Buck converter vs. linear voltage regulator - practical comparison
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- Опубликовано: 19 янв 2015
- In this video I'm comparing in practice a buck converter with LM7805 linear voltage regulator. Two driver boards from old hard drives are used as a dummy load to check efficiency and temperature of the buck converter and linear voltage regulator. I'm presenting pros and cons of both devices.
There are 2 mistakes in my calculations:
1. 5:02 - 5:08 - correct calculations should be: (12V - 5V) x 0.42A = 2.94W
2. 5:17 - 5:23 - correct calculations should be: (12V - 5V) x 0.22A = 1.54W
I double checked everything, but I should have triple checked. I'm sorry for my mistake.
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Video, edit, voice by Chris Lorkowski
Music composed and performed by Bensound - The Lounge
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Наука
Buck converters always have a little bit of output ripple. If this is undesirable, you can use a buck converter to step down to just above the dropout for your linear regulator, then use the linear regulator, which won't need to drop as much voltage, generating less heat.
wanted to know this for decades , very well explained and no stupid music , top man
YES! NO MUSIC!!!!!!!! Such a relief!!!!!
When using linear regulators ALWAYS check the datasheet for the type you are using. Many regulators will be damaged if there is a high value capacitor on the output when the power is switched off. Check the regulator datasheet for reverse bias protection.
Linear voltage regulators are a type of voltage regulator that use a linear circuit to maintain a constant voltage output. This is in contrast to switching voltage regulators, such as buck converters, which use a pulse-width modulation (PWM) circuit.
There are several key advantages of linear voltage regulators over switching voltage regulators:
- They are simpler and more reliable than switching regulators.
- They can provide a more stable output than switching regulators.
- They can be used with higher input voltages than switching regulators.
- They are less efficient than switching regulators, but this is not usually a problem for low-power applications.
In such case you have to add a feedback diode on its input and output reversed bias and you're good to go
@@drinkintea1572it's called freewheel diode🤔
We were studying power supply last week and my professor never talk about buck converter. I wish my professor had your enthusiasm to explain thinks from A to Z like you did. Excellent video.
Thank you very much Edgardo :)
I never liked theory too much and always favor practical knowledge.
Or he is smart enough to understand that someone needs to learn to walk before learn to run, or maybe he understand that efficiency is not always the design priority, for example, in RF or audio circuits powered with sockets, getting a clean power supply without the dirty noise of buck converters is the priority.
It's so hilarious to see clueless millennials learning to power led strips thinking that they have "invented electronics".
Signed: the Boomer.
Is it better to use a buck converter or linear voltage regulator in you project? ruclips.net/video/giGRrODKJSE/видео.html
I use voltage regulators to heat my house.
how?
Nickel chromium
thats not possible ..
funny though
it is very good funny way to describe that voltage regulatörs produce too much waste heat while to adjust voltage :) . the irony
This video is 5 years old and still gives good information, got everything I needed to know thanks 👍
Guys - I can't reply to some of your comments because of a RUclips bug. One of such comments is the one from Sovereign Knight. I'm getting an error message :(
Thank you for your comment and subscription Sovereigh Knight.
I am not sure, but I think it may be possible to reply by simply typing "+%user_name%". I.e., "+" is mandatory and is used to notify user through Google+ service. Although, as I have said, I am not sure, esp. considering that Google announced some time ago that they will shut down Google+.
Thanks for your advice 8thDay, but I have tried everything, including the +user_name - it didn't work too.
Wow , 8 years ago !! : D .
Awesome content. Wish I saw this a few weeks ago when I was building (using a linear regulator) a DC project. I learned through trial and error of the massive heat issue. I did end up using a buck converter.
Well-presented and well described! I needed a primer on this subject and you provided precisely what I needed to know, in a concise and easy-to-absorb manner. THANK YOU, and GOOD JOB!!
Dogmakarma Store Thanks a lot!
most useful thing i’ve seen all day, you gave me another reason to scour my spare/crap psu’s for recoverable components.
This video was the best I've seen so far for concisely describing and demonstrating the differences between the two, thanks so much for this.
Great summary. I used to build circuits when I was a kid (early 90's), reading the circuit guides from Radio Shack, but fell out of it and got more into computers & communications. I find it's still a very useful skill to have, and I'm always trying to learn more and get back into it. Channels like yours are so valuable - if we had this kind of platform when I was a kid, who knows how many cool devices and ideas we'd have by now :)
This was a very useful video; thank you! One thing I've been using linear regulators for is variable voltage but low amperage equipment, like solar chargers, etc.
