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EEVblog

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Күн бұрын

PART 2 is HERE: • EEVblog #222 - Lab Pow...
Dave shows you how to design a simple constant current and constant voltage lab power supply that can be either software (PIC/AVR et.al microcontroller) or traditional pot controlled.
Starting with the venerable LM317, and ending up with an LT3080 solution, and the some thought processes that go into it all.
Part 1 is the conceptual design of this Open Hardware design.

Пікірлер: 461

@dadbrad852 10 жыл бұрын

What a fantastic day and age that we live in where generous individuals like you can teach through tutorials like this. Thank you so much for taking the time to do this, especially the theory explanation, I absolutely love it. Keep doing what you are doing!

@EEVblog 10 жыл бұрын

Thanks, glad you found it useful.

@TechnocraticBushman 9 жыл бұрын

EEVblog I am an almost complete newbie and looking through LDOs to build my own power supply (like real men do). I saw your new rigol PS and I figured I can code the software for one just like it, with color display, a nifty graycode encoder and all. I came across the same part and pretty much came up with the same schematic, except for the buffers which are an awesome fix I could not figure out (thank you for the opamp explanations as well. I finally understand the t-shirt). This tutorial is by far the best I've seen, for people like me, as it explains the train of thought that went into designing this which is far more important then etching techniques or explaining how to drill holes in aluminium. I also wanted to get more then 1 amp from it so what I did, since the part is based on a comparator, I put a PNP from vcc to output and it is opened by the _IN_ pin. Now I can get it up to 10 amps with proper cooling and a huge transistor. Spice shows some 20ma through the IC for a 3 amp output so I suppose I can get it up to 15-20 amps no problem, with an even bigger PNP and more cooling and it's still dirt cheap.

@ArumesYT 4 жыл бұрын

Well, generous... He was getting paid pretty well already by KZfaq when he shared this information. Don't get me wrong, I have nothing against David or this channel, I'm learning a lot from his videos too. But you have to be aware there's not just generosity at play here.

@ProteinFromTheSea 2 жыл бұрын

@@ArumesYT youtube doesnt pay very well, especially at the sort of range of veiws that he got at the time of your comment. his time could be more lucratively spent elswhere, so although he does get compensated for this, his decision to share this knowledge is definitely partially out of generosity.

@ArumesYT 2 жыл бұрын

@@ProteinFromTheSea So I say there's not JUST generosity at play. You counter that by saying it's at least PARTIALLY out of generosity. Why counter my comment when you agree? And Dave already was a full-time vlogger a this point, so apparently the pay was enough.

@fdk7014 9 жыл бұрын

This is brilliant! You should do more of these longer "let's build something" series

@meirbns 10 жыл бұрын

I have 40 years of electrical engineering experience . Just out of curiosity I looked at your video. I must admit it is an excellent presentation. I liked very much the ingenious way you build the presentation with all the "twists" in the design. Thank you very much for the brilliant presentation.

@kunalsalvi8382 7 жыл бұрын

meirbns exactly what you did as an EE? 😃

@yasithgamage 5 жыл бұрын

you posted this in 2011 and still this is like the best video that explains how to make a power supply design ! thanks very much for this !

@evanbarnes9984 Жыл бұрын

This is exactly what I've been looking for! All these years later and it's still relevant. Thanks!

@MrCrystan 7 жыл бұрын

i really can't express how helpful and useful this tutorial series is! Thanks a million for describing in so much details, it's like a 2nd year uni stuff for someone who never did Electronics beyond college. Love it!

@EEVblog 12 жыл бұрын

@zox012 Yeah, I know. It was supposed to be one episode and I shot most of it thinking that, but when I got to editing, as is often the case, I was surprised at the amount of footage I shot. It was far too long, and kinda made sense to split up into a couple of episodes. So it should be at least 3 parts now.

@Renegade30 10 жыл бұрын

Dave, I tip my hat to you. I've been pulling my hair out trying to work out how this is done and why the adjustable voltage is so simple yet the current limiting looks so complicated, but you have really spelled it out in a very descriptive way. Thanks so much!

@EEVblog 12 жыл бұрын

@scientist375 Sure I could drop a few minutes here and there if I used a script or went and re-shoot some parts to make them tighter, but it might get 40min down to say 30min at best. You can't magically compress 40 minutes worth of material into 5 or 10 minutes and keep the same content and explanation. I could make this video 1 minute long and say here's the schematic I prepared earlier, but what's the fun in that. The next video will be 20-30 minutes of looking at datasheets and tweaking

@MarkMcDaniel 4 жыл бұрын

I personally much prefer proper, long form videos like you tend to make. It allows you to explore as in depth about the subject matter as you are so inclined. I love that, tbh.

