zwischenkreis-C gebe und prüfe das die sekundären SMPS funktionieren. Wenn der Test ok ist, dann DC weg und das 115V/40Hz-PS kann langsam hochgedreht werden. Irgendwann fängt auch die PFC an zu arbeiten. Dieses komplexe Teil wurde mir praktisch vor 2 Jahren auf den Tisch gestellt und ich lerne immer noch Neues :-)
I think that if I were repairing this unit, I would replace every Electrolytic capacitor with new High Temp, Low ESR, new capacitors. Not that it would be the source of the problem, but because it would make me feel that it was safer and more reliable to do so. It will be interesting to see what the actual source of the failure is, and Peter is the man to find it.
Thanks so much or all your help. I have an Icom IC-7800 and they use a Futaba FP2346C 3rd party SMPS board. Icom expects you to replace the board as an FRU so they won't provide me the schematic. I've not heard anything back from Futaba. I once repaired an older Icom transceiver (I don't recall which model) for a hospital's radio room. The power supply failed and I simply shot gunned all of the electrolytic capacitors and that brought it back to life. Unfortunately that is not the problem with the IC-7800. Hopefully your series of videos on the subject will help me out. Thanks again.
REPETITION is the key to effective instruction. The key to effective instruction is repetition. Do you know what the key is to effective instruction? Great introduction. I look forward to the next part. Thank you. Much appreciated.
Peter you are amazing knowledgeable engineer it is so amazing of the different types of power supplies and thank you for sharing with us such knowledge in your teaching Peter does all electronic circuits need full wave DC on both + and -
Its an interesting lesson indeed. Thank you. I have a SMPS in a bluetooth speaker system. I suspect a heavy load of current has invaded it due to lightening. Now the fuse gets blown repeatedly. I understand that is how the circuit is protected by the system from further damager. Can you please advise me what components I should particularly inspect to troubleshoot this problem. Appreciate your advice.
Great video. In the future could you do a video on how to do some home brew negative supplies? Simple circuits used in radios to create a negative 9 volts for ALC circuits and op amps? Charge pumps?
Thanks for taking the time to do your videos. I like them. You mentioned ham radio and I have seen your many videos on the subject. I intend to watch them ater I watch the power supply ones. What's your call sign? Mine is W8YI.
I have repaired Welding machines (invertors) that have full-bridge push-pull convertors, very common i believe even for the smallest (140amp welder) . Also the transistors are driven by a transformer-coupled gate drive circuits, i think i spotted the same transformer-coupled drive circuit on the psu schematic you showed here. Nice video breaking down these circuits! For the flyback is it worth noting the transformer dot for polarity?
Thanks for your feed back! The transformer is not a normal transformer, because its function is to store energy during the on time of the transistor and to deliver this energy during the off time via the diode to the secondary capacitor. So the transformer is a storage inductor with a primary and secondary winding. To store energy the transformer core needs an air gap and normal transformers do not have an air gap.
It's a two transistor forward convertor because both ends of the transformer are connected to the fets not one end connected to the center point of the electrolytics.
Are you German? I am, and my name is Frank Reiser. I am surprised that the cable plugs are not on the front panel. Can a switch mode power supply be variable in terms of output voltage as linear voltage supplies can be made? You are helping me get ready for my job interview repairing SMPSs. Wish me luck.
Looking at the schematic I think it's a two transistor forward converter? I'm not up on switch mode power supplies so I'll find this interesting to watch.
I've already saw one video on repair of exactly this model of PSU. The problem was in that small red inductor. It had broken wire. As I can see from the schematic, this one in particular has 2-transistor forward topology. Also, on schematic you can't see PFC circuitry, but, when we look one that's on table, we can see there's PFC choke, also, there's Motorola IC on main board (MC something).
