Hi or should I say hello In fact, the Micro Supply says hello yes I know it's been an incredibly long time I still get constant emails and messages from people saying hey, whatever happened to the micro Supply are you ever going to finish it? ever going to get back to it? Well, here is part whatever actually I don't really know what part of this I think there's 15 official videos, but there's actually more than that because I did two videos on designing uh, this custom LCD here I'll link them all in I'm pretty sure I done videos on like custom heatsinking and stuff like that custom keyboard keypad design. anyway I thought that I'd go back to it and revisit and show you where the micro Supply actually got to. And yes, here it is here. it is a an actual functioning Uh product and I do use it occasionally.

It is quite funky. Look at this. it's got basically customized everything. It's got a customized case.

it's got customized keypad customized LCD which I've done a video on customized uh Planner the transformer in here which I don't think I've done a video on. It's got uh, customized heatsink customized connectors as well. Believe it or not, I can do a teardown and show you this. but anyway.

um, this is not necessarily an official restarting of the micro Supply designs or a continuation. but I'll show you where I got to um and what its current status is right off the bat. No, you cannot buy this. Okay, there were only a few of these uh prototypes made and they do actually work.

Um, so you can actually see here here it is here. uh Boop there it is. Um, it's actually hooked up to a load and it's drawing at 200 milliamps here and you can see the set voltage and Set current are up the top here and then you've got the actual measured output voltage and the measured output Uh current here. It's got a nice big custom advised hello here but that can be used for all sorts of stuff and it's a pretty funky little thing.

You can actually if we want to program the current up here. uh, for example, um, if we wanted to only go to say uh, 100 milliamps like that, we could enter 100 milliamps and Boom! it drops down to 100 milliamps it into the constant current mode down there. and yeah, it's a nice little Supply it does actually work. It's got USB C input over here like this so we can power that on and poop There it is and we can jump right back in there and it automatically.

uh stored the milliamps up there and one point it did actually have a Skippy uh command interface working at one point I think but I don't think at this particular one actually is programmed with that at the moment. But anyway, it does look very cool and uh, basically this story uh behind this is that of course. uh David two and when he was a working form me was actually he was the one working on this uh project at the uh time and then when he left we did like a Handover of all the documentation and all the you know, all the design files and everything still got to folder with all the stuff. I've got a giant tub with all the uh parts and everything, all the miscellaneous parts and prototypes and the thing was, they just kind of like lost interest in it um and went on with other things like as cool as this product is I think it's very cool I do think it's actually uh, too limited and um, somewhat uh, a product of its day I would actually design it very differently.

uh, today and I'll actually take you through a quick go through of the design files of this thing. but I'll show you inside ta-da this one actually I do Oh, there's one other, but there's your problem. Well no, it's not actually a problem. there's there's one of the things right.

Believe it or not that everything is custom in this. like that connector. there banana plug in interface is a custom interface like this. It wasn't um, soldered.

this one wasn't soldered in there. uh for some reason like that. but basically yeah, we got the banana plugs. Uh Custom manufactured like this.

We've got the Heatsink. Uh, custom manufactured this. uh planar. Transformer Here that's a custom manufacturer.

There's a top-down look at it there. Uh, it's got dual uh processors. there's a secondary side one and there's also a primary side uh processor as well and you can see on the bottom. uh, there's no components.

It all was a top side load here and the case had that metal threaded inserts in it. Check that out. Bobby Dazzler Um, and it was just basically the big custom LCD on the bottom side there and this is under the heatsink. here.

we've got uh two, uh Power transistors under here and that was just the bottom side of the heatsink like that, which you know was quite a nice little uh fit to envelope design like that just to go over the top. And of course the bottom had these holes spread over like that so the airflow would actually run through and over the fins. uh, properly if this was pretty much was supposed to be the finished micro. Supply although I do remember I don't recall absolute details.

sorry I haven't gone back through and extensively looked at the documentation and stuff like that. I just switched on the camera thought I'd give you an update here but I I Do believe the final conclusion um from David was that uh, we probably should go away from the planar Transformer it wasn't as good as we thought it would. uh be in actually I can show you an oil prototype we didn't always. uh, go with this customer.