@kurchak 2 жыл бұрын

@@MarkMcDaniel Me too. Natural talking without a script. Scripts make things feel forced and unnatural. I hate scripted videos.

@00Skyfox 9 жыл бұрын

"If you don't have specs to work from, well, it's gonna be a dog's breakfast." Where do you come up with these great expressions? I love it!

@jimle22 4 жыл бұрын

He's from down under. I have and aussie friend he says things like that all the time.

@EEVblog 12 жыл бұрын

@scientist375 And the Makezine videos are quite lacking in detailed explained content. If you like that, fine, but it's not the way I like to explain stuff. I chose to show you some of my thought processes in the design, and that takes time. You can't magically shorten it, there is only so much you can fit in 5-10 minutes.

@EEVblog 12 жыл бұрын

@mitpatterson It's orange :-> That's just the colour of various length pre-cut jumper links I have. I am using red and green for the power rails if you look on the left side.

@jeffmcclain 4 жыл бұрын

Very nice progression from simplistic to more complex implementation of the design. It would be great to see an additional session dedicated to putting a "remote sense" in place...

@googacct 12 жыл бұрын

Looking forward to the rest of the tutorial. I like how you evolved the design from using more components to a little more elegant with fewer components.

@Ray-ej3jb 5 жыл бұрын

Hi Dave I'm getting back into electronics after at least 30 yrs. I can't begin to tell you how useful and informative this and the follow up videos have been. thank you so much please please do more of this type of design videos

@FirstWizardZorander 10 жыл бұрын

You make it seem easy. Well, it's not that hard, but I feel rather motivated now. I'll just get a larger apartment so I can fit an electronics lab somewhere. Thanks, as always!

@martingannon132 3 жыл бұрын

That's why I love this channel, Dave never misses a thing!

@NathanaelNewton Жыл бұрын

This is still the first result for power supply circuit design Excellent 😁

@scottieburr 6 жыл бұрын

Only just watched this video and really enjoyed it Dave. I've always been fascinated by test equipment and power supplies especially. I've designed switched modes for a living but never got round to designing a decent bench power supply for myself. this might be the inspiration I need, off to watch part 2!!

@EEVblog 12 жыл бұрын

@joshstube Look at the LT3080 datasheet, you can parallel up devices to easily increase the current capability. It's 1A because that's all I wanted for my supply design. There are a zillion high current high voltage lab power supplies out there, this isn't going to be one of them. I may consider increasing to 2A by adding another device though. All will become clear in time.

@EEVblog 12 жыл бұрын

@fridgebulb You need to follow me on Twitter :-> I slammed it in a door jam. Why does everyone assume I hit it with a hammer?

@EEVblog 12 жыл бұрын

@sorin0306 No, it won't affect the stability, the topology used ensures that.

@pjfadriquela 7 жыл бұрын

Could you make a follow up video but with a switching power supply, buck/boost converter. Also it would be interesting to see a dual rail power supply.

@c436237 12 жыл бұрын

Brilliant. I had to watch over & over 'till I understood. I don't mind the length at all. Its good for us who are learning. Good Job Dave.

@lean04 11 жыл бұрын

you could just said: hey guys copy this schematic!, but your "ladder" explanation through all of the options from simpler to harder is brilliant. It's like university for us non engineers.. congrats!!

@anjayv8347 8 жыл бұрын

thanks to dave i finally understood how to set current with any micro controller. thank you so much dave!!!

@williammorken7484 7 жыл бұрын

I appreciate all the help you have given me on my path to engineering. You are a great teacher.

@mozportal 10 жыл бұрын

Your accent/voice is actually the main reason I'm here, and maybe enthusiasm about electronics design. Really great blog, honestly. May I request that you do a review about low-cost (0-80$) dc adjustable (0~30V) laboratory power supplies? Greetings from Turkey.

@chimera5588 5 жыл бұрын

This video is great, but the trapping is driving me nuts! Lol thank you for the amazing content, and thank you for teaching a person who is learning to solder, and build electronics on their own!