Looks like two transistor forward converter as the transistors seems to switch together. First check fuse. Then check DC on both sides of L2. Next is to find out why there are no switching puls on the gates.
i want help! i bout a cheap computer smps perfectly normal volt output! the switching transistor starts to heat in idle itself draws 0.03 amp and 230v in idle !! what may be the cause of smps heating transistor 13007
@TRX Lab Are you able to share the document that outlines the different SMPS designs you showed in your video? I am going with a guess that this is a half-bridge push pull design!??
Peter I have some questions about the output stage capacitors. Should I wait to ask my questions or ask them now. Let me know I don't want to get a head of myself on this one. *Cheers* *73*
All my Switching powersupplys goes dead after max 3 years.. Then on Output line i have measure 85Volts.. My Icom has fast react and has not destroyed by luck. The Problem is when the Transistor goes down, he can bring high Power output.. atm i use an very old tranformator, there runs since 45 years.
yeah a lot of cheep SMPS's are crap but even high quality ones are working at its limit at a point. So it is no wonder that they quit earlier than linear's...
@Karstan Schulz - I have a switching power supply, that was built in 1998, and it is still functioning today. It runs 24 hours per day and 365 days per year.
@@vtorsi610 Yes my Commodore Amiga PowerSupply is from 1987 work's too.. The time of inductor winding is off.. on SpaceStation no trafo are running , the icom Switching pwr supply cost atm ~400Euros ^^
I would like to know what it is about each switching topology that determines their power range. So for example why is the flyback limited to 300w whereas the full bridge is many kilowatts. It's not obvious to me from the diagrams.
I was wondering the same thing. My guess would be a TDP of a transistor. That fast switching of big currents makes a lot af heat on the mosfets. Since in flyback you have just one transistor you must limit the max current or it would overheat. Full bridge has 4 transistors and not all are turned on at the same time so all that heat can spread more evenly. That is my only idea looking at the diagrams...
A very good question and at the same time a very complex one and as we all know there are no easy answers to complex issues. So to explain it all in detail it takes a semester at college. But the short one is 1. More transistors can mange more power than one. 2. We use different transformers with a different physical behaviour 3. heat dissipation, core size and heat sink is an issue. 4. wight and size and cost of transformers and chokes is an issue too 5. radio interference and power factor correction needs to be considered 6. more and more we need to reduce the total harmonic distortion which gets back in the line and creates a lot of problems to other devices. So we could list some more points and you may understand that this is really a complex issue development departments facing to get all in balance...
In a flyback converter, the transformer is really acting as a "coupled inductor". It's basically the same thing as a boost converter but with two inductors acting as one. That means that the energy that is transferred from input to output is stored entirely in the transformer at some point in the switching cycle. In forward/half-bridge/full-bridge/push pull topologies (which are more similar to buck converters), the transformer is actually acting as a transformer, not as an energy storage device, so it just scales voltage/current by the turns ratio. This has a few implications. For one, you need a transformer that is designed to store the energy rather than just transform it, which imposes some limitations. For another, because you're using the flyback effect to transfer the energy, you have big voltage/current stresses on your switching devices (input FET(s), output diode/FET). And lastly, you have to deal with the leakage inductance of the transformer - some of the energy doesn't go to the output but instead gets dumped back into the input, so you need to absorb/redirect it in a way that doesn't damage your components, using either a snubber (higher dissipation) or an active clamp (extra complexity). As your transformers get bigger, you tend to get more leakage as well, so your efficiency starts being more of an issue. So at some point all the extra complexity needed to address the shortcomings of the flyback topology outweighs its simplicity, and other topologies start becoming more competitive.
@@marcelbirthelmer7941 You should do a TH-cam presentation on this particular issue in more detail if you haven't already. I think you'd be good at it.
@@TRXLab Linear transformer is easy to measure and identify the primary and secondary side. Is there a way to test a pulse transformer to identify its parameters and what circuit it is designed to run?
You talk *ALOT* about nonsense... I can tell you have alot of knowledge about this topic.. some areas only need to be summarized with the important facts.. or show how to test.. period.. i do appreciate the videos.. i want to learn.. but i feel like this is such long winded.. i'm sorry...
