EEVblog #232 - Lab Power Supply Design Part 5

Dave goes through the final base schematic for his Open Hardware lab power supply design.
Schematic is here:

[OutrageHarvester]

This whole series is like watching a music composer create a full-scale opera. What a happy find! I love this YT channel and can't wait to build this PSU - thank you so much for sharing your considerable talents, Dave!

[luimackjohnson]

Brilliant! I just came across this channel recently, it maybe 12 years since you made this splendid video but thank you for sharing this video. I was a bench technical officer & also specialize in microwave radio & solar power in telecommunications in my younger days some 41 years ago (I am 63 now & retired) & was attached with our local Telcom company Post & Telecommunications then (now Telikom PNG Limited) and I must say that is a good bench power supply. Thank you again, I wish you good health & May God Bless you. Greetings from Madang, Papua New Guinea!

[SebastianScholle]

The theory is really useful. Im glad dave went all the way with his design. So much to learn here.

[madkins]

Whoa!! Finally getting around to watching this series. You switched gears and didn't take anybody with you with the changes to the design from the previous video. Appreciate the thorough discussion provided on the design. Please don't stop.

[EEVblog]

@DaemonPanda Yeah, considered that, and actually had it on an early draft with another LCD using novel mounting, but just went with a LED on the front panel instead. Free micro pins is an issue.

[fdk]

Wow, it became very complicated but I like it! It's very interesting to see how an expert would design these things.

[ixamraxi]

"Decided not to use the more expensive 10-turn potentiometers"

Head = exploded.

[SigEpBlue]

Very thorough job! I'm glad that rift between you and Microchip seems to have fully healed. ;)

I went the 'easy route' for current measurement, using (three) TI INA226 in my supply design. 16-bit ADC, I2C, on-board current, voltage, and power registers, etc.

Other than that, it is SCARY, Dave, how closely our designs' functionality are to one another. Although I suppose there's only so many ways to make a wheel.... :)

[johnconrad]

he is building a high precision instrument.  amazing.  Good job.  a good engineer sharing some of his capability and knowledge.Thanks a lot.

[nobytes]

Went from handy dandy to holy moly in less than one video.

[Kryoclasm]

Dave, I love this design! I would buy a kit when you have it finalized. Looking forward to the final videos. Keep up the great work and videos!

[EEVblog]

@billysgeo The external ADC/ADC and uCurrent doesn't actually add a huge amount to the final BOM cost, you'd be surprised how much all the other stuff adds up to be.

[TerminalJack]

Nice looking power supply. I designed and built one about 20 to 25 years ago when I was just learning electronics. I opened it up not too long ago and and was amazed that it never burned my house down! LOL. There's no fuse on the mains and no heat sink on the regulator.

I still use it but need to built another now that I'm out of the "know enough to be dangerous" phase.

[rotlerin]

Absolutely awesome Dave. As a newbie most of this goes over my head but slowly and surely some of it is beginning to stick. I've equipped my workshop with most of your suggestions from an earlier vid but I can't wait to have a go at this. Hurry with the next chapter!!!! All the best to you and yours. Hope 2012 is great for you.

[mikeselectricstuff]

..with an external supply, some reverse polarity protection might be a good idea...
Another issue is that the external mains PSU should have some weak coupling (e.g. 10-100K + 10-100nf in parallel) between its negative output and mains earth - you don't want a hard connection to avoid melting scope probe ground leads, but you also don't want the output floating at half mains, which is what you tend to get from non-earthed PSUs.

[sincerelyyours]

Just binge-watched this series and I never binge-watch anything. Dave has cleared up a ton of mysteries for me. I have a cheap SMPS 32V 5A PS with good operating specs but a terrible front panel design that I would like to replace with a more user friendly interface. Hopefully I've absorbed enough of Dave's design knowledge here to finally begin that project.

[TheCrazyInventor]

I love videos like this where you show the whole design process. The power supply looks really good too. Perhaps a bit over-engineered, but it doesn't cost a whole lot more as far as I can tell. Keep up the good work, Dave. :)

[sabamacx]

Absolutely magnificent Dave, you have outdone yourself!

[asmotaku]

I won't lie, the very initiative of doing this whole tutorial series is fantastic.
Just an incentive to push you further in your next project's making : replace all this atmel, microchip ADC, DAC bushy BOM with a single SMT32F103 . There's already a 11-channels 12bits ADC in these little buggers, along with a 2-channel 12bits DAC, and you can buy pre-propulated boards on eB..y for less than $5 with all decoupling caps and mini USB-B socket mounted, with a neat 100mil SIL fanout.
I can garantee you'll fall in love.
I even wonder why we still use 8-bits MCU nowadays... Cortex M cores are cheaper, faster, consume less (since they can sleep most of the time) and are easier to debug. Don't get me wrong : I did rely on AT and PICs back in the early 2000, but the only thing that saved them from extinction is the popularity of the Arduino, which, in my experience, is more a fad than a revolution.

[DarkInsanePyro]

I just have to say that you have designed an amazing power supply and I cannot wait for further posts on it. Every aspect is appealing. I was considering getting a bench-top power supply as a component for my lab but to work off of this design would be amazing. Can't wait for future videos.
On a side note, it was interesting that Digi-Key listed the ADC converter count but not the actual channel count. Understandably there was few 4-converter ADCs as most contain only a single converter and s/h.