Planar Transformer Yeah, Oh I Just noticed the date code is that really the 24th week 2019? Wow, here's an older uh prototype for example and we used um, some off-the-shelf isolated uh converters because that's one of one of the things with the micro. Supply is that I wanted it to be fully isolated and with hindsight that that was probably not the best idea. It was quite nice. you know to eliminate any ground issues, but in practice most people are going to like use this with an external battery uh, pack or some you know, a power bank or they're going to hook it up to their laptop which isn't you know which is floating anyway as long as you don't plug in the mains connection.

I've done a you know a whole thing on how to not blow up your oscilloscope, how to not blow up your computer and stuff like that. So really you, you do pay a huge penalty for having the isolation if I was to do this, if I was to release an actual product, I would just do away with the isolation and also uh, we paid a price because you've got to have secondary side process isolated side processing. Not only do you have to do the USB uh Power delivery negotiation which by the way is much easier these days. they're a much easier solutions to do USB power delivery.

back then it was harder and you can check out the source code. By the way, it's been available on the githubs for whatever ever since uh David left I think I actually released the software for this. So yeah, we just ended up with like multiple processes and a really complicated USB power Delivery uh solution I believe and like it just wasn't uh God You know you wouldn't believe the amount of effort that just went into the get into the USB power delivery work in uh for example and then having processor isolation and you know, primary and secondary and stuff like that and getting the cereal over and you know it's just it's just messy I would have um if I was to release a public uh product if I was to sell it I would just ditch the isolation I don't know if you think it's important, please leave it in the comments down below. but at this stage I have no intention of actually uh, going ahead and finishing this to an actual salable product, but you never say never.

anyway. um so you can see this is our prototype 1.0 so yeah, it's got a couple of bodges I'm not sure what this battery budge here is I don't know. he was maybe experimenting with, you know, putting a DC bias in some part of the circuit or something. so that was basically uh version one and you can see that we had a different uh solution for the banana Jacks uh down here for example.

we had this little you know, right angled a board with the pin headers and uh, just used off-the-shelf stuff like that and at some point we decided it was better to actually Design This custom thing because you can actually get little folded bits of metal like this. Actually custom manufactured real, uh, cheap. It's not much NRE on it and it's You know the unit cost is, you know, not much at all in the scheme of things, but you know everything adds up just having everything custom. on this.

it really adds up. Although you know as you see, it's like it's a real sexy, vital product. If you want a real sexy final product, you know you've got to do custom stuff. So I think most of the electronics is the same.

you can see it looks very similar. The power section over here I can't actually remember details I haven't actually looked at the schematic. We'll go later and have a look so you'll be seeing it fresh as will. I After many years, but yeah, we decided to um because these were quite expensive.

um, the off-the-shelf isolated converters like this. So we went for double to get uh, twice the uh Power output if memory serves me correctly. So we thought we'd try this. uh, custom planner uh Transformer down here and I don't think it's it worked out as well as we expected it worked, but it just it just didn't give the power envelope actually uh required.

So yeah, if I was to design this again I'd just ditch all the isolation and then just have one processor instead of multiple processes. I change the USB power delivery uh thing wherever that is. um and yeah because there's much easier solutions for that these days. like single chip solutions that are pre-programmed you don't have to write anything, just pre-programmed pin pinstrap it.

What? What power level do you want and it'll do the power delivery negotiation for you you and stuff like that whereas we we had to do it all from scratch back then in like 2018. anyway that's enough waffle on the hardware but I hope you agree. It is pretty bitter kit and one thing I really like is the LCD on this. I mean it just looks absolutely like fantastic.

like you know big digits. It's got the separate programming ones up here. it's got you know, a customized Uh display down here and nice big enunciators on and you know you can just see them and it's got other enunciations so you can change you know to what hour display and stuff like that and David uh he absolutely insisted on on having Jewels so because he's a Jewels Fanboy so he absolutely insisted on having a Jules capability. so it's got that too.