![[HIGHLIGHT] หมีLIVEปะ? | EP.171 เห็นแต่ในจอ วันนี้มาต้องขอคารวะ](http://i.ytimg.com/vi/gPWLxa0e_Z8/mqdefault.jpg)
Peter is an amazing and talented man. We are so lucky he shares his knowledge and talents with us. Thank you Peter.
Totally agree with you
i guess I'm kind of randomly asking but does anybody know a good place to stream new series online ?
@Santino Kameron i watch on flixzone. You can find it on google =)
@Santino Kameron i watch on flixzone. Just google for it :)
It is just so good to have videos from Peter again!
This video plus 79 and 80 should be in a playlist :)
Thanks for the time that you spend with us.
I have seen many explanations on SMPS's, this is the first time I get the concept this clearly. Can't wait to see the second part! 8 people disliked this video are the SMPS manufacturers that wants you to buy a new one when yours get busted.
Thank you Bora!
i wish you had more subscribers. İ think that you deserve it for the effort you are putting in for teaching us.
Yes i agree in my opinion Peter is by far the best to explain and show regarding electronics.
Thank you very kind I really appreciate it...but there is nobody else to blame than me for having not more ....
@@TRXLab İ think that sometimes the growth of tech channels is slow, unless they use extensive amounts of clickbait or appeal to a wider audience who isn't interested in the details of the engineering behind products. İ am interested in your channel because i am a electrical engineering student at Cukurova University. Your videos help me to learn about electrical engineering without getting too much into the details. Thank you.
@@TRXLab "blame"?? There is no reason for blame. This is a very good amount of subscribers for someone who is at the far end of the learning curve. This isn't a channel for the rookies, they are on the other side of the learning curve, studying resistor color codes. Your viewers are the "big boys" and there aren't that many left in this "find a fault, then replace the module"-type world. This is a diagnosis channel, not a parts changer channel. Be proud!
Thanks Peter! The SMPS fog is starting to clear. Can't wait for part II.
Happy New Year!
73s Tom
Lot's of great information Peter. Not as easy as finding a cracked capacitor or resister by sight. Without basic knowledge you have no clue where to start. Thanks for taking the time to explain things like you do. 73 de KB7ICI. Looking forward to the next one.
Another video with great information, thank you so much for doing these again. It's great to have your content growing again, but life has to come first so please never worry about needing to take a break.
Nice to see you back Peter! All the best in 2021!
Excellent video. I've learned a lot already and looking forward to part two. Thanks.
Awesome video Peter! Please feel free to repeat yourself as much as you want. Some sank in because of you repeating yourself. Looking forward to the next video on the repair. Happy New Year! Joel
Thanks Joel! HNY
Great work Peter! Looking forward to the rest of the story!
73's, Jim.
Don't worry you can repeat yourself as many times as you want! That is good for me so I can understand better with repetitions. Good job sir. I love it. Thanks.
Great video. Cant wait for the next videos. Thanks Peter.
Peter millions of Thanks really did the best explanation than anyone Professor Peter You"re the Best! finally someone explained this well. I learned so much more than University, HVDC did not do as well as you do.
Awesome!!! I wake up and see TRX video with Peter...the day just got better
Peter I wish you a very prosperous new year
73 from Jeff de WD8JM
lol thank you Jeff! Happy New Year
Great channel. Learned a lot from you. Thanks!
Thanks Peter. Looking forward to putting theory into practice in video #2 👍🏻 Yes, got to the end 😀
Your explainations are very good and gives a great understanding of the designs, love it thank you for your time and video 73
Great in depth delve into the modern SMPS but described in a way that anyone can understand, excellent video Peter 👍.
Thank you!
Great to see you Peter. Happy New year!
Good to see you George! Have a very Happy New Year
@@TRXLab Can we expect to see some regular content from you in 2021 Peter?