Excellent Video -- informative, clear, concise script. Good camera work, good sound, well paced and edited. Very well done! Thank you!!
Really helpful. Watching your video after 5 Years and just remembered it. Good old memories
Great video! Explained in simple words.
Thank you very much! I appreciate your kind words :)
Buck converters are perfect for smaller battery powered devices.
However, if in a heavier application, then use the flat pack ic/transistor with a sufficient heat sink.
Great video.
Learned something new and got the solution of my last project in which i was facing heat problem in 7805 thanks a lot.
I just visited this video after a year , and it still has to be the best explanation yet... thanks again..
Your comment means a lot to me JOGO - thank you!
This was hands-on and educational. ☺️ Thank you for this video uploader.
use the waste heat from the linear voltage regulator to boil water for other uses.
If you wanted to boil just a single glass, it could work - who knows ;)
Yes. A tea cooker.
Hahahaha... 2 in 1 purpose. 1. For reducing voltage. 2. Boiler . (Heat generated from that linear enough to melt a plastics.
@@bhr987 if it doesnt go thermonuclear and pop before the temperature reaches plastic melting temps.
Nah you won't get enough heat for that lmao
Probably the most useful video ever suggested to me by RUclips. Thanks a lot.
You are great. You provided a very practical explanation with a very clear view of use through good camera angles and an example of best use scenarios. THANK YOU so very much.
Thank you.
I learnt something new today.
That's great! Thank you for your comment :)
When using components that require 5V only, the ripples from buck converters can be fatal. Here, the lm780X wins. It keeps the voltage very stable. Very informative video.
Thanks for this. I waz wondering why voltage regulators were used on things like arduino instead of a buck converter
No wonder my phone battery plays up on my powerbank
I knew buck converters were more efficient, but I didn't know just how much. Thank you for the explanation.
Thank you for making the regulator simple for me to understand. I always wondered how they work.
Linear regulator are not made to voltage conversion (ie, 12v to 5v), they are made to regulate voltage after a classical transformer and diode bridge rectifier. Additionally, buck converters (or conmutated power supplies) opperate at high frequencies and can cause interferences on RF or audio circuits. Each one has its pro and cons, you just need to choose the right one to your project.
Signed: The Boomer
Will it interfere with Bluetooth and wifi?
are you sure about that? because i was considering in use it in a microphone.
Computer power supplies usually have high frequency transformers to step down the voltage. At higher frequencies, transformers can be fairly small and smaller capacitors can be used for filtering.
An extraordinarily well-prepared lecture. It makes electronics look beautiful.
Clear, concise and very informative, all too often tuition videos are rendered unwatchable by totally inappropriate house music thumping out!....excellent, Thank you.
Thanks for this very helpful video. I was addicted to using linear voltage regulators on on most of my past projects (quick and dirty) but as we expand our minds and fine tune projects for efficiency and longevity buck's have a new place in my file cabinet (brain) also good call on interference potential with the buck, I never really thought about that but makes total sense for RF sensitive projects!!! this would explain why some pcb's have metal shield boxes surrounding some area's too in a way. =)
Good video. Small addition: Don't go cheap on your power supplies. Would be like going keep on the foundation of a home. When cheap power supplies fail, they can do so catastrophically.
+Kent A. Vander Velden make your own one :)
Right on, with legit components :)
+Kent A. Vander Velden Thanks for your comment and advice. You're definitely right, it's not a good idea to use cheap buck converters for important projects.
so what is a recommended buck converter?
It is not as easy as one might think, but doable :)
Thank you for that straight forward, and simple to understand comparison of the two, and a simple explanation of which situation to use which. I did not understand this before I watched this videos.
Thank you for you comment and kind words. I'm glad I could help :)
First time I know about Buck convertor.It is really efficiently work. Thank you.
Thanks a lot for the video, Clearly described :)
+Dinesh Kumar Wickramasinghe Thanks for your comment and watching :)
very educational. thanks for posting
+pebre79 Thanks for your comment :)
Great video, thank you! Also nice clever tip of using old IDE drives as dummy load!
Very clear and straightforward. Thank you!
"You now understand [...]"
Yes I do sir. Thank you very much!
Все ясно и по делу! Спасибо!
Thank you so much for clearly demonstrating the working of both.
Good video with your clear voice and without unbearable playback music.
Great Video.. Glad I watched till the end. I was considering a buck converter for a portable amplifier. I never would have known they can create interference. Good tip
wickedbadretard Thanks for your comment, I'm glad I could help.
You can find many different devices on the market: buck converters, boost converters and buck-boost converters, which is a hybrid of the former two.
Good explanation, good quality video. Thank you for this video.
