I once tried prototyping a 1A buck LED driver that operates at around 1 MHz on a bread board. This ultimately drove me to begin my bachelor's degree in electrical engineering because I had no idea why the heck this just wouldn't work! Today I do know why... =D
@@After_Tech_Industries To be honest, I never actually checked what was the problem. So "Today I have some ideas why" would have been more correct. I think the main reason was the high contact resistance in the bread board contacts along the high frequency, high current path. I think the losses there probably screwed up the feedback loop of the regulator. Another probable problem was that the MIC2301 driver chip that I used has an integrated high side switch and therefore its SOIC8 package has an ePad at the bottom for cooling. The SOIC adapter board I used didn't connect to that, of course. I think it then also overheated way more quickly than I expected.
In my case I ultimately put it in a box in an attic and forgot all about it. I got an output but it was inefficient and oscillating. Without an oscilloscope its not worthwhile to design an SMPS at home.
I was researching the different topologies to decide which one to design a low-voltage DC UPS around, and kept hearing that SEPIC is unstable against transient loads. It'd be interesting to see a video on how different topologies react to different types of loads.
Hey sounds like the situation I found myself in too! Surprised there isn't more commercial options around this given how often you'd think home users would just want an uninterrupted DC power source for their home network and other DC-powered electronics. My setup at the moment is a small server rack with a 15V DC PSU and a 12V Lead Acid battery (+ battery tender) with their ground connections tied. The output voltages are separated by diodes, thus creating a sort of "OR-ing" device. That gate's output is connected to a powerpole rigrunner so that I can split all my components to separate SEPIC converters to ease the change in load and to also not have a single point of failure. So far so good but then again I'm only running raspberry pi's, switches, and a router at the moment.
My experience is any SMPS will be unstable with transient loads. Go ahead and use one, but either have a huge cap, a battery or some other stable transient source to keep it from blowing out your electronics, or add a linear low-drop-out regulator at the end. It could even run saturated for low loss, but will prevent the voltage from going too high. That said, I suspect this SEPIC is worse than most SMPSs.
Many power supplies are based on a dual control loop topology, with an outer loop with conventional voltage control PWM and inner loop based on current mode control. This tends to protect the power supply against transient loads, especially short circuits and the like. Something like UC3843 and like series of chips may be more stable with a SEPIC converter. There is a sense resistor in series with the source of the switch to control switch currents, and there is an outer control loop that senses the voltage.
@@chaosdragon6718 These are the reasons I moved away from SEPIC topology. I'm currently exploring flyback and push-pull, but stepping from designing buck converters to these more advanced topologies is pretty daunting.
Your videos are truly informative. It provides me with a lot of electronics knowledge as a hobbyist. Keep going. Also get well soon. You are great, scott :)
Sure, they're very nice. But I think there's an error on the schematics presented for the DIY SEPIC (on 10:20): there's no connection to gnd for Q1 (and L2, C4, C5).
What I like about this design is the "self destruct" protection capability: One of my biggest fears when using Buck Converters specifically is that, when the switching transistor fails, it will most likely go shortcircuit (which in buck converters means the full input voltage will get to the output) destroying the load with overvoltage. In contrast, this design will not only let the voltage go low but also may just blow a fuse or trigger an overcurrent protection. This feature/bug is also present in synchronous buck converters: if one transistor fails, as soon the second one turns on, the whole thing will just go shortcuit and trigger a protection system before the output voltage can get high enough to kill the load. But maybe I've too much of a green mind for a disposing culture society?
Why wouldn’t you use flyback/forward topologies? They require only an extra coil, which is nothing. But instead offer useful p/s ratio and an isolation level
@@sc0or Absolutely! In some cases using flyback/forward types are just too bulky, some devices do not require it. computers, graphics cards, perhaps? Also, high efficiency isolated supplies are more expensive to build, specially for small form factors. But yes! I absolutely agree with that! I love isolated supplies, they come with so many benefits
SEPIC converters are great for applications where the output power is low. For higher power applications, there is the two-switch non-inverting buck-boost converter. It is simply a combination of a buck and a boost converter. When the input voltage is higher than the output, it holds the “boost” switch open and modulates the “buck” switch. When the input voltage is lower than the output, it holds the “buck” switch closed and modulates the “boost” switch.
Great video Scott! I suspect your ferrite toroid had issues due to saturation, due to the uni-directional currents in it. Either add a small gap by using a multi part core, or go with high permeability powdered iron.
