Hi, it's tear down time and check out what turned up on the doorstep. Thank you very much Keysight for sending in their latest bit of Kit This is going to be really interesting. This is the Keysight e36731a I Don't know why there's numbers that they keep coming up with Anyway, how does anyone remember any of them? So this is a three far. this is three bits of Kit in one.

It's a DC power supply, electronic load, and Battery emulator all in one bit of Kit Unbelievable! Uh, price starts at about 4 700 Yankee bucks. So this is not cheap, but if you need the capability of emulating batteries and doing anything with any battery related product, this is just an amazing bit of new kit. Now you've seen me do a tear down which I'll link in up here and down below. If you haven't seen it of my Uh Keithley I do actually have an old Uh Keithley battery emulator.

It's an older design, but you know it still does the business. So this not only has and equivalent to that battery emulator in it, but also an electronic load. I've got multiple electronic loads here in the lab may as well not have them anymore because it's all in the one bitter kit. And not only is it a DC power supply, but it's actually a Precision DC power supply capable of going down to Uh one micro amp or better current resolution.

And you've actually seen that demonstrated in my uh, previous mailbag video. But we're going to tear this bit of Kit down today and see what's inside it. it. is a big beast.

It's not particularly heavy and I thought it didn't have a fan, but after uh, powering up, it does actually have a fan and there is a bit of fan noise which is kind of annoying for like a bit of Kit that's designed to like, operate for like dozens of hours. you know, hundreds of hours or whatever. Actually, log in, uh, batteries and stuff like that. So yeah, not great.

But anyway, it's got digital ports. It's got the lens, it's got the USB It has the optional uh gpib. It's got uh, external sense and this is uh, external uh binding post on the the input. Speaking of which, look at this.

this is just a Bobby Dazzler. Oh thing of beauty is a joy forever. You'll notice inside there. it's got a I don't know if you can see it, but it's got a big ball that sort of like forces the wire in there.

It's really fantastic. It is a 200, uh what? Joby So the battery emulator can do uh 200 Watts 240 Watts for the electronic uh load and the power supply is similar I Believe. Now, of course you can do all this functionality with three separate bits of kit, but it's like you've got to Cobble things together. and if you don't have a properly proper battery emulator, then well, it's a real mess.

Um, because you've got to have that a queer equivalent series resistance And your power supply. It's got to be taken into account and etc. etc. So what a battery emulator does is it basically uh, simulates the ESR of a battery because the equivalent series resistance because that basically changes um with as as the battery uh depletes itself and also changes with age as well.

So there's if you're designing a battery power product. There's a couple of ways. there's only two ways you can do it. One is to actually use the actual battery and then actually discharge it over whatever the product life.

If you've got a product that lasts for hundreds of hours on a battery, then you've got to test for hundreds of hours. Or you can use a battery emulator like this to uh, actually, as the name says, emulate the discharge characteristic. not not just the discharge characteristic, but the ESR characteristic of uh, that battery and you can do this like if you're testing over temperature, you can test aging. You can test you know, charge cycles and all sorts of stuff like that.

So if you're designing the battery power product, bit of Kit like this can be very handy. As I said, the power supply is very few power supplies on the market. I Do have one here in the lab, but they're quite rare that can actually measure very low currents. This one can go down to at least one microamp, but I saw in their data sheet.

um that if you get the data out of it, you might be able to go down to 0.1 microamp resolution as well. So you know not only for so not only can it do like a couple hundred Watts uh batteries, but it seems like it can do uh, the smaller ones as well. All right, let's take this off. I am shooting this in 4k.

So oh, there we go. We're being mooned. We've got the bottom of the top board there. Um, we've got the mains power supply under here.

There's the fan that I couldn't see. So anyway, this is. um, you might think because it's basically a power supply and an electronic load, you might think that this thing is actually a four quadrant power supply. But according to to the data sheets, it's actually only a two quadrant power supply.

So it looks like so the power supply section of this can't actually do the load sink in. So it looks like they do actually literally have three instruments. and that's what might be. You know, maybe three different boards Here They're probably going to have like one power supply board.

They're going to have an electronic load board which can be like totally separate and also uh, the basically the battery emulation. All it does is it puts a series resistance on the output of the power supply. so the power spline. This thing will have another lot of circuitry.

Maybe this board? don't know yet. Um, with an equivalent with a basically an adjustable resistor which is a mosfet or a bank of mosfets that can adjust the equivalent series resistance. or Sim emulate the equivalent series resistance of your battery. So it looks like there's no panel on the bottom.

It's just one big folded case like that. It's got a kin didn't lock on it too. Um, so yeah, it looks like we can't just get access to the bottom of those Pcbs so everything's got to come out from the top side. unfortunately.