Thank you for your kind words :)
Thanks for the informative video. Buck converters always sounded big, expensive and complicated for simple builds, but it's actually not that bad!
Thanks a lot for your comment. The prices went down significantly, so buck converters are not expensive at all right now.
The comperision is so cleared like water as you described. Thanks a lot .
very good video
thanks for that!
Regards from the Netherlands
R.Rob.
+R. Rob. Thanks a lot Rob! :)
Nice video, thank you! One thing though, the 7805's power consumption is (12v-5v)x.42 amp, but I get what you meant. It's a great comparison.
Thank you for your nice comment and letting me know about my mistake. I've just added annotations with corrected calculations. Sorry for my stupid mistake. I double checked everything, but I should have triple checked.
Your comment unfortunately is somewhat a rarity on RUclips. Pointing out an error in a civil professional manner. Thanks
waswestkan
Thanks a lot! I could correct the video and reupload it, but I decided to spend the time for preparing another video and let people know about my mistake. The only problem is - annotations don't work on mobile devices.
thank you my good man. Just what I was looking for. Keep doing useful videos.
This video gave me the entire knowledge which I was searching for... Thank you sir
You are so helfull, explained tons in such a short time.
take me as your new subscriber
+SOHAIL KHAN Thanks so much! I'm glad you liked this video and subscribed to my channel :)
Me too! Nice job! Keep walking.
Thank you :)
I agree he is good liked and subd
Thanks a lot :)
First, the linear voltage regulator doesn't dissipate 5.04W at .42A. You have to calculate not the PSU voltage, but the voltage that is dropped across the voltage regulator. So, (12-5)*0.42=2.94W. Same formula for the buck converter.
Second, it looks like you measured temperature of the coil of the buck converter, not the IC. Coils don't get as hot, measure the IC!
I wasn't measuring heat dissipation, it was power consumption with the load.
You are right, I measured the coil's temperature. I checked by touch and it seemed to be hotter than the IC itself. I should have measured both.
Most type of buck voltage converters i have tested and some ZVS it's the coil that gets hottest by far!
The bigger ones with power mosfet, there is a different story
Yes...coil don't get as hot as the IC
mine have 2 coil and both hotter than any ic it self, idk yours
Just the information I was looking for, thank you
Thanks for posting this. A nice clear explanation of the two options.
+Choppington Otter Thanks a lot :)
very useful video,Thank you so much
+Nick Mukbaniani
Thanks a lot! :) Sorry, I couldn't reply sooner - I was on vacation.
Excellent information. Love From India.
Thank you very much :)
Literally the exact video I needed right now.
That's great to hear/read :)
excellent information. Answered every question I had about voltage regulation and save me a TON of time and research on my project.
Thank you! I'm glad I could help you :)
Great explanation but just like to point out that you may not have incurred the failure of the VR had it been correctly setup with appropriate heat sink. This would also have improved its efficiency for your comparative data records I assume. I enjoyed the video :)
It wouldn't make any difference to efficiency. With a linear regulator, the source supplies the same amperage as the load draws from the output. With the buck regulator, the input current is much lower than what the load draws from the output. That's why it doesn't get hot. All the wattage gets passed from the source to the load. The buck converter probably dissipates less than 1/2 watt at the most.
Hello my friend,good day please can we use solar panel 12v to convert 7805 to get 5v to charge phone?
Is there a way to shield the buck converter for radio sensitive devices, for example the esp8266?
+bugs181
I guess an ESP8266 should work ok with a buck converter.
+bugs181 Yeah that should work, if not use a buck converter that provides a bit higher voltage that is needed and than a linear regulator, if you want to spend money buy the LT3080 a really really neat linear regulator, also good for building power supplies... ^^ but of course if you need a constant voltage one of the standart linear regulators would be cheaper ;-)
+Sebastian Au I've used the ld1117 as a 3v regulator for the esp8266 - it will handle the current needed. A buck converter to 5v the other side of that might be nice - but quite bulky. It is a problem with battery life on robots - always space vs weight vs battery life.
low noise versions whit inside coil
www.ti.com/tool/tida-00532
That's a good one, thanks :)
Awesome video mate exactly what i was looking to learn
Exactly what I was looking for.
thank you very much
Has anyone here tested the linearity of the buck converters vs the "linear" voltage regulator, under a variety of loads? A square-wave signal generator, for example, would be a very interesting test of a linear psu. Cheers
I haven't tested that, but I agree it could be a nice experiment. Maybe someone else has already done that. Anyone guys?
6:45 Do I see a transistor under that heatsink? ✈
Oliwer Gumowski Yes, you're a good observer :) It's a heat sink with a transistor I took from some kind of a broken device. I don't even remember what it was.