@jazzzzzCat 9 жыл бұрын

Tank you Dave! Highly educational video for a second year electrical engineering student such as I

@projectsdone3248 10 жыл бұрын

Click on the link below to a Digital power supply without a microcontroller: A Digital Power Supply Without a Microcontroller! Great video Dave!

@FooBar89 6 жыл бұрын

wow, I finally understood what that voltage inserted at the bottom via the voltage buffer does :) 22:51

@EEVblog 12 жыл бұрын

@Turkeylegs39 Have considered splitting into channels, but it just dilutes the content and the audience. I can't think of any benefits that outweigh the downsides.

@EEVblog 12 жыл бұрын

@mitpatterson Oh ok, fair enough. That's not the way I typically use breadboards for simple stuff like this. Both top strips are power, and both bottom strips are ground. I think that's less confusing than having both ground and power on the top and bottom. It better follows how you would draw the schematic. Depends on the complexity of the circuit though, more complex builds can benefit from the other approach.

@EEVblog 12 жыл бұрын

Available in my Mech store. I drew it myself.

@Genuigr 12 жыл бұрын

I first watched this video maybe 2 or 3 months ago and I had no idea what was going on because I had never done electronics before. Now I can see this video and follow it (at least). I think I have to return some more times till everything gets clear and I can say that I (will) have built my PSU and not only used some things from "the guy on youtube". Thanks Dave, I love you videos and hope you'll do them for a very long time!

@EllaBananas 7 жыл бұрын

19:00 So I've gone and made that constant voltage circuit, and immediately had the exact issues you were talking about. I'm using a single NPN power transistor instead of a Darlington pair, but other than that it is effectively the same. My problem is that, while I can handle the logic and math of these things no problem, when it comes to dealing with the more complicated parts of dealing with characteristics of different voltages and resistances and crap that is where my knowledge falls apart.

@SmithKerona 6 жыл бұрын

You need to make one node of the NPN device lossy so it doesn't oscillate. For example you could insert a small value resistor (100-200 ohms) between the base of the NPN transistor and the output of the op-amp and also add some capacitance between the emitter of the NPN transistor and ground. By doing that you are actually modifying what is call the 'poles' of the feedback system. If you are interested look up stability of feedback systems.

@jonayamaha3215 2 жыл бұрын

even i understood it omg, greetings from argentina thank you so much for the free classes.

@videobenny3 6 жыл бұрын

"It's going to be a dog's breakfast..." LOL we never hear that in Minnesota.

@ljay0778 12 жыл бұрын

For an easy to learn controller programmed in "Basic" that does have a ready to use DAC and code snippets try the "PICAXE" read the 3 manuals here. Grate video!

@emekauche7505 11 жыл бұрын

THIS IS WONDERFUL WATCHING AND LISTENING TO THE LECTURE SESSION. MY LANGUAGE IS SPOKEN HERE. THANKS.

@ELECTROMAN_MX 3 жыл бұрын

that 1989 LM317 come back to work after 33 years...

@4mb127 8 жыл бұрын

Oh man, I need more studying before I'm going to understand any of this.

@nobytes2 7 жыл бұрын

4mb127 need more doing...

@derekpride658 10 жыл бұрын

Bryan Wenzel Considering fresh alkaline batteries are around 1.65V each, that's 6.6V nominal. Most likely, an extra 0.6V shouldn't damage the device. However, you can use a diode in series to drop 0.6V, or two in series to drop 1.2V if you are afraid of damaging the device. You may want a series resistor to limit the current of the lipo so it doesn't catch fire in case of a device fault.

@danielcarroll8889 2 жыл бұрын

This video was better than most of my electrical engineering lectures I paid thousands of dollars for

@ManWithBeard1990 11 жыл бұрын

I once built a switched mode power supply. Didn't work too well. I'm still proud of it, though. Especially since it was made almost exclusively from parts recycled from the ballasts of burnt out CFLs (being careful of course not to break the glass envelopes) The only parts I had to actually buy were a pnp transistor and a zener diode of the desired voltage. It doesn't have a pcb. Just soldered wires between all the parts and insulated it with duct tape. Good fun though.

@EEVblog 12 жыл бұрын

No, it's my natural voice.

@EEVblog 12 жыл бұрын

@SajjadBro You mean actually getting a PWM signal out of a microcontroller? There are plenty of tutorials out there on how to do that.

@TediCreations 10 жыл бұрын

Thank you Mr Dave. It is a very good tutorial. I learned a lot. Now I am off to part 2.