Yeah, this could take a while. Okay, this top board here. it doesn't look like it has anything to do with the battery emulation. Uh, you can see a board to board interconnect going over to the main processor board which is on the front panel here.

and then you can see all these traces running over here. Right over that is the i o uh part of the board and then you've got your Lan interface there. so that just goes back. There's a couple of pairs there and that there's just your right USB.

So yeah, they've just got Lan and USB tracers just running all the way back. the Lan and USB chips. They'll just be uh, on that front panel board in there. Well, that's interesting.

There's a little Peg there with a hole. It's like this whole board slides forward. But then there's the board to board interconnect. Yeah, I'm pretty sure this front panel has to come off first.

Otherwise, it doesn't make much sense to do what we just saw. and this metal work here. Take that screw off. Looks like this metal work goes right under there.

So yeah. I think front panel. Then this top board slides out and up and then this metal work comes out with the mains power supply. and then we can get down into the guts of it.

Uh, pesky screws under a strip? Give it a tug. uh-huh I See it moving? There you go. She moved. So I'm gonna pull that.

Yep, there we go. Ah, we're off and we can look at that. we can access the innards and this top board. it's going to slide out of there and lift off.

Ah what a Bobby Dazzler! Well I gotta make sure I reconnect those. Oh there we go. Oh look at that little uh planner jobby. Wow.

Nice. There you have it. There's an excellent example of a Planar Transformer Basically uses little Pcbs in there with uh winding. so hence you got the multiple layers in there like that.

so it's basically just a multi-layer uh PCB in there. and they use planar Transformers to get you know, more accurate and controlled. Uh Transformers You can just control the process better than you can with like a physical mechanical you know, winding with uh, wires and whatnot. So yeah, I'm dead stead.

Anyway, we've just got a DC to DC converter here. Obviously two mosfets here Bob's your uncle, but I like that's not particularly high power I don't know, they just need a DC to DC converter. Uh, for something we've got a few is over here and I yeah, it's just an off-board uh DC to DC converter. So what is it for? Well, looks like it goes up to here and luckily those are labeled as upside down so all the electrons are going to fall out.

but uh, but it just says the P3 power supply and uh, P4 E load. So the electronic? uh load. So this is the power supply for the electronic load I guess and there's a controller on the top side there. Anyway, high-res photos available on EV blog.com and looks like A and these are inductors.

Um, so we've got some common mode chokes here by the looks of it going off to this and we don't know where that ribbon cable went off to. Well, that's a mystery at the moment so we'll find out. And as you'd imagine, the digital i o there has a fair bit of protection and drive going on to it. So yeah, that's to be expected.

but uh, apart from that yeah Ethernet USB interface, the USB just goes uh, straight over there. There you go a couple of inductors and Bobs your uncle. off she goes. So got two main boards here.

one's going to be uh, power supply I don't know which one's what but one's going to be power supply and uh, one's going to be the uh electronic load and also uh to do the battery uh emulation as well which as I said is basically just a series mosfet or a bank of series mosfets that simulates the Uh ESR output of your battery. That's basically all this is. The rest is in the Uh smarts in the software and believe me, you pay extra for the software because of course you do. And look at the interconnections here.

look at the these large gigantic solid brass and then tapped in here connectors that go to uh, the front panel and you've You know You've seen how impressive they are and obviously they've got a Uh four wire uh Kelvin connection here so that's buggering off. and then over here you've got these big bus bars screwed into here. Shake Proof washes everything else big thick ass bus bars going over to here so these are effectively uh in parallel with here. this: I Think this is the electronic load over here and they're just using this.

Basically, the electronic load is just basically going to be in parallel with the output here so they can turn it off on as required because when you have a battery emulator, you don't need that electronic load. but this is a third part of the capability that's built into this thing. you wouldn't get in your normal battery emulator product. So you know they've really tried to do an all-in-one product here.

It's fantastic. And is this down here, part of the Uh battery emulator? ESR Because you don't want, you don't need to go too high in your battery ESR There's going to be a point, where is that adequate heatsinking for it off the top of my head? I Couldn't tell you. And yeah, this makes a total sense once you look at it. This is obviously the electronic load over here.

it's going to have the largest heat sinking because it's It's a purely a linear thing for the electronic load. and as I said, it's just, uh, basically connected in parallel with the main functionality of this product. A lot of people won't use the electronic load Cable in this product, they'll just use the battery emulator and we've got the power supply which is, uh, separate. So that's the switching power supply.