I Don't know if it's programmed but uh yeah I actually I think it is. Then it's got uh, different modes down here which you can set and uh, set limits firmware 1.00 for example, uh, reset, calibration and beep and reset enable and you know all sorts of functionality like that it's got a lock function and it had uh programming modes as well. but I don't think they were actually programmed in so. but anyway, yeah, I love the LCD I.

Always thought about maybe uh, designing like or just selling the LCD so that people can use it in its own, uh, in their own projects and stuff like that. Or maybe you know, design like a little Universal board for it so you can retrofit old uh products because the LCD is. it's just I Really like the design of it and it just looks beautiful. The contrast is excellent.

Oh, it's Bobby Dazzler thing of beauty Joy forever. All right, let's take a quick look at the schematic and the PCB to see what we've got here. Uh, now this is the top level uh schematic here and this is just the overall. It links in um, other sheets here.

so I've got the LDL, we've got the pre-barker got the USB isolation, we've got the main micro part and the HMI which is the human machine interface. um and then like a handy little note here about where the binding post uh came from. and as as I mentioned, uh, they are actually a custom uh, we got them custom machined, the post machined plus we designed our own little um, the right angle connectory PCB connectory spring connector thing which I believe doesn't need to be soldered. it can just be a press fit but you know, if you, if you want, if you can, you can solder it for extra reliability like we can go into the micro for example.

and so there's all sorts of stuff. Uh look, there's options up here. digikey like I Have not looked at any of this for like over three years. Yeah, so this is the main micro and we use an Stmr 32f072 C8 T6 for those playing along at home and uh yeah.

Another one of the reasons were was uh, production of course. um you couldn't get the STM micros. they were like a lot of the parts became really hard to get for a long time I believe that was one of them. Um so yeah, we've got a I can't remember why we chose that particular STM micro.

You know they've got so many variations of it. Anyway, got some regulation here. Uh, we've got an E-squared prom that's over on its own own schematic. There it is there.

It's just that's the only thing on it. This was a thing at Altium I Didn't draw this up. by the way, this is uh David two uh doing this. but this was a thing at Altium and it was in all the examples.

And then everyone in the industry started to copy. It was like okay, you're gonna put just the one E squared prom on the one sheet on the one schematic sheet and then you treat it as a sheet and then you do the modular thing like at the top level here and then you put it there like why couldn't you just put the E squared prom there It was part of Altium's modular approach. You wouldn't have to design your own boards anymore Altium At one point I Kid, you not made the PCB tool optional extra. Oh, that didn't last long.

but the whole idea was that everything in the future would be modular and it would be. You know you wouldn't have to lay out your own board because someone is already designed an E-squared prom. Why would you have to design your own? Just drop it in and and the layout's already done for you. Why would you have to lay out your own board? Just drop it.

In all these modular and it was all supposed to be the future of PCB Design was supposed to be modular and of course it never happens. So if you see there's a lot of people in the industry, yeah, we'll just put one sheet and and Altiums to blame wasn't me even though I worked there I It's just just just don't blame me. Okay, yeah, so we've got the voltage set DAC and the Iset DAC here. So we're um, using the external like the DAC output in the Stmr 32 because it's good enough.

Like this is not a hugely Precision uh Supply the internal I can't remember. It's probably a 12-bit deck. Specs aren't great, but good enough for Australia So that goes off to the regulation part, right? So here's the USB Isolation part and and we've got uh, these are all different sheets so we can go in and have a look I'm not sure. Always it says uh, rough simulation up here swap for uh P Channel jfed if this doesn't work.