I have alot of experience with SEPIC and Cuk converters. Coupled inductors are great. They can be more efficient (alot of variables there though), they have better dynamics (dual inductor SEPICs and Cuks have some high frequency resonance that can make compensation harder), and the overall solution size can be smaller than for dual inductors. What I've seen is for name brand (like Coilcraft and Wurth) inductors, prices are comparable between two singles and a coupled. But the market for singles is bigger, so its easier to find other manufacturers of singles. Also, worth pointing out that I've heard Dr Cuk is adamant that a Cuk converter built with a coupled inductors isn't really a Cuk converter.
@@Blox117 It's named for en.wikipedia.org/wiki/Slobodan_%C4%86uk . Funny name perhaps, but he's Serbian, that is his name, and that is indeed what it's called.
dude, the sepic is noesing as fk, but i have to use it, how to reduce the ripple to 5mv under 12v at 3a? i have tried everything........rc lc re apsorbtion, comm choke, what i did wrong? it keep around 100mv at 1a ar 12v, i cant knock it down further.......
Is this commercial Buck converters are coming with close loop control (I mean, is it change its duty according to the change in output voltage? As we know, the output voltage may change with change in load. Please, give your thoughts.) Thanks, in advance
That sounds like a constant current/constant voltage (CC/CV Buck) converter. The LM5117 is just one example, but I bought some cheaper ones from Amazon years ago because I needed constant current control for running LEDs. They use feedback loops to monitor current & voltage.
What happens to efficiency if you make it synchronous? I’d think you’d get it way more efficient. I’d love to see more videos on boost/buck with ultra high efficiency for sure.
Synchronous 4-switch devices are much more efficient and can handle much higher currents. Of course the down side is that they are much more expensive and are also becoming quite hard to find. My preference for stable voltages with very little ripple are ones based on the LTC3780, the output is so stable that I have very successfully used them for mobile radio, something which is near impossible with most non-linear converters. I realised early on that Sepic devices would not be adequate.
@@chrishartley1210 ya a full bridge is a solution but the problem with full bridges is that they require p channel high side which means you can’t use ganfets. I’m wondering if sepic with the diode replaced with another fet woold get you to n channel nirvana.
Just make a playlist called, "How Does It Work?". Desolder parts off of boards and slowly walk us all through the process. This could be even better than all of your current content. Perhaps, just make a new channel for it ??
Meh... SEPIC isn't the best buck-boost converter... Yeah, it's the simplest, but the 4 switch buck-boost converter it's the better one, unless you need an insulated one.
Clickbait title. There is NO ONE who is trying to keep this a secret. GreatScott is good technical information and well communicated, Including this one. But AAARGH, MISLEADING CLICKBAIT IS SUCH A DAMN PLAGUE! I routinely put "SECRET" or "THEY DON'T WANT YOU TO KNOW" etc in my 'don't ever recommend this channel again' bucket. And almost did on this one before I saw who it was from.
nice, often i see boost buck and sepics being combined IC that efficiency seems low tho at 60% a LDO may be better ( if it is lowering) Also maybe make a video about the energy efficiency of all those converters .
I love using SEPIC in my designs. The biggest benefit is that they are inherently failsafe, there is no fault mode in which the input voltage can be on the output. Also if you need positive and negative rails, you can use the same regulator chip for SEPIC and inverting.
There is a chance yes, but if I remember correctly from Siemens’ SN29500 the chance is relatively small. And then you can split up C1 to make the design even more robust.
I found a moderately high power (5a or 60w) buck/boost converter. What I found was a decrease in efficiency, increase in heat. My aim was to power 4g modem/router on boats, which operates in high temperatures (on sea, on summer, in Turkey). Boats are like cars, while engine is running voltage contains lots of jitter due to charging alternator. And just like cars, in small boats there is not a service battery, which means while engine is not running voltage is 12v. While starting the engine, voltage can drop down to 10v. While engine is running, there is a lot of noise (or jitter) and voltage is 14.4v. My solution was to use two coils, then a group of capacitors then a boost converter (increases the voltage to 15v) then a buck converter (reduces the voltage to 12v). 🤣😂 This devides the heat dissipation, reduces the jitter and just works... But in lower power applications (like 1-2amps) buck-boost converters works very nice.
