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HACKED!: Adding a Current Limit Feature to a Buck/Boost Converter

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Support me for more videos: https://www.patreon.com/GreatScott Previous video: https://youtu.be/Fj0XuYiE7HU DIY Buck/Boost Converter: https://youtu.be/ZiD_X-uo_TQ Facebook: https://www.facebook.com/greatscottlab Twitter: https://twitter.com/GreatScottLab More project information (schematic, pictures,....) on Instructables: https://www.instructables.com/id/Adding-a-Current-Limit-Feature-to-a-BuckBoost-Conv/ Parts list (incomplete, see Instructables for more): Amazon.com: 1x Buck/Boost Converter: http://amzn.to/2yh7zIW 1x LF33 Voltage Regulator: http://amzn.to/2xqkjim 1x 10nF Capacitor: http://amzn.to/2xJjZfG 1x 10µF Capacitor: http://amzn.to/2wyLbIQ 1x 0.1Ω Current shunt: http://amzn.to/2fsKACV 2x 3.3kΩ, 2x 100kΩ Resistor: http://amzn.to/2jCWbUL 1x MCP602 OpAmp: http://amzn.to/2yirlUy 1x 10kΩ Trimmer: http://amzn.to/2wyvJwu 1x UF4007 Diode: http://amzn.to/2fsKJpX 1x Voltage/Current Meter: http://amzn.to/2xddOiH Ebay: 1x Buck/Boost Converter: http://rover.ebay.com/rover/1/711-53200-19255-0/1?icep_ff3=2&pub=5575101368&toolid=10001&campid=5337582279&customid=&icep_item=263026689519&ipn=psmain&icep_vectorid=229466&kwid=902099&mtid=824&kw=lg 1x LF33 Voltage Regulator: http://rover.ebay.com/rover/1/711-53200-19255-0/1?icep_ff3=2&pub=5575101368&toolid=10001&campid=5337582279&customid=&icep_item=311572996786&ipn=psmain&icep_vectorid=229466&kwid=902099&mtid=824&kw=lg 1x 10nF Capacitor: http://rover.ebay.com/rover/1/711-53200-19255-0/1?icep_ff3=2&pub=5575101368&toolid=10001&campid=5337582279&customid=&icep_item=181982214939&ipn=psmain&icep_vectorid=229466&kwid=902099&mtid=824&kw=lg 1x 10µF Capacitor: http://rover.ebay.com/rover/1/711-53200-19255-0/1?icep_ff3=2&pub=5575101368&toolid=10001&campid=5337582279&customid=&icep_item=401206644592&ipn=psmain&icep_vectorid=229466&kwid=902099&mtid=824&kw=lg 1x 0.1Ω Current shunt: http://rover.ebay.com/rover/1/711-53200-19255-0/1?icep_ff3=2&pub=5575101368&toolid=10001&campid=5337582279&customid=&icep_item=182383981237&ipn=psmain&icep_vectorid=229466&kwid=902099&mtid=824&kw=lg 2x 3.3kΩ, 2x 100kΩ Resistor: http://rover.ebay.com/rover/1/711-53200-19255-0/1?icep_ff3=2&pub=5575101368&toolid=10001&campid=5337582279&customid=&icep_item=401036186511&ipn=psmain&icep_vectorid=229466&kwid=902099&mtid=824&kw=lg 1x MCP602 OpAmp: http://rover.ebay.com/rover/1/711-53200-19255-0/1?icep_ff3=2&pub=5575101368&toolid=10001&campid=5337582279&customid=&icep_item=181846803759&ipn=psmain&icep_vectorid=229466&kwid=902099&mtid=824&kw=lg 1x 10kΩ Trimmer: http://rover.ebay.com/rover/1/711-53200-19255-0/1?icep_ff3=2&pub=5575101368&toolid=10001&campid=5337582279&customid=&icep_item=182551169452&ipn=psmain&icep_vectorid=229466&kwid=902099&mtid=824&kw=lg 1x UF4007 Diode: http://rover.ebay.com/rover/1/711-53200-19255-0/1?icep_ff3=2&pub=5575101368&toolid=10001&campid=5337582279&customid=&icep_item=291549913009&ipn=psmain&icep_vectorid=229466&kwid=902099&mtid=824&kw=lg 1x Voltage/Current Meter: http://rover.ebay.com/rover/1/711-53200-19255-0/1?icep_ff3=2&pub=5575101368&toolid=10001&campid=5337582279&customid=&icep_item=282652383468&ipn=psmain&icep_vectorid=229466&kwid=902099&mtid=824&kw=lg Music: 