Um, so I'm not sure if this was part of the final one or whether or not he selectively left these out and this is a flyback option. so I can't remember exactly what's what's doing there. Anyway, let's go into the USB uh sheet over here. Once again, there's a few notes down here: USBC 5 volts USB BC 1.2 So yeah, you've you've got to remember this is not a production ready schematic.

This is a prototype schematic. If we went into production, it would have been. You know it would have been tidied up and you can see how on the isolation side we used another STM micro here. This is the Stm32f070 so this is what we did the USB power delivery uh stuff in I believe and it was a huge stack.

It was massive. Um because at the time as I said there were I don't think there were any like like really easy to use off-the-shelf power delivery chips available. They came like a year or two. uh later now I think there's plenty of them on the market isn't there? Um where you can just plug in the chip as I said you can strap a pin and they're designed for use in simple products.

But back then like there was I think it was like a 32k micro just to do just to hold the stack for doing the the software stack for doing the my powered USB power delivery negotiation and everything else. Um, it was provided by St but we had to massage it a lot and we had lots of issues with it and all sorts of things. If memory serves me correctly and it was, you know it, it it worked. But oh geez no I wouldn't wish it upon anyone.

it was just it was just horrible to get USB power delivery working back in what? Uh, 2018. actually we did use the RT 1716. let's have a look at that. Yeah, now it's all coming back.

Yeah, we ended up using this. Rich Tech uh job I don't I think this was in the second revised one I don't think we originally used this, but this does the hardware negotiation. um for this, but you know it's um, this is a relatively simple chip. Yeah, I think we ditched.

um the older solution I don't have to pull up the older schematic. We found this easier solution. so we actually redesigned it. I think using this: Rich Tech uh programmable USBC uh PD controller and it's just pad and I squared C interface.

That's right, so it went. It was just simpler, but we still needed that isolated side micro controller in there. so it's a much smaller device but then the main micro or that drives the LCD and the keypad and drives all the DACA power supply functionality. But you needed something when you have isolated Supply Like that you need something on the isolated side to do the USB power delivery negotiation and stuff as well as um, doing the serial comms.

because we had, we wanted to send cereal back so you can do the Skippy commands and the whole works. Yeah, so it looks like we ended up using that anyway. Like each aspect of this design could be a video. It could be a 30 minute video in its own right.

So sorry if I'm going to skip things. So we just had a simple 3.3 volt regulator there just to power the local micro here. So there's notes down here about use this Sio233 part if ESR is problematic. this limits the voltage to nine volts.

So anyway, that's the V Bus. There's our USB connector there. so we've got our USB uh, you know comms in the CC1 and CC two pins which go over to the controller interface that that rich Tech uh controller over there for doing negotiation. Um, and that's just uh, some soft uh, Power um stuff.

Then we've just got a uh, programming uh interface there and pretty much that's all she wrote on that site. Although, uh, no, we've got the uart isolation here. Here you go. So this is how we got the serial comms over.

so we just use this: uh, Sky works here. Um, 8641 a low power quad Channel digital, um isolator. It didn't need to be too quick. Um, you know it's what's it.

Oh no, there you go. High speed 150 megabits per second I don't think we needed that high. so I'm not sure why we used uh, that one. Again, the choices have been, they were documented somewhere.

You'll probably have the documentation for it. So basically, we've got our microcontroller here. We've got our USB power delivery here. Uh, we've got uh, just the USB um input here, programming header, local regulation, and isolate nation And then Bingo Here is our big isolated converter with our specific uh, planner.

This would be planar transformer and we've got a characteristic curve here. Um, and you know there's a couple of engineering notes in here changed to 82k. No difference, for example. Um, so yeah, you know David's obviously making notes in here as he was testing the thing as I said, this is not a production schematic.