This is a bit silly because the 4g modem/router internally has buck converters, which you obviously cannot get around, so you are forced to use this roundabout way. High freq, and highly integrated GaN buck-boost would have worked for you well, but this tech is not very widely available yet, and probably more expensive than chaining two very simple converters like you have done.
Have you considered using a synchronous switching configuration rather than the diode? Perhaps that would give you a better efficiency payoff than using the coupled inductor.
using a transformer ensure 5percent increase, lossen coupled one gives anther 1percent boost, a llc typology needs pmos, or bootstrap, whichs means bad, really bad, especially in boost condition.......
I think you can build a boost converter circuit on a perfboard but you must put the components much closer together, the distance you use wouldn't work properly on any PCB type I think. All datasheets of switching power supply IC's are always hammer on that you must keep the loops as short as possible.
I have a DC to DC converter which have 3 inductors. Yeah. Its a buck boost converter but at the same time converts a single supply input into a double supply output. Its incredibly useful, but the problem is that it can output only 20w max. Is there a way to build such a circuit that can output a bigger amount of power like 200 or 400w? It can be incredibly useful to run POWERFUL audio amplifiers without transformer, just from a battery. Please, this is probably the most interesting voltage converter and in my opinion its worth giving it a shot. I used JLCPCB for the first time a few days ago and ordered some boards (layout made by me, schematic found on the internet and made better). They are 200w audio amplifiers but they require a double supply. Its propably possibile build one of those, but i cant design it unfortunately. Some online schermatics dont look so promising...
@@gianluca458 ciao Gian, ti scrivo in italiano che faccio prima. Non ho visto li schema me la teoria del potenziamento è questa: stesso schema, condensatori che portino tensioni e correnti di ripple maggiori, induttanze con valore leggermente minore e che portino più corrente, MOSFET con tensioni maggiori e Rds(on) adeguate alle nuove correnti in gioco e idem per i diodi. Se puoi mandarmi lo schema o ti servono altri consigli, io ci sono
IMPORTANT QUESTION: HELP 🥺🥺 Hi! I can't find your recent video about these boost converter that you created to produce high current output. I just want to ask if there is a commercial step-up boost converter board that can output adjustable voltage with high current from 3.7v 30Amp 18650 battery? All the boards I have are just producing 0.5 to 1 Ampere even if I use 30amp battery.. the board itself limits the output current. Can you help me, please? 🥺🥺🥺
Your definitely one of the most intelligent you tubers lol. Live your channel. When I finally get my parts replaced and back too work I’m definitely funding your channel lol. Ty for your time and research my friend.
Hello sir, I want to Make A boost Converter Which Can Handle 20V 40A @ Input side and Deliver 53V 10-15A @ Output , Can i use TL494 IC for this ? as of now i figure out the MOSFET ,Inductor and Diode for this purpose Just Confuse about Gate Driver and Voltage Feedback.. Help Me to Find Out the Best Posible Way. Thank you
@greatscottlab Do you know if aliexpress has any variable power modules that can be controlled though i2c.. I want to make a i2c controlled bench power supply. Maybe modify the Dave Jones PWM supply, using a i2c PWM servo controller and ADC feedback to make sure the output matches what you asked for.. and make a triple output supply
.. actually, you've hit upon something that us older-schoolers have Always Known - . Coil Values are Always taken "when the curcuit is Active." .. . . example; AM Radio Transmitters require 569uH but the curcuits parts list says "10uH" .. care to Explain ....
Thanks for the video, it was very interesting to see a different approach, perhaps you can help me with a problem, I want to make an 18650 12v power supply to run an emergency LED light, so do I put three 18650 in series to give me my 12 volts or do I put my 18650 batteries in parallel to give me 3.7 volts and boost that voltage to 12 volts, any suggestions for the best method? Thanks, Bob in the UK
Please create amplifier for wifi router renge ...............it can be attach any lpda, ominidirection, direction anttena for hotspot Create 14 dbi antenna amplifier plzz plzz
There is a great document from Recom that explains all the topologies. There I learned about the coupled inductors. Somebody who klicked this video is probably interested in that document.
For higher currents, a 4 switch buck-boost will always be the better solution. SEPIC (as well as inverting CUK type ) switches VIN+Vout on its switch node and carries the large du/dt EMI problem. And you switch more current than Iout. That to a much larger Hot loop which includes the SEPIC coupling capacitor. In essence, you store the complete transfer energy in the inductive components so those inductors have to be sized that way.