2011 Lookalike by Bartlebeats Ecstatic Wave, Jens Kiilstofte https://machinimasound.com/music In this episode of HACKED! I will have a closer look at a common buck/boost converter and create a small, additional circuit that adds a current limit feature to it. With it, the buck/boost converter can be used just like a variable lab bench power supply. You want to support my videos? You can browse and buy tools&materials from my Amazon Store. This way I get a small commission: Amazon.de: http://astore.amazon.de/great043-21 Amazon.com:http://astore.amazon.com/gre09a-20 Amazon.co.uk: http://astore.amazon.co.uk/gre0b-21 Or you feel super generous and want to use this Amazon link as your Amazon home page. And do not worry, your purchases are all anonym and the prices are all the same: Amazon.de:http://www.amazon.de/?_encoding=UTF8&camp=1638&creative=19454&linkCode=ur2&site-redirect=de&tag=great043-21&linkId=ORZEQZEOVJAFURCZ Amazon.com:http://www.amazon.com/?_encoding=UTF8&camp=1789&creative=390957&linkCode=ur2&tag=gre09a-20&linkId=I5NDCEAVCD2OWM4S
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Text Comments (392)
Purti Kushwah (1 day ago)
Your videos are awesome
Aditya angara (16 days ago)
Is it possibly to modify the shunt on the LTC3780 to make it work with such low currents.
extrims70 (29 days ago)
Hope somebody has already caught electrical schenatic typo at 05:49 - differential amplifier IC1A won't work the way it shown :( Non-inverting pin.3 should be connected to junction between R2 and R3. Anyway - that's is great work, Great Scott!
abdul ghani (1 month ago)
Brother how to make smps 12v with protector?? What the parts and schematic??
omar karsly (1 month ago)
if you didn't understand anything give me Like XD
Industrial Tools Station (2 months ago)
i need to add short circuit protection to H-bridge inverter to protect the igbt's , i using 4 NGTB75N65FL2W IGBT , and the inverter is HF without transformer , do you have any Suggestion
Collector's Edition (2 months ago)
Can you show this on your diy buck boost converter
shiftew leite (3 months ago)
What about boost/buck converter with current limiting feature? those are available on the market ya know
Chee Shyong Boon (3 months ago)
something wrong with the schematic diagram which op amp IC1A pin 3 should connect in between 3.3k and 100k resistor not to GND. I guess you are trying to test your viewer :)
Lobyam Tanya (3 months ago)
Great video always
mạnh hoàng (3 months ago)
Good !
99% SELFMADE (3 months ago)
Question for a Bosst Converter! How is it possible to get a higher voltage without losing the amount of maximum Current which could flow. I mean that would give us more energy output than Input, which wouldn't make any sense. So please help me what i haven't understood yet :D
TheRealSpeedy (4 months ago)
Ich don't understand what Scott is talking about. But I love his voice. That's why I watch his videos.
Meowchin (4 months ago)
Is there a way to place the sense resistor on the high side of the load?
Navjot Singh (4 months ago)
I enjoyed it alot and you created what i wanted to have in my little electronic project but its not easy for me to build just like you did it but great video its always fun to watch your videos.
Pacero (4 months ago)
Everything within the parameters, already created by someone else.