So yeah, um, we used an LMR 3481 uh, switching converter here and the planar Transformer that was a custom Transformer that number would have been generated by the manufacturer I can't even remember who manufactured it off the top of my head, but we got it custom manufactured the planar Transformer we'd probably have the data sheet for that somewhere I suspect Oh, look, isn't that neat? I was just browsing through the directory here and I just found like an early um 3D um thing. We obviously didn't have the keypad in there at the time, but that was just an early concept. Cool huh? And there's another one. Check it out! This is before we had settled on the keypad uh, user interface and and we were using off-the-shelf uh case here so you can see it like end caps so that I can't remember who manufactured that case but you can get like the LCD cut out in there and it had would have had rails in there.

um to slide it in and like to slide the PCB in and it says uh six Watts up the top here. So we used actually two of those uh, six Watt isolated converters as you saw in one of those original uh prototypes there. but yeah, we we never physically made um this interface but you know we just went with keypad one in the end once again, I can't remember why this one would have been a bit smaller um form factor than what we've got. same.

LCD The LCD design was settled like very early on and we didn't really change that. It was just. you know, there were several different design iterations with user interface type stuff. When we settle it on the keypad, let us know what you prefer.

Do you think that we nailed it with the keypad version that we've got now or would you prefer something a bit simpler like this? I Kind of like the keypad one. you know you could enter the numbers but I can see the Simplicity of the up down current thing but we just wanted a bit more versatility I think and uh then once we decided on that then it pushed us into a custom case. And this is quite common in the design of products like this. It can.

you know. especially when you're your specs are flexible and things like that, you sort of, you know it. You make one chat, you decide on one thing and it sort of like pushes you. Oh we now we need a custom case.

Oh now I've got the custom case. Oh we need a custom. You know we can do a custom heatsink and or we could do this other thing and we can do this thing and you know or we can add a bit more power so we'll do our you know, our own isolated uh planar Transformer and like you know it's just yeah. it goes on and on.

You can go down the rabbit hole anyway. let us know what you think and that's just the full LC But I've shown that in the LCD design video I Have no idea what that is I don't know what that is, what the And then there's our design notes and documentation like this: I Found just you know. Found some random Uh documents in here. Uh, clearly we're analyzing the amount of flash memory required for various things.

The amount of SRAM You know the flash? like? we're going through different choices for the different Uh micros there by the looks of it. Yeah, so these were just like a selective copy and paste from the data sheet into your own design document. That's a common Uh technique just to add like so you don't have to search through. You've got it all.

Like if you take out, extract the important stuff, copy and paste them out into your own design documents and then obviously you know we'll mucking around with this. And and then there's other design, random design analysis stuff. negative Rail Solutions uh for example. um, the availability.

Like you know, risk. Uh, total risk. Uh, total cost and things like that. You know which is the lowest risk solution for generating a negative Rail and stuff like that, you know, just little design things, then just some notes on the efficiency of or the potential efficiency of various Uh switching regulator chips for example, and some compensator uh design notes for example.

if once again, yeah, I won't go through them all. but uh yeah. neat. Um, you know a lot of effort was put into, you know, various uh, selection and design processes of all the stuff that went into this.

And there's just a close-up photo of our custom Planar Transformer There you can see the multi layers in there. If you don't know what planar Transformer is, it's basically a PCB and it's a model layer PCB and these put the turns on flat on there on the multi-layer PCB and you get different thicknesses and copper. I've done a recent video on that um and yeah, you can do. There's some efficiency advantages to plan our Transformers but basically a real low profile thing.

that's one of the major advantages uh to the planner. Technique like this is you can get all those turns in a little nice smallish form factor. and before we physically built anything we would do like 3D renders like this so we could, you know, really get a feel for it and we could, you know, panned it around and everything get a real feel for you know what it was going to look like so that looks like yeah, that's our finished, that's our finished design is what we got. It looks almost identical to what we got.

Anyway, back to our Um main isolated uh switch in converter here. um and we've got a classic Rtl431 down here and then it's just a feedback opto isolator. Here, it's You know, it's pretty much straight out of the LMR 3481 data sheet. I Think you'll find and you know that's where all uh, you know, formulas and stuff come from.