that'll be a high quality, uh, main switching power supply and that could be a tracking switching regulator too. We don't know. And then, and because this is a Precision product, you're going to have a linear, uh tracking regulator on the output here. So that's why it only needs a small uh, you know, a relatively small heatsink here.

because it's tracking, it's doing uh, you know it's doing most of the efficiency in the switch in and then for your extra low noise output, you just have a tracking pre-regular and I've done that in my power supply uh design Series So that's why there's not a huge amount of heat sinking on what is a power supply which is like I think it's a couple hundred Watts isn't it? And interestingly, this is actually two levels of power supply. The output here is actually on a PCB which is at a lower level than this this one up here and I think that lower level Supply goes all the way to the back end over here we can see that the remote um out well the output the rear terminal uh Power output is is here with the sense terminals as well and that's on a lower PCB than this one up here. So they're obviously using these giant bolts here as board to board interconnects. and I've done a video on designing your own electronic load that's been very popular.

Tons of people have actually built their own and they do, uh, sell their own and so we won't go into detail on the electronic uh load here. So basically these are going to be our current sense resistors here and then our mosfets which are on here. Looks like we got three main ones like that and there's also I think another three duplicate on the other side I can see as well and another little uh something or other down there as well. But yeah, basically um, an electronic mode is nothing more than it can be.

Nothing more control as well. I a resistor and a bunch of mosfets and big Heating and Bob's your uncle of course, all the Magics in the loop, stability and stuff like that making sure it doesn't oscillate and whatnot. But yeah, apart from that, don't know what that little relays down there doing. Maybe some uh, range switching perhaps? don't know? Ah, you can actually see down in there a couple of spare.

Footprints So another couple of mosfets can actually go in there. So that might be for a higher power or different voltage models. I Think it does come in different voltage and power. uh, models.

Not sure what one I've got. No, they're not four wire sense. look at that. They're two thermistors.

They got a thermistor measuring the temperature rise on the output connectors. Wow, isn't that Jazzy There's your four wire Kelvin connection. there. It is there.

That pair is actually buggering off over there, going over the relays over here and then it looks like it's going off somewhere else. Could be some circuitry on the bottom, don't know. But um, yeah. so these two big brass solar brass blocks they're just bolted in and connected to the giant pad that's under there.

Like that, You can see that there's a giant screw in there like that. So yeah, they're measuring the temperature of each connector. Wow, that's attention to detail. Now here's something interesting.

look at this. There's a large footprint for a capacitor c27 Like, you know, a huge jobby like that. But they've actually put a little daughter board in there with two, four, six, like seven, or eight. Uh, missing one.

uh, ceramic caps? Look at that. So they've obviously changed their mind there. That is very interesting. Is it not? Hmm.

so I wonder why they did that? Maybe they have to make changes depend on different models or something. Perhaps that could be maybe the reason? uh, behind that? Yeah, don't know. And there's a relay behind that. Um, so it looks like maybe is that relay like switching in that capacitor? Bank Perhaps to like because that's not like a relay for the output and it's obviously not rated for that amount of power.

So I can only think that that's switching that capacitor load there. Perhaps Interesting, huh? Maybe for different feedback optimizations? Different Loop Stability optimizations Perhaps based on Range I Don't know. There you have it. I Was on the money for that board going all the way through like that and right through to the rear terminals over there and check out all that via stitching down there.

Enormous. But uh yeah, they're basically just one big connecting ball to connect the front, uh, to the rear connections. Nice. It's the 4K resolution glamor.

It's the 4K resolution glamor shot of the main. PCB This is what's doing all the business and there's the back side of it there. and uh, let's go through this in a bit of detail. and here's the power supply.

No surprises for finding mean, well, uh, designed and manufactured this. so there's our output over there. We've got our uh screw clamps. very nice.

Um, that looks very Schmick of course. as you would expect in this, so yeah, no workers there. This is the input side over here, Mains input side and the output side. They're all.

uh, nichecon are they? Anyway, there you go. It's got, uh, thermal cut out and uh, all sorts of goodness with that. anyway. uh, fan.

For those aficionados, it's a fan. It's an X fan, an X fan. Okay, whatever. All right, let's take a quick look at the main board.

This is where all the magic happens now. I've got the uh top side of the board here and the bottom side which I have, uh, flipped over. So that's why all the numbers are backwards so that you know things line up like these mounting holes here all line up. Okay, so it's a physical map.

Uh, so it's like you're looking through. Uh, the PCB Now I was actually a little confused at first because I assumed that you know that that PCB sits on the top like this. I assumed that uh, it was somehow connected in here. but it's it's not.

There's actually no connection from that board to the front panel. uh, terminals here as we, uh, saw these big screw terminals these are the this is the actual output. so the output is actually closest to the rear output panel. On this board here is just I I've actually checked.