Flying Skorpion (4 months ago)
Great project, next one should be "make a li-ion battery charger using a buck-boost converter". Interesting thing would be, how to prevent reverse flow of current.
Carlos Agorreta (4 months ago)
you are a GreatEngineer!
maxpolaris99 (4 months ago)
Great Scott! Is that a 17.1 GigaWatt Time Flux Capacitor?
gustavo baca (4 months ago)
how much current can this provide ?
GenTech Mike (4 months ago)
Does it adjust without adjusting voltage? Is it independent? Thank you.
Bibin augustin (5 months ago)
I watch all your videos And I learn from all of it But because I don't know electronics very gretely I can't make all of them But if u can create a PCB layout for this kind of circuits I could build it in ease If you could please make PCB layouts
dennis stanlee (5 months ago)
Can I add this current limit feature to a normal lab bench power supply!?
gustavo baca (4 months ago)
dennis stanlee no
Márcio Oppido (5 months ago)
For such a weak current, it is better and wiser to use an analog circuit.
Camilo Mason (6 months ago)
Hey GreatScott, I want to build this circuit. If I want a higher max output current than 1 amp, do I need to change the resistance of my shunt?
help me please
who drew this circuit in proteus?
why do you say "encharmeder" to trimmer potentiometer
MA K (6 months ago)
Can we add this project arduino and max471 module? I think it is possible. I want to ask how difficult can be and I want my project can control current and voltage on serialport.
muhammad sayed (6 months ago)
Perfect explane
odissey2 (7 months ago)
Same design of the current limiting can be found here https://youtu.be/EVL7TzCde8I, plus extra test results, showing terrible noise due to hysteretic-type control of the current. There are alternatives: https://youtu.be/wsZOzGRtZ4g
Matej Hušek (7 months ago)
Thanks!!! I Made it and with dome changes i Made my super Power supply!!!! Very good video.
Sebastian saw (7 months ago)
Hi sir, if I use a buck converter converting 24v to 5v, is it possible to get higher current from original 0.5A to higher near to 1A?
Rafi Tuito (7 months ago)
you are genius - love to see your videos!!!
osman özütemiz (7 months ago)
Voltage is dropping when u adjust current pot... Fail
Undefined Lastname (4 months ago)
osman özütemiz that's how it works idiot. Fail.
Ashwani Yadav (8 months ago)
thanks alot bro it helping us alot
Juan Sambucetti (8 months ago)
I just forgot how i was called, information overcharge...
Juan Sambucetti (8 months ago)
An i'm an engineering student, i should understand this.
Tomislav Brlek (8 months ago)
Made it, didnt work :(
Nuno Lourenço (8 months ago)
I discover your videos today! Congratulations! They are amazing! I l have a step down regulator! I need a fix current of 12v, connected to a gel battery! The problem is when the battery is full we regulator to 12v, but the problems is that the voltage of the battery will decrease and voltage of the regulator will decrease too. Do you know any step down that the output voltage can be fixed without input voltage decreases?
Muhammad Gunter (9 months ago)
So i have a question. I'm trying to learn how to use logic gates and im using a sn74ls21n duel QUAD input AND gate. How ever no matter what i do the output is always 1 despite what the inputs are. I've using the datasheet as reference.
45llamas (9 months ago)
I love your videos and how you explain it function so clearly !!
Our Creation (9 months ago)
which website you use to find datasheets of ic
richardnanis (9 months ago)
Excellent video and tipp! much appreciated! Did you also investigate the behavior of the buck/boost converter when input voltage drops below 3.8 V? I figured out that the output rises suddenly to its maximum when input voltage drops below 3.5V. This would be fatal if powered by a liion e.g. that suddenly drops below 3.5V. Then it could happen that the output of the buck-boost rises to 30 or 40 V destroying an led that might be connected to its output (or anything else). I think i got exactly the same buck-boost converter from ebay (chinese seller) - which cost me only little more than 1 euro.