I did learn alot of this, power supplys was just a mess for me but you cleared up this very well🙂 very good video as always 👍
Great to see you again and hope that you have a great 2021
Happy New Year
Incredibly helpful. Thank you Sir.
I felt like a good lecture after my college days,thanks Peter ,.73s ,waiting for more
Thanks for another great video Peter
Thanks Grant and good to see you!
Thanks for all detailed explanation
Thanks Peter! I have a SMPS for a Yaesu, Model# FP-757-GX, that I bought at a hamfest for $1 U.S. dollar. Of course it does not work, but I tried to diagnose it with no luck. I now know it is a 2 Transistor Forward Converter SMPS, so that is progress and gives me hope that one day I might have it working :)
I am really looking forward to your next video on repairing these things.
Excellent explanation. Thanks a lot.
Thank you. Very useful video!
I salute you first of all, Thanks for your effort and I shared your videos with my friends as a gratitude thanks again this video was great for me to enhance my knowledge in switching power supplies.. my Best regards
Thank you, glad that you like the video..
great video. Very timely for me. I have a jetstream smps which just died, got the schematic it is #4 half bridge push pull. started working but got side tracked with other things. Waiting for your next videos to start back on it. Keep the videos coming.
ah keep us posted if you was able to fix it. >Part 2 video is almost ready.
We are waiting for the 2nd part of this episode...happy new year !
Minions rule!
we are working on it HNY
amazing explanations, and I think its a Half-Bridge push pull converter design as I see 3 big caps, 2 series ( the closer ones) and both parallel with the big cap behind the coil, but this is just guessing.
thank you for this amazing video.
good approach but double check if the center of the two caps are in any way connected to the transformer coil as you can find it in the half bride design...
Very informative video sir
Thanks Peter 👍🇬🇧❤️
Nice and straight forward explantion. All the best and happy new year.
Thank you and Happy New Year
trx bench,,,now trx lab great video
hope that will now not so much confuse with TRX training ???
Happy New Year Peter, tnx great info on the dark art of SMPS
Happy New Year
Sehr gut. Vielen dank.
Since SMPS are the todays normal standards, this video has a high value for all those electronic aficionados out there! Fine video, Peter, thank you! Btw.. Ich bin EA Fanboy, sind hier in Viersen, eine Stunde entfernt, und haben einen super Support, ich bekomme ohne zögern selbst Unterlagen aus den 1980ern..ich habe hier viele Geräte, auch der 35 KG Klasse 100A ;-) 73 de Olaf
Thanks Olaf. Hope we get some light into the dark. To put that much information in one video is really a challenge...And yes EA is really a good brand...
Hello Peter - Thank you for such a great video. Very informative.
73 de EI6DP
Thank you, glad that you liked it
A deep dive and I'm treading water. As you stated, finding a schematic or service manual has become almost impossible. I look forward to part II. Thanks Peter.
yeah you are right unfortunately no service manuals..
Hi Peter, das war ein interessanter Vortrag. Ich muss immer wieder SMPS reparieren (Flugzeugelektronik von Honeywell & Rockwell-Collins), habe mir aber über die verschiedenen Designs nie große Gedanken gemacht :-) Interessant wird es, sobald In-rush-current protection und PFC dazu kommen. Tip: SMPS prüft man von hinten nach vorne :-) Ohne einstellbare P/S für AC (Spannung und Frequenz einstellbar) und DC (bis zu 400 VDC!) und einer electronic load bin ich da völlig aufgeschmissen. Und ja, ich muss nach der Reparatur diverse Prüfungen durchführen bevor das P/S wieder fliegen darf.
Ah sehr interesanter Bericht! Vielen Dank. Warum prüfst Du von hinten was ist deiner Meinung der Vorteil?
@@TRXLab Einfache SMPS mit Gleichrichter, Kondensator, Schalter, und Trafo mit mehreren Sekundärkreisen, von denen einer, meistens der 5V- (PC) oder 12V-Kreis (Afu-PS), geregelt wird, sind tatsächlich recht einfach zu reparieren. Obwohl gerade hatte ich recht simples SMPS, da wollte auch der U2844 nicht loslaufen, weil der COMP-Ausgang (Error) durch ein Problem in der power-good-Erkennung auf 0,7 gehalten wurde.