Perhaps you know once again, go check out that. uh, follow along at home if you want modified set point 15.5 volts. All right. So we must have another uh tracking there it is pre-buck I mentioned that at the start, didn't I So yes, this is the tracking pre-regulator which it means that you minimize or you keep a fixed voltage drop across your output pass uh transistor so you've got a no and power dissipation.

which is why we could use a relatively small heatsink. um in there to you know, very low, quite low profile. uh. heating doesn't need much square area at all because we're only dropping at most you know, a a like two, say two volts for example, across the output transistors.

Then at one amp, you're only talking uh, two Watts for example, which you could dissipate in that heating. It's much easier. And here is the pot. Okay, here is the digital pot here and that's how we adjust it.

And yep, there we go. It's an Ad5260. Go and look that up for yourself. You'll find that's a digital pot.

Not sure how many uh, steps or whatever. Um, but yeah, that's often one of the easiest ways to do this sort of thing is to use a digital pipe. It's more expensive. Um, like the the digital Parts generally aren't that cheap, especially like an analog guard devices one down there, but it's just a nice analogy Way to do it because you're still in the analog domain here.

and it's just yeah. it's just easy. Oh yeah, there it is. The net over here is labeled 15 volts.

So that switching uh, that main isolator switching converter? a fixed 15 volt uh, output there I Think we did actually investigate actually using that as the adjustable and getting that adjustable. but it was like it was just easier to use a um, this is an AP 5313? huh? Not recommended for new design. There you go: the Ap3513. So even if we went with that, it's obsoleted already.

So 18 volt 3 amp synchronous? Uh. Buck converter. Yeah, so it's just the application circuit here and you just replace R1 here with one of those digital pots. Bob's your uncle.

You can get your tracking pre-regulator easy peasy, lemon squeezy. but I guarantee you that part would not have been not recommended for new designs which is effectively obsolete. Don't use it unless you've like got an older product and then do a last buy or something like that by all you can because we're not going to make this sucker anymore. Um, yeah, so that would that would not have been the case when we designed this.

that was only five less than five years ago. So yeah, it's gone ski. So here's where you're all here to see: I Suspect is this Ldo? What do we got here? Yeah, we've got a whole bunch of design notes I out vsense Okay So we've got two output pass transistors here. they are the same NTD 2955 Couldn't tell you why we selected that.

it might be one in in one of the design uh note uh, documents here we've got a one ohm current shunt resistor here, then just a differential amplifier I think in the previous version we tried to get away with something much simpler uh than an Opa thought like we'll say try to save like every cent on the cost and I like yeah Anyway, we we went with uh, just like a regular Op-amp Um here this is not a uh differential. um like a proper current shunt like hi say current shunt. Oh bam, it's just not bam Yeah, it's nothing special about that at all. It's just a Um 10 Meg roller rail Automotive grade op amp.

So yeah, no, we decided I guess for cost reasons. uh, not to go with a uh, like a proper like a high side differential because this is a high side. It's not in the low side. If it was low side, it'd be where's where's your ground, Where's your ground pin? Where's our ground pin? It's not there.

There must be another sheet. But yeah, it'd be on the low side. Um which? On The Ground Terminal So that would be low side current sensing. This has been.

this would be what you've what you'll call high side current sensing. So if you're after a like a differential, a proper differential amp. Uh, to do this, then you'd be looking for High Sight current sense amplifiers. But we just used an Op amp there.

No worries. Uh, does the job. So obviously this here is all part of our um of our current regulation um. circuit.

So we've got current regulation. So this is our current regulation. Uh, past transistor. And this is our voltage regulation past transistor.

And if we're not in current limit mode, of course this is just like basically a short circuit. it goes straight through and then this transistor here is the one that's limiting your output. Uh, voltage here. And once again, I could do a whole video on the design of this thing.

but I believe that looks like our final. Yeah, that looks like our final output stage here. Uh, do we? Oh yeah. Okay, no, we didn't reuse that.