MyProjectsTV (9 months ago)
I have a problem. I made a FM transmitter, but it needs 30 volts. When I use a boost converter, you can hear the switching. How can I prevent that??
alucard alucardidis (10 months ago)
Pervboard xD
Przemek Potyra (10 months ago)
Good idea is to add a bit integration to comparator circuit. Something around 10nF between output and inverting input does the trick. Much cleaner output voltage and less hissing sound from inductor.
NNNI (10 months ago)
@GreatScott!, Why use an Op-Amp?A dedicated Comparator like the LM393 is much faster.
Molasses (10 months ago)
In order to adjust the current, do you have to have some load on the output?
Praveen Elumalai (10 months ago)
If I'm right It may also influence the voltage stabilization
meanX meanX (10 months ago)
It would be interesting to see the voltage on a scope. I fear it would be more PWM style than flat.
Tech Seeker (10 months ago)
can i use opamp LM343?
Charlie F (11 months ago)
how to determine the shunt value @5:55
Sergio Ochoa (11 months ago)
Please, I have a doubt about the connection in the feedback pin of the IC. Did you connect the new feedback signal from the current limiter with the same feedback that is used for voltage measure? How does the circuit will control the output voltage if there are two signals in the same pin? Thank you!!
JC Haywire (11 months ago)
Hello again, friend. Your description needs a quick proofreading: "all anonym and the prices are all the same" Anonymous is the best word here. Cheers~
Pharoah King (1 year ago)
How can you add this feature on an diy atx psu labbench
Bertrahm (1 year ago)
Since im to cheap to buy a 'real' Variable Powersupply, would it be a good idea to use such thing as a low current 'power supply'?
DJ Slinus (10 months ago)
Bertrahm the output will be pretty noisy though so I would add a lot of filtering to the circuit
EroSs PiCcinin (1 year ago)
I hate troll comments They just... Read more
Okurka (1 year ago)
Gweat Scott!
aswin krishna (1 year ago)
Thankyou
Graham Keep (1 year ago)
Hey Scott, love the videos!!! I was just wondering, is there an easy way to see the current limit without shorting the circuit? Maybe by using an AT tiny to probe the shunt?
SEÑOR_X (1 year ago)
Hi, I have a car starter that works with 200 amps, but I want to limit the current to 15 amps to use it as a DC motor, how could I do that circuit I could use, regards.
John Conrad (1 year ago)
Look at your drawing. a "little mistake". pin 3 of the IC should be at the junction of the 3.3K and the 100K (R2 and R3) and the other end of the 100K should go to ground. anyway, this video was made on Sept 17th so by now you have already found your error. the basic idea is good but i am confused about the reason for the comparator. when u reach the current set point the comparator flips and makes the feedback input jump, thereby shutting down the circuit, etc. so it is a bang-bang circuit? what would happen if u got rid of the comparator and add the diff amp output to the feedback node via a 2 to 10K resistor? Oh well. this is your design.. Thanks for sharing. it would have been nice to see the output voltage on the scope.
hi........great work.....!!!!!! Could you please explain the same current limit feature of buck-boost converter with the help of microcontroller?
Allexandru Prroca (1 year ago)
pin positive op amp 1 goes to ground ? hmm it is suposed to be between r2 and r3 , no ?
Lagger Onesixfour (1 year ago)
Or get a buck-boost converter WITH a current limiter? Plenty of those around.
electroumit (1 year ago)
Thank you. Your voice and speech is great. I very like.
Mohammad Basil (1 year ago)
Hey GreatScott!, I am an ameture electronics hobbyist with basic tools and components (and things I don't even know about) looking forward to setting up a small electronics lab, and wanted to request a 'Lab Tour' video.. Which I am - lol.
Brian Bergh (1 year ago)
Your videos are just so cool, thanks for sharing your knowledege :P
sarmad sa (1 year ago)
😴😴😴😴😴😴😴😴😴😴😴
Daulat Ali (1 year ago)
I am use lm358 is not working,,,...