Ich habe da ein sehr aufwändig gestaltetes SMPS mit inrush current protection, aktiver PFC (eigener Regler mit Transistor als schaltbare Last) und mehreren "sekundären" SMPS-Schaltungen, deren Regler eine gemeinsame DC-Versorgung haben. Leider darf ich keine Schaltbilder öffentlich machen (intellectual property).
Da muss ich erst sicherstellen, dass die PWM-Regler laufen und alle Gates der Schalter mit dem PWM versorgt sind. Dann ist da ein Regler, ich glaube es ist der für die PFC, der erst dann eine PWM erzeugt, wenn bestimmte Eingangbedingungen erfüllt sind. Da beisst sich dann die Katze in den Schwanz und dreht sich im Kreis.
Es kommt dann auch das regelbare DC-Netzteil zum tragen, mit dem ich 200 VDC auf den Zwischenkreis-C gebe und prüfe das die sekundären SMPS funktionieren. Wenn der Test ok ist, dann DC weg und das 115V/40Hz-PS kann langsam hochgedreht werden. Irgendwann fängt auch die PFC an zu arbeiten. Dieses komplexe Teil wurde mir praktisch vor 2 Jahren auf den Tisch gestellt und ich lerne immer noch Neues :-)
Perfect ..👍..
You make TH-cam worthwhile
Thank you!
Thanks for this vedio
I think that if I were repairing this unit, I would replace every Electrolytic capacitor with new High Temp, Low ESR, new capacitors. Not that it would be the source of the problem, but because it would make me feel that it was safer and more reliable to do so.
It will be interesting to see what the actual source of the failure is, and Peter is the man to find it.
That is basically not wrong for a unit 25+ years but I'm almost sure that the high quality caps used are still good...
@@TRXLab Maybe, but in a SMPS the caps are highly stressed by the switching pulses and therefore prone to accelerated aging
Thank you peter. Your SMPS is a double transistor forward converter with galvanic isolation feedback
correct :-)
Thanks so much or all your help. I have an Icom IC-7800 and they use a Futaba FP2346C 3rd party SMPS board. Icom expects you to replace the board as an FRU so they won't provide me the schematic. I've not heard anything back from Futaba. I once repaired an older Icom transceiver (I don't recall which model) for a hospital's radio room. The power supply failed and I simply shot gunned all of the electrolytic capacitors and that brought it back to life. Unfortunately that is not the problem with the IC-7800. Hopefully your series of videos on the subject will help me out. Thanks again.
REPETITION is the key to effective instruction. The key to effective instruction is repetition. Do you know what the key is to effective instruction? Great introduction. I look forward to the next part. Thank you. Much appreciated.
Peter you are amazing knowledgeable engineer it is so amazing of the different types of power supplies and thank you for sharing with us such knowledge in your teaching Peter does all electronic circuits need full wave DC on both + and -
Thank you John!
Its an interesting lesson indeed. Thank you. I have a SMPS in a bluetooth speaker system. I suspect a heavy load of current has invaded it due to lightening. Now the fuse gets blown repeatedly. I understand that is how the circuit is protected by the system from further damager. Can you please advise me what components I should particularly inspect to troubleshoot this problem. Appreciate your advice.
"Repetition is the mother of all learning"
Great video. In the future could you do a video on how to do some home brew negative supplies? Simple circuits used in radios to create a negative 9 volts for ALC circuits and op amps? Charge pumps?
should be possible for a future project if we find time...
Thanks for taking the time to do your videos. I like them. You mentioned ham radio and I have seen your many videos on the subject. I intend to watch them ater I watch the power supply ones. What's your call sign? Mine is W8YI.