Ang good video btw it will definitly help me chose right solutions for my projects. ✈
Oliwer Gumowski Thanks Oliwer :)
Top shelve video. Many, many thanks. Everything is crystal clear, no silly comments. VERY PROFESSIONAL. Congratulation
I'm very happy you liked the video :) Thank you so much for your kind words!
I had wondered about the difference, and that makes sense , thanks for clearing that up.
is all good with buck converters but highly not reccomended when low noise is required. and that's a disadvantage against linear regulators. as a tip I would like say is good and reccomended to use linear regulator and can be efficient when difference between input and output is small. and also when circut does not drow a lot of current. lm317 or lm337 also allows us to set requied output voltage.
That's true, linear voltage regulators have advantages too. I tried to show as many advantages and disadvantages of both devices, but this subject is very broad.
Actually no.. Not all PC PSU have DC/DC step downs. The old one.. (at lest the one in our old 8086) used a a iron core transformer, with rectifier bridge and then a linear voltage regulator.
Of cause this worked pretty good because the the transformer got it down to a bit over 6V and about 13.5V for the 5 and 12V part.
The design was actually quite genius. Because they have make the transfomers in that way so the voltage of the output capacitor droped down the more load you got on it. So the power drop over the linear voltage was pretty much the same regardless of load (with in the limit).
Yea... sure, the heat sink was still pretty big and the fan was petty nosy. But the power surply actually didn´t lose that much energy.
Combining a DC/DC step down with a linear voltage regulator also works great. Having the DC/DC step down on 5.5V and the linear one on 5V makes the heat loss much more manageable.
I wasn't precise enough - most PC power supplies are switched mode supplies. Buck converters are also switched mode power supplies, but there are also other types of supplies under that same category.
Have you tried testing that theory? I mean a DC/DC step down converter and a linear voltage regulator next?
Most PSU to day... but in the 80-tys it was fairly rare.
Kind of no.. but i have seen and measured on implementations. It was in the 90-tys with a cheep nasty single phase DC/DC step down and a linear voltage regulator to keep it nice. I have not built some my self.
It might be that the DC/DC step down are that good now so its simply never needed.
Of cause i have not really built that kind of electronics since my university days. When i worked with telecom servers we always used ready to use modulus, or design pack implemented right on board.
With a bit lower volume than most electronics the time do make a better design was simply not there.
I work in IT and couldn't agree more - we always use ready to use modules and there is no time to make your own design :)
I guess that the people that designing very high quantity products, like game consoles and phones have much more time to make it with more exacting components.
The telecom servers we use to make where i worked was quite a bit larger then they would need to be
The large form factor has a lot to do with heat dissipation. Servers have to be as stable and reliable as possible, so the designers don't care about size or weight that much.
simple straight to the point - thanks very much!
Thank you so much, simple and easy to understand, 2 thumbs up!!
wow grate thank u dear i love u...
Thank you for your comment and kind words 😃
please can you tel me how can i purchaze it in pakistan?
I have no idea about Pakistani electronics market, sorry. Do you have access to eBay, Amazon, AliExpress or Banggood? You should be able to buy these items there.
Mr Engineer bro you can buy it from hall road lahore..
@@Mrengineer1 why are u gay
good idea to heat coffee cup
You would have to use a bunch of LM7805s and a bucket of electricity ;)
Very good beginners tutorial thank you. The comments are informative as well.
Very nice lesson, thanks master. Clear and concise.
+Hernan Ortiz Thanks a lot :)
Where would a resistor come in? I know a resistor can resist voltage too, but im guess they are not as efficient as buck converters?
A resistor is used to reduce current flow rather than voltage. There are some other applications too. For example, you could build a voltage divider out of resistors and get your desired voltage level, but you would have to assume constant source voltage. What's more, the efficiency of such contraptions is far from perfect.
Hi ElectonFun thanks for your reply.
So would you say a resistors best use would be to reduce small amounts of current say for a 3v LED with a power source 6v?
I have project with a power source of 12v. But most of my components are 5v to 3v. would than a buck converter be a good choice for stepping down the voltage?
Resistors are often used to reduce current drawn by LEDs to protect them from burning out. I don't know what your project is, but a buck converter should be a good idea for most projects.
codoyen - Resistance voltage dividers are used almost everywhere when noise matters. Look at some schematics.
Recent developments in LDO technology is something you should look into before touching junk, mass produced Chinese buck/boost converters.
+Shovel
dam dude... XD LoL
that is totally different..