That's a different Op-amp That's a Opa 2180. That was an Opa 41 72. Oh, there's the 4172 again. So I have 4172 Opa 2180.

So we're using 2180 there and there and this one there there and there. I'm not sure what's going on. Oh I end up here as well so that that's a quad jobby, but it looks, uh, no. the 72 on the end now, is that just a jewel? Whatever.

So anyway, you can knock yourself out. uh, analyzing that if you like. We've got the Uh formula there for uh, getting the output Uh current there and it's just a standard Uh configuration for the output voltage drive. Here we've got a TVs on the output.

We've got a PTC for protection. Um, not a huge amount and this is just tapping off. That'd be going over uh to the microcontroller to, you know, when you saw 12.01 volts on there, that's where it's getting from. It's just tapping it off there.

Um, and that's about all she wrote Oh and then I forgot down here. Um to know if we're in constant current or constant voltage mode Hardware wise. So the micro could tell. if you know if we're in constant voltage or constant current, there's a dedicated Um circuit there LMR three, two, one, uh, just a comparator here and it just knows which one and then um signals the micro there.

So uh, yeah, that's just power for the Op-amps And so there it is that's the Um output circuit. Once again, you can make it simpler than that. Um, once again. I Couldn't tell you the exact design decisions, but this has changed a lot over the years.

especially in my hands up. Who wants to see a video? I've got them right here. actually I've had them sit now for ages. so I'm probably going to do the video, but leave it in the comments down below because I may not get around to it.

so kick me up the backside If you want to see the whole history of every I think I've got every micro Supply prototype I've ever done. there's like half a dozen of them All through the years this project has been going on before I did the before I started the Eev log that's how long ago I can remember uh when I had the first prototype I was working at Altium at the time and uh Leo Simpson the then editor of Silicon Chip magazine. He was visiting Outium for some reason and just dropped in to say hi I don't know and chew the fat? No idea. Anyway, um, he knew that I was uh working there.

so he dropped by my cubicle I found out where my cubicle was dropped by my cubicle said Hi and um and I happen to have my original micro Supply prototype because this is before the blog I was thinking about. you know, publishing it in Silicon Chip magazine they go Hey Leo check this out and he and he really loved it. He thought it was an absolutely fantastic idea. It fitted in the Jiffy box just like the microcurrent fit in the same Jiffy bar boxes, my microcurrent and um and it had knobs and a lead and dual lead displays on it I think it was and he just loved the idea and uh yeah so but um I never got around to finish I changed the design a couple of times and I never got around to publishing it in Silicon Chip magazine.

so I don't know but he thought it was fantastic. It was desperately waiting me for me to finish it off and write the article because he loved the look of and just the idea of a USB um micro Supply there it is back in Uh 2009 that was in 2009 and then It upgraded to 2010. So thumbs up! comment down below if you want to see a video looking through all of the different um history of the uh things. so yeah, this is just a really it's just been a fun hobby project of mine.

um and it almost made it. but uh anyway, I'll tell you about that at the end. would you like to see just a quick look at the PCB here? So here's just a 3D version of that, but you send a thing in real life so it looked pretty. uh, you know it was pretty spot on actually.

Yeah, that looks pretty good doesn't it? And it's a four layer uh board obviously and you can see the layout here. it's you know, not much to it really. What can I say? Um yeah, we've got a split plane in there, obviously. So there's our component side uh, internal power supply? uh plane there just separating them internal ground planes so that we're physically, uh, separate and just bottom side there.

In fact, there's hardly any traces at all on the bottom side. It's all going over to the LCD there. Oh yeah, I forgot to show you the LCD um human machine interface? Is it human machine interface? And there we go. So there you go.