Keep repeating, works for me
Thank you
Thanks for watching
Excellent presentation. Will you include the pdf of the different designs in the follow up videos please.
I have repaired Welding machines (invertors) that have full-bridge push-pull convertors, very common i believe even for the smallest (140amp welder) . Also the transistors are driven by a transformer-coupled gate drive circuits, i think i spotted the same transformer-coupled drive circuit on the psu schematic you showed here. Nice video breaking down these circuits! For the flyback is it worth noting the transformer dot for polarity?
Thanks for your feed back!
The transformer is not a normal transformer, because its function is to store energy during the on time of the transistor and to deliver this energy during the off time via the diode to the secondary capacitor. So the transformer is a storage inductor with a primary and secondary winding. To store energy the transformer core needs an air gap and normal transformers do not have an air gap.
It's a two transistor forward convertor because both ends of the transformer are connected to the fets not one end connected to the center point of the electrolytics.
Are you German? I am, and my name is Frank Reiser. I am surprised that the cable plugs are not on the front panel. Can a switch mode power supply be variable in terms of output voltage as linear voltage supplies can be made? You are helping me get ready for my job interview repairing SMPSs. Wish me luck.
Yes, variable voltage is possible to some degree. Output Voltage stability and ripple need to be considered.
Looking at the schematic I think it's a two transistor forward converter? I'm not up on switch mode power supplies so I'll find this interesting to watch.
good guess
Peter, were you ever an electronicsTeacher? You would be great.
No never..
@@TRXLab Well thank goodness for that...
I've already saw one video on repair of exactly this model of PSU. The problem was in that small red inductor. It had broken wire. As I can see from the schematic, this one in particular has 2-transistor forward topology. Also, on schematic you can't see PFC circuitry, but, when we look one that's on table, we can see there's PFC choke, also, there's Motorola IC on main board (MC something).
may be that you have seen my video with an open solder joint at the driver transformer?
@@TRXLab yes. Right aftre I wrote that cpmment, I've seen it on your channel. Great videos, both. Thanks for uploading such a good tutorial.
Looks like two transistor forward converter as the transistors seems to switch together. First check fuse. Then check DC on both sides of L2. Next is to find out why there are no switching puls on the gates.
Peter is the best in field
Thank you
Hallo Peter,
Vielen Dank für das Video. Könnten Sie uns das Dokument bitte mitteilen?
i want help!
i bout a cheap computer smps perfectly normal volt output!
the switching transistor starts to heat in idle itself
draws 0.03 amp and 230v in idle !!
what may be the cause of smps heating
transistor 13007
@TRX Lab Are you able to share the document that outlines the different SMPS designs you showed in your video? I am going with a guess that this is a half-bridge push pull design!??
double check if the cap voltage-divider is some how connected to to one of the primary transformer leads??
Peter I have some questions about the output stage capacitors. Should I wait to ask my questions or ask them now. Let me know I don't want to get a head of myself on this one. *Cheers* *73*
may be better to wait until part 2 and questions might already be answered. But if you can't wait feel free and ask
@@TRXLab I will wait till latter to ask my question, Hint: output stage capacitors
Thank you man❤️❤️❤️🌹. How I can find pdf (design.....) you used?
Can you please share the powerpoint file that you went through here?
Is there already video about controller circuit?
video #212 and #213
Hello...
I hope you will about PFC currently present in smps.
Power factor correction is not planned in this series as we need first to get the basics over.. I will think about it for a future project..
All my Switching powersupplys goes dead after max 3 years.. Then on Output line i have measure 85Volts.. My Icom has fast react and has not destroyed by luck.
The Problem is when the Transistor goes down, he can bring high Power output.. atm i use an very old tranformator, there runs since 45 years.
yeah a lot of cheep SMPS's are crap but even high quality ones are working at its limit at a point. So it is no wonder that they quit earlier than linear's...
@Karstan Schulz - I have a switching power supply, that was built in 1998, and it is still functioning today. It runs 24 hours per day and 365 days per year.