@Yosory 5 жыл бұрын

You're breathtaking. After all these years

@Rainbow__cookie 4 жыл бұрын

I heard Keanu reeves say that lol

@t4kdungdung 12 жыл бұрын

Dave the coolest guy I ever know!! Keep sharing your knowledge Dave, thanks a lot!

@adisharr 12 жыл бұрын

My new favorite video blog - thanks for all your work on these Dave :)

@NoviceRobot 5 жыл бұрын

Every time the guy tap the white board with its pen, drink.

@sarowie 11 жыл бұрын

there are a few reason for a constant current mode: Reason one is fail safe: The current limit protects both power supply and load from over current. You could design the supply to switch of hard, but... then you get an reset button which you have to press and a small peak in current (-> start up current) triggers the protection etc. The other application is current loads. Typical examples: (Power-) Leds, motors (when the should supply constant torque), magnetic actors etc.

@alecjahn 8 жыл бұрын

Now I'll have to go back to my LM 317 DIY supply (ATX PSU based) and rebuild accordingly with the LT3080. Which means I'm going to have to learn more things. Damnit, Dave! :) Thanks for this.

@jesscast5122 8 жыл бұрын

+alecjahn If it works.....Don't "Fix" it...... (goes the saying) BTW you can accomplish this with an "Emitter-follower circuit" No Darlingtons, linear regs. etc. All you need is NPN power tabs. w a power tab the V at the emitter output will always be about .5 v Less than the base bc of the Semiconductor junction. Also remember that Transistors are CURRENT amplifiers, So.... All you need to know is the BETA of the Transistor and work w it for Current regulation........ and Last, this vblog dude has his brain scattered all over the place........

@hifatpeople 8 жыл бұрын

+Jess Cast Engineers version is: If it ain't broke, fix it!

@jesscast5122 8 жыл бұрын

hifatpeople Ummmm. I am an Engineer and I don't believe that is correct.

@hifatpeople 8 жыл бұрын

Jess Cast Just because something works, doesn't mean it can't be improved.

@jesscast5122 8 жыл бұрын

hifatpeople That's true! It can also be fucked up and wasted.

@thomaslanik7215 5 жыл бұрын

Very nice, Dave. BTW, I easily found the TI Data Sheet for this device and it has great info and application info that supports and supplements (dare I say compliments!) your friendly tutorial presentation with other benefits. Excellent! Cheers, mate.

@deltamain08 9 жыл бұрын

Nice design 2 cascade LM with variable R One for constant current while the other to get constant voltage

@harryhirsch3637 3 жыл бұрын

Really nice video, especially at 17:31!

@omsingharjit 3 жыл бұрын

4:22 i think you can use single 317 for both current and Voltage controll

@sarowie 11 жыл бұрын

filter capacitors. The remove ripples (one wanted fluctuations of the voltage) from the input and output voltages. They also serve as "energy storage" when the circuit needs for a very short amount of time more current. though due various effects (inductive, regulator speed etc.) the power supply circuit needs time before it can adapt to the higher current. In the mean time, the cap is supplying this peak current.

@Strawberrymaker 9 жыл бұрын

Stm32f1 With integrated DAC only 2 bucks. Love those!

@ausprobierendannweisstdues8686 6 жыл бұрын

Thanks very much for this circuit, this is one of most important circuits for me

@zox012 12 жыл бұрын

ah i hate it when good stuff is being presented and then "to be continued" :) really looking forward to part x

@Dileptor1 12 жыл бұрын

Thank you very much for the work your're doing for all of us. You guides are great!

@LoreKrill 12 жыл бұрын

Dave; in short fantastic. Long form? The iterative design process - setting design parameters first - then engineering to meet those goals makes the 'math' problems far more understandable. Someone else has already suggested a 'tutorial' channel which is probably more work - but I try to watch every single tutorial I can. Thanks for you efforts.

@bashardabst 12 жыл бұрын

Dave for president!

@sadeghmollaii9873 Жыл бұрын

Untill 31:11 everything is reasonable and clear indeed. But after that everything becomes Ambiguous. For example consider a situation which Iset=0 and thus comparator output which is connected to feedback pin becomes zero. So final output voltage became zero to limit current (according to 35:22). Exactly at this time we modify Vset= 3v , because we want 3v in the final output, so what will happen in this situation? Final output is zero? Or 3v? If it is zero volt, then its not working correctly. because we want 3v in the final output. If it is 3v , then corrent limiter doesnt work fine. There some sort of paradox or malfunction with this topology.