That LCD had eight, uh Commons there. and however, 31 segments and a HTR 1622. uh, LCD driver. I Think we? we? Yeah, we couldn't find the St Some SD micros of course have built-in LCD drivers, but we couldn't get it or it didn't already increase the cost too much.

and it was cheaper to get a separate chip. So I'll look that one up. So that was just a whole Tech Joby Holtex. One of you know, they make their own micros of course and they make LCD drivers and you know they're they're pretty cheap I don't know exactly, uh, the cost to that.

but yeah, um, the support of 32 set. Yeah, it supported 32 segments 1622 with eight. Uh, Commons. So we practically maxed out.

uh, that whole thing. So yeah, it was, just, uh, cheaper and more better just to get a separate LCD controller because then you weren't really constrained with uh, the St micro or your microcontroller selection, Then if you try and get it uh, built in. Sometimes you win with that, but this required a lot of segments. A lot of comments like it was, you know, quite a complex LCD on this thing.

So yeah, it was probably a no-brainer at the time for us to go to the external LCD controller. So there you have it. I hope you enjoyed that update of the micro. Supply There Yet as I said at this stage, I have no intention of actually releasing this as a finalized product.

you might get to Dave You know the uh, the the meme? just you know Shut Up And Take My Money kind of meme. I don't know. Leave it down below if you want to shut up me to shut up and uh, take my money. but I I look I I wouldn't I wouldn't go ahead with manufacturing this I think uh these days it like there are portable power supplies now.

back when I was doing this, nothing existed. There was no such thing as a USB power like a portable power supply. Now there's a few um on the market. I Still think this is like this is by far the coolest looking one.

but I think with the isolation in there I Probably like we could get the bill of materials cost down because the bill and materials cost was getting quite high on this one. I Was getting concerned that it was missing the market segment. Uh with the you know the multiplier I had to add on it and everything else I thought you know it was yeah. like would people pay yeah, like a real premium for this thing or is price more important? Once again, leave it in the comments down below.

Would you pay anything for this or would you go oh no I don't I'd only pay 50 bucks or I'd only pay 100 bucks or whatever you know. um and by adding like a whole bunch of stuff, it all starts adding up. So yeah, if I was going to go ahead with this as I said I'd probably just drop the isolation and just have a simpler USB um solution chip. Although that one we had was you know is is fairly decent, you just have to send it some I squared C uh commands and that's and Bob's your uncle I think But as I said, there's even simpler ones now which like just I think you know like an eight pin dip or something off off hand I couldn't tell you the number leave it once again, leave it down below if you know of a good one.

um where you just like pinstrap the thing they're designed for Ultra simple products that are powered from USB and you just you know all it does is negotiate like you strap the pin and say I want 20 watts or whatever or whatever the you know, whatever USB standard you want and it just negotiates the highest one up to that depending on the capability of the supplier that you actually plug into the thing and um, yeah, and then it just simply supplies that and then I just have a um, you know a there's even easier solutions for tracking pre-regulators Uh, these days and stuff like that might make it entirely switching. I Might go with a simpler output stage than you know other than the one we the audio stage that we've done did here because this is like quite a low noise. Uh, ones. you might not worry about low noise, you can make it cheaper and you can have just a switching.

uh, pre. well switching. A complete switching solution. Really, there are solutions out there.

Um, that you know you don't have to. You know you don't have to muck around as much as we've done here. so you know you can really cost optimize those ones. All those cheap power supplies out there these days.

You know they don't go to town like this, right? They're much cheaper, much simpler, and you're just, ah, who cares if it's got a bit of noise on it, you know she'll be right. Um, I'd rather have the lower cost and the Simplicity Anyway, let us know your thoughts down below about the micro. Supply I Hope you enjoyed the update. and if you did, if you enjoyed this video and you want me to make more on the continue the Micro Supply Series in whatever form, please.

Or if you want more detailed stuff on something that I've done here, let us know in the comments down below if you liked it, give it a big thumbs up. Discuss down below: Eevee Blog: Forum You know the drill. Catch you next time.