Hello from Georgia, USA! I really appreciated this video. I do have a question that I would like to ask. I'm adding heated seats, grips, gloves, and primary clothing layers that will run off of my bike for cold weather riding. The bike has very little extra power so I'm changing all of my lights to LED and I want to use a solid state timer for the signals rather than simply adding resistors to prevent hyperflash. Most of the heated element controllers use a resistor for the lower temperature settings. It seems to me that I could use one of these boards to control the temp and actually conserve amps by using a lower setting If my gauge showed a constant draw on my battery rather than a 2a or so charge. Am I right. I'd use the FP5-139 to get the most out of each amp put out by my charging system.
Scott I have a problem on my car sterio, i can hear the engine on my speakers, I try use a speaker to rca converter to solve this problem but nothing happens! I try every solucion that internet give to me but nothing result. I saw a video from you that you have the same problem but with a bluetooth recever and I think i need some that can handle more power (14.4v with 10 or 8 amps of current draw). Can you help me with a DIY circuit or show how i can isolate the ground of my car sterio from the rest of the car?
Do you have a link to the SEPIC converter you recommended in the video? I don't see it in any of the links you gave in the description, which did not use the IPD088N04L part.
Sorry but I was not able to find that converter anywhere. I got it a long time ago. But the XL6009 is only slightly less efficient. So I would recommend that :-)
i have a stupid question: can i use inverted typology as a non-inverted converter? you know switch the polirity of the output......anyone knows? i dont dare to ask the question in class.........for instance: use cuk as a positive power supply.
Some years ago I designed and built my own SEPIC converter, and used an off-the-shelf part for coupled inductors with one core. Before I built it, I actually did simulations of coupled vs separate inductors and it helped the ripple out a bit. Once built, it worked quite well. My board also included a Ćuk converter which is basically when you take a SEPIC and swap the placement of the second inductor and diode, resulting in a negative voltage with very similar specs. Made for a nice stable+versatile bipolar +-12V supply.
I made a boost converter using a 555ic and an irf540 mosfet. I used a sepic winding of 150uf. I could get 9v input 99v output. It was fun. I'd love to know what you think of it.
( 1:21 & 6:22 ) I have used a SEPIC voltage converter that uses a coupled inductor and it has some decent efficiency and also has some protection features which is nice. The only concern I have is the EMI it might be producing specially I used mine on an audio amplifier build and it has some weird issues "sometimes" specially on its aux mode, might have to some tests on it to confirm those thingies.
are there any difference between original buck comverter and normal buck converter xl4015. I found out on online shop that there is written one with xl4015 and another original module. Both of them look the same. Are there ny difference?
12v li bms, booster oder Downer dran und damit an Lizellen um nen kompakten Batteriespeicher zu haben den man direkt an zB. 20V Solarpanel dran hängen kann.🤔.. 👉 also plug and play mässig.. Aufladbarer Akku den man mit standardhandylader 5v oder auch 12v Netz oder am Ziganz. Laden kann oder eben auch an bis zu 20v Solar. 👉 "ich denk zu einfach" 😋
Wieder sehr Interessant da Ich selbst mit Li zellen und so weiter Meine eigenen Stromkreise hab. Aber mehr als dann eine andere Powerbank, Handy, Taschenlampen und Co. aufzuladen is net drin... Wenn das Video also Bitte nochmal in deutsch währe dann währe zumindest Mir geholfen xD, Die Thematik is genau Meine Bruchstelle Booster und Downerplatinen würden wohl dann bei Solarlader ja auch praktisch Sein.. 👉 😁 glaub Ich aber nur Theorie.
I'm thinking the Prof. Slobodan "Cuk" converter deserves a thorough review. Somewhere I have my first power supply kit I built, a SEPIC-Cuk split rail design to emulate a low power computer PSU and I'm trying to recall what specifically. Man, I forget, seems like something maybe SDR related though I forget. Neat design.
Hey GreatScott! Would it be possible for you to make an adjustable 100 watt output RF amplifier useable frequency range of 7mhz to 30mhz with the input being 5-10watts. Would love to see a video on this as i’d like to make a diy amp for my ham radio.
Damn... the comment section is moved again. As usual, great content, Scott ! Wish I could do something with this but nah, not even my profession neither my job, still watching this xD