Sip Bit (1 year ago)
Is it possible to make a continuous buck boost negative converter?
Kamlesh Patil (1 year ago)
I'm planning to make solar + ac powered power bank for smarrphones. I'm ready to but even though can u make a video with it?
GameFan 2000 (1 year ago)
Can I use a 1R resistor as a shunt instead?
GameFan 2000 (1 year ago)
DIYelectronics Ok thanks. But I found out that it wastes around 10 times the power with the 1R. Just thought it would be helpfull to someone.
DIYelectronics (1 year ago)
GameFan 2000 reduce of 10 times the gain of the op-amp
J Anderson (1 year ago)
If I wanted to substitute an LM358 for the MCP602, would I need to make any changes?
EmbSysDev (1 year ago)
Is the ringing @3:01 because of the probing?
genuino 301998 (1 year ago)
Can it work as constant current source as well?
GreatScott! (1 year ago)
Yes
Darieee (1 year ago)
Amazing as always !
Simple Electronic (1 year ago)
can i use xl 6009 buck boost converter on please tell me fast
kael'thas sunstrider (1 year ago)
How can I control the current limit by an arduino? I want to dim the LED this is powering
Loundre3 (1 year ago)
Interface the Arduino with a DAC, whose output is connected to pin 6 of the MCP602 ic instead of the potenciometer. PWM with filtering will do the job aswell, just with some added noise.
TheSliderW (1 year ago)
Very interesting as always. : )
Joe Soh (1 year ago)
Hi Scott, great video as always! Mind to share where did you buy the probe shown at :2:49?
Peter Woo (1 year ago)
HIGHLIGHTTTT !
PASSTRAN eci_twi (1 year ago)
excelente amigo
Erik Kamphorst (1 year ago)
can you make a Tutorial video for EasyEDA. how it work and how can make a pcb.
GreatScott! (1 year ago)
Maybe someday
Fighter Gaming (1 year ago)
Please make a video showing how to make a multi cell lithium ion battery charger
With that being said, could you make a vid about a diy lab power supply?
GreatScott! (1 year ago)
Already did 2 videos about it.
GreatBuilder (1 year ago)
Make a tv from rgb leds i dont care what resolution it is it can even be 140p resolution but it needs to be a tv 😛
Dhruv suthar (1 year ago)
please make a video on megnatic levitation circuit very high power (to carry more weight) [email protected]
Galactic Gamers (1 year ago)
I'm only 10 and I love these vids.
lucasmonta1 (1 year ago)
Those oscilations, oh god D:
Benjamin Neuscheler (1 year ago)
Wohnst du in Deutschland und wenn ja in welchem Bundesland
zaboky (1 year ago)
Thank you!!! nice video!
DroneMan SK (1 year ago)
i have a project idea for u: try to make a 12v DC to 230v AC converter
INNOVATIVE HACKER (1 year ago)
Can you make a shocking device. Like used in shocking pen
Kaden McDonald (1 year ago)
I always get discouraged when I come to the comment section of his videos because it seems like I'm the only one that only follows like 2% of what he's talking about 😂
opera (9 months ago)
You have greater expectations than I do. I feel darn lucky that people can't find my videos.
opera (9 months ago)
You have greater expectations than I do. I feel darn lucky that people can't find my videos.
manju rani (1 year ago)
What is AKA
The Combat Engineer (1 year ago)
@Manju Rani "also known as"
Omr O (1 year ago)
I am building a bench top psu , thinking about 0-100v 0-25a using smps, what features else do you recommend?
John Conrad (1 year ago)
100V x 26 Amps is 2.5KW. good idea. very ambitious. have u made any that are about 250 Watts?
kael'thas sunstrider (1 year ago)
I can't find shunt resistors in my country :( only on really high values
Farhan Rashid (1 year ago)
Luv ur videos . Ur awesome
Farhan Rashid (1 year ago)
Please make a video on smps power supply 5v 2amps

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