Buck converter & LM > Regulating voltage / supplying steady voltage to circuit. (ideally didn't consume power. just passing it by. Just like non-linear component )
Resistor > Consume power. Dissipating power into heat. If you add device to the circuit after resistor, it will then divide the voltage output, which will then cannot supplying steady 5Vdc on the output side. ;-)
Its meant to BE used with a heat sink
Recently I built an analog audio effects device and was intending on powering it with a 15Vdc walwart that used a switching power supply. Turned out it created an intense whine in the signal output. I switched to a linear supply and it worked better but had hum. No matter what size cap I added, it hummed. I added a linear voltage regulator that was set about 2.5 volts lower than the supply voltage and all noise was eliminated. There's a video on using linear regulators that explained why large caps are not needed on their outputs. That gave me the answer I was needing.
Sound advise, professionally presented.
You are so informative and detailed. I was going to use a buck converter for a light on my quadcopter but you mentioned about interference and potentially saved me from a crash.
+SlNlST3R Thanks for telling me that :)
However, when it comes to quadcopters - I'm not sure if a buck converter would make any difference. These wireless controllers are quite resistant to interference. A couple of practical experiments should clear things a bit.
Very helpful information, thanks for the video!
This was awesome
You just got a subscriber
I’m not an engineer, I just like having a decent grasp on the concepts involved
I like seeing these things as, what they do or what they are used for
Like...:imagine you’d never seen a hammer before
A hammer is a tool
A circuit is a tool
Most people explain circuits with the same frame of reference as explaining a hammer like this:
“This is a kinetic energy leverage amplification device, we can calculate how much kinetic energy transfer we can expect by calculating the mass, multiplying for acceleration, then reducing wind speed and ambient air temperature and then multiplying that by the surface area of the striking surface and then dividing that by the impact surface”
And yes....this is a pretty good explanation, but it’s way too much specific information
I loved this explanation
Hi...these are 2 voltage regulators!
There’s a cheap one and an expensive one
Voltage regulators take a bunch of volts and turn it into a set voltage
The cheap ones are cheap, but, they can get real hot and explode
The expensive ones don’t explode, but you could buy 10 of the cheap ones for the price of one expensive one
Also....the expensive one can fuck with radio signals....
So....if you gotta lot of volts and want to turn it into a useable stable voltage
You can use one of these 2 thingies
But one explodes when it gets too hot, and the other fucks with radios....so keep that in mind
Very interesting and clear video. Thank You!
Very good video.solved a lot of questions for me.thank you.
Very handy and well explained. Great comparison. Cheers
Thank you so much! Cheers :)
Excellent summary and explanation.
Thank you very much :)
In a situation where one needs both 12 volts to power LEDs or a relay, but also needs 5v for CMOS logic, do you think an LM7805 would be appropriate since it wouldn't heat up very much since the CMOS chips don't consume much power?
Thanks for your explanation! It was very useful!
THANKS!, FOR THIS VERY INTERESTING TUTORIAL VIDEO!!!
Thx for your super easy to understand video. Even I got it, and u got a new subscriber.
Thank you for your kind words and subscribing :) Sorry for replying so late...
Muito bem demonstrado. Minha questão era sobre temperatura. Obrigado.
Thank you for the Practical Video 🙏
thank you, this video helped me a lot to know the differences.
Excellent, informative video. Thank you very much.
I also did the same comparison and found the same problem with linear voltage regulator as it turns too hot to handle. Now i have an actual mobile charger inside my motorcycle compartment using a buck converter. It's so convenient as i can repeatedly charge my phone anytime, anywhere where there is no AC electrical outlet and I can do this even when not not using my motorcycle. It really draws less current than the linear one therefor less heating. I am using LM2576, by the way, but i'm not using heatsink ofr that matter. This video is a confirmation that I'm doing it right. Thank you for this video.
Thanks a lot for your comment! You are doing it right - a phone won't spot the difference between the "noisy" buck converter and "clean output" linear voltage regulator. The buck converter will definitely produce less heat and draw much less current.
ElectronFun.com By the way sir 18 years ago, i powered a two way CB radio with conventional power supply using step down transformer because back then i really don't know there are different ways to power different devices. All I know is that if i have a step down transformer, a full wave bridge type rectifier diode and a filter capacitor that's it i have a power supply. I really didn't know about buck converters until just two months ago.
Your video helps a lot sir... Thank you
great job explaining and showing, thanks
james milewski Thanks a lot, I'm glad you like the video :)
Very good explanation thanks!
Thanks for very clear video. Great help in understanding power supplies
Thanks a lot Michael :)
Thank you for a good presentation. Well done and very usefull