@jagank.b.614 4 жыл бұрын

This is just brilliant.. I love the your way of starting simple.. best tutorial...

@laharl2k 12 жыл бұрын

u dont need a dac inside the micro for simple proyects. just use a pwm channel and use a low pass filter, if the sink and feed currents are simetric then the curve will be linear

@321reh 12 жыл бұрын

Always A Pleasure to watch your Videos!!! Dave,, I Learn Learn Learn!!!! Thanks

@dylankirdahy9591 6 жыл бұрын

Fantastic video! Thank you, Dave

@woosix7735 2 жыл бұрын

Dave: (about circuit) Beautiful! Dave, a few minutes later: It’s hopeless! pretty dramatic

@oscarcasarroja9911 7 жыл бұрын

I love your 555 T-shirt

@tanbuntry 11 жыл бұрын

If i'm correcting myself, the output diode is to have a minimum load current. Also the diode will protect, if we accidently short the output to ground I guess.

@sarowie 11 жыл бұрын

In the first schematic he showed? Yup, the constant current pot would need to handle the full current. But think positive: It would reduce the thermal stress on both regulators.

@seamonkeys12y 7 жыл бұрын

Hopefully sometime this year I will understand this.

@keithlegg 9 жыл бұрын

best channel on youtube.

@user-xs1ej5mo1y Жыл бұрын

Dog's Breakfast comment had me laughing so hard!

@clickfix 12 жыл бұрын

Thanks you, this was one of your most interesting videos yet, taught me a lot!

@colt4547 12 жыл бұрын

Good Stuff, just built a similar supply a little while back. Thanks for sharing. I've always enjoyed your videos.

@herauthon 10 жыл бұрын

Very bright light -

@mitpatterson 12 жыл бұрын

@EEVblog I was refering to the colors preprinted on the breadboard

@sarowie 11 жыл бұрын

Some ideas: 1. Take a pot with higher current rating. 2. use a range switch and discrete power resistors (and a pot for fine adjustment)

@EEVblog 12 жыл бұрын

@Vlakpage Didn't know about that, thanks. Yeah, a bit pricey!

@Genuigr 12 жыл бұрын

If you enjoy his videos and watch them for longer than 2 days, you forget that.

@user-kx8qb2ee2m 2 жыл бұрын

man you're great. I really enjoyed this! Escpeccialy the time you took to explain the theory to us. I cant believe you re going to build it even if you know its not perfect yet xD

@laharl2k 12 жыл бұрын

why not use a buck-boost instead of linear? just a 555, 393, 385 and a couple of transistors and inductances from a scrap atx supply and a low resistance mosfet, and if you want it noise free add a lc filter it's not that hard and it's also easy to understand.

@EEVblog 12 жыл бұрын

@noob64ilive Yeah, DAC's are nicer for sure, but PWM is cheap and simple. A typical 10bit PWM in a micro is good enough for 10mV steps in a 10V supply.

@lommix-games 12 жыл бұрын

eating pizza, chilling to your videos, is there anything better for an electronic engineer ?

@myousefi4060 10 жыл бұрын

Thanks Dave Your explanation is fabulous

@ulf8468 4 жыл бұрын

@33:30 Dave is telling us that we don't need the current-buffer anymore because the input to the opamp is "high impedance". How do I know that it is high impedance?

@flash001USA 10 жыл бұрын

Very nice demonstration.

@jeffmacon9127 10 жыл бұрын

i just noticed the cali liscence plate in the back says the same as the one on the delorean from "back to the future"..

@DantalionNl 11 жыл бұрын

took my 20th minutes to find part one but i finaly found it!

@jemimakhan1092 7 жыл бұрын

in 5 years from now, I hope to design circuits like you do :)

6 жыл бұрын

if you're really serious about it, checkout cmosedu.com/videos/videos.htm for circuit design

@sklepa Жыл бұрын

And how it is going?

@StevenMcconnon 11 жыл бұрын

Dave is a genius.

@AgentDexter47 12 жыл бұрын

I am going to technical high school and I really must say that you explain much better than most of my teachers XD we are currently doing right that - internals of power regulators! I really love your vid's Now I see that I've missed whole "Lab power supply" series this is going to be a long night =D

@38911bytefree 12 жыл бұрын

This idea can be easyli expanded to some sort of basic function generator ... Also consider some sort of PC connection just to add remote control or arbitrary wave form generator. Usign PWM looks nice.