@@vtorsi610 Yes my Commodore Amiga PowerSupply is from 1987 work's too..
The time of inductor winding is off.. on SpaceStation no trafo are running , the icom Switching pwr supply cost atm ~400Euros ^^
I would like to know what it is about each switching topology that determines their power range. So for example why is the flyback limited to 300w whereas the full bridge is many kilowatts. It's not obvious to me from the diagrams.
I was wondering the same thing. My guess would be a TDP of a transistor. That fast switching of big currents makes a lot af heat on the mosfets. Since in flyback you have just one transistor you must limit the max current or it would overheat. Full bridge has 4 transistors and not all are turned on at the same time so all that heat can spread more evenly. That is my only idea looking at the diagrams...
A very good question and at the same time a very complex one and as we all know there are no easy answers to complex issues. So to explain it all in detail it takes a semester at college. But the short one is
1. More transistors can mange more power than one.
2. We use different transformers with a different physical behaviour
3. heat dissipation, core size and heat sink is an issue.
4. wight and size and cost of transformers and chokes is an issue too
5. radio interference and power factor correction needs to be considered
6. more and more we need to reduce the total harmonic distortion which gets back in the line and creates a lot of problems to other devices.
So we could list some more points and you may understand that this is really a complex issue development departments facing to get all in balance...
In a flyback converter, the transformer is really acting as a "coupled inductor". It's basically the same thing as a boost converter but with two inductors acting as one. That means that the energy that is transferred from input to output is stored entirely in the transformer at some point in the switching cycle. In forward/half-bridge/full-bridge/push pull topologies (which are more similar to buck converters), the transformer is actually acting as a transformer, not as an energy storage device, so it just scales voltage/current by the turns ratio.
This has a few implications. For one, you need a transformer that is designed to store the energy rather than just transform it, which imposes some limitations. For another, because you're using the flyback effect to transfer the energy, you have big voltage/current stresses on your switching devices (input FET(s), output diode/FET). And lastly, you have to deal with the leakage inductance of the transformer - some of the energy doesn't go to the output but instead gets dumped back into the input, so you need to absorb/redirect it in a way that doesn't damage your components, using either a snubber (higher dissipation) or an active clamp (extra complexity). As your transformers get bigger, you tend to get more leakage as well, so your efficiency starts being more of an issue.
So at some point all the extra complexity needed to address the shortcomings of the flyback topology outweighs its simplicity, and other topologies start becoming more competitive.
@@marcelbirthelmer7941 You should do a TH-cam presentation on this particular issue in more detail if you haven't already. I think you'd be good at it.
@@TRXLab Linear transformer is easy to measure and identify the primary and secondary side. Is there a way to test a pulse transformer to identify its parameters and what circuit it is designed to run?
Tell Siemans and ABB of Sweden how to explain smps
First
What's all that equipment used for
what do you mean??
thanks peter can you upload the documents about the smps so i can download ?
not yet but I'm working on that
@@TRXLab ok good luck .. thank you ❤
I also would love to have a copy of that presentation
Viel Erfolg.İch bin dabei SMPS Hochspannungsnetzteil zu bauen.Ob Sie diese Video in Detschersprache erhältlich ist?Danke tür İhre mühe im Voraus.
Nein leider nicht, sorry
Hallo, Danke für das tolle Video. Ich hätte gerne das Word Dokument, weil es so übersichtlich gemacht ist. Kann ich mir das irgendwo downloaden ?
Nein leider nicht, tut mir leid
Alles klar. Danke für die Antwort. @@TRXLab
a long time you have not done vedio what happens my friend
video #208 in the comment section under the video you find an answer on that..
31:37
perfect!
You talk *ALOT* about nonsense... I can tell you have alot of knowledge about this topic.. some areas only need to be summarized with the important facts.. or show how to test.. period.. i do appreciate the videos.. i want to learn.. but i feel like this is such long winded.. i'm sorry...
What a Pile of Incoherent Babbling