These are just direct physical connections via the internal planes directly to this. So the output of the board is actually at the rear end here and then it's got to travel all the way over here to get to the front. Anyway, we've got another couple of those capacitor Bunch boards there, which is, uh, rather interesting. It shows that that's a, you know a thing across the design.

so we've got three of those, which is really interesting. So this is our output here. sorry I'm moving my head around but uh, the input actually is here like this which comes from the uh, the sweet main switching uh power supply. So we've got our input here.

We've got a 20 amp surface mount fuse there. we've got a big uh filter cap. These are all top name quality. They're even nichikon or chemical or Nippon chemicon uh capacitors so no worries whatsoever.

What we've got is four uh, fets here. and these are actually uh, these jobbies. Um, these are Ti 100 volt, N-channel Nexfit power mosfets. Very nice.

So obviously that's the push pull drive for each leg of this switch in. uh Transformer here. So yeah, so this is a big switch mode power supply here. So this would be a tracking switch mode so that you don't have to dissipate as much power down in your heatsink down here.

So yeah, very nice. And then we've got another inductor. doesn't that look Schmidt Coil craft Joby Oh, very nice. Um, and these are, uh, these heatsinked uh ones here.

they're just, uh, Diode, so a full wave Bridge rectification there, some filtering, some common mode choke and output filter cap. some extra filter in here. don't know what these two resistors here are doing. Can we see the top side? No.

can't see anything there. So I'm not sure what they're doing anyway. so that is the main output here. so this is basically the output here.

common ground of course. And then we've got some more big ass filter in here and that's basically our output and that output. Uh, then goes into the main heatsink which is down here and this is the basically the series pass element that's doing. uh, not only the uh regulation because you don't want your output being directly from the switch mode supply line.

This is going to be noisy in fact I don't know what the noise spec of this thing is. and I just checked our rippler noise Peak to Peak Seven millivolts up up to 20 megahertz though uh Rippling noise RMS are to 10 megahertz. It's less than 600 micro volts, right? So it's you know. It's pretty darn clean as you'd expect because this thing's got a 14-bit analog to digital converter to get all the resolution you need.

So this series pass element here is not only working as the regulation you know, the low noise regulation linear regulation element, but it's also working as the equivalent series resistor element. How that particular Arrangement Is there not 100? Uh, sure, But I think they're getting uh, dual use functionality out of that thing. And and you don't need a massive heatsink down here because as I said, uh, having this uh regulator here, this is a tracking um switching regulator so it minimizes the voltage drop uh across here I'm sure that's got to be a tracking jobby and all of our current sensor resistors. you notice two big Dale job is here.

These are 10 Ohms a pop. These are both in parallel. Yes, they're only one percent are because you calibrated out later. These are actually, you know, very low Tempo resistors.

You pay a fortune for all of these current sense resistors like the one in my microcurrent. For example, that's like 2.50 us for one resistor. right? for the 10 million current shunt resistor I use in there Anyway, this one's got two 10 ohms in parallel. so we've got five ohms there.

That's for one range. Then we've got another two in parallel here. I Don't know why they went with through hole. Maybe for power dissipation, uh reasons? perhaps that's got the range with the highest uh Power dissipation in there anyway? Um, they? so they're 100 milliohms each.

so that's 50 Milli Ohms. So we've got five Ohms 50 Milli Ohms. And then you've got these two big surface mount jobbies up here. These are actually uh, from what I can measure one milliohm? Uh, a pop.

So you're getting 500 if they are in parallel I haven't actually checked and are they I don't know. They've got some slots cut out here. Yeah, they seem to be in series. so I'm not sure what's uh going on there.

Anyway, they could be like lower valleys I don't they're they probably are in series. Anyway, they do have. Look at this. You can see the Uh Taps coming off there because these are our four terminal Kelvin Uh ones.

These tabs here are the uh, the two tabs which you get your Kelvin connection off and that goes into an instrumentation app up here. So there's two of those. So we've got three ranges. one there, one to do with this I'm not sure if this is a separate one I'm not sure what's doing there, but anyway, it looks like like they have three different ranges separated by uh, two orders of magnitude each.

So there's not like ten, not five Ohms. And then there's not 0.5 Ohms. It goes down to 50 Milli Ohms. So it jumps by.

Uh, two orders there, not one order and you'll notice this uh, tap in the middle here. Look at all these star uh Power connections just going off like this. these are all going over to here which I'm not sure that goes with that's just powering other stuff. Um, so I'm not sure what's what's doing there, but you'll notice some very low Precision tl071 tl074 Job is they're not doing anything precise, so they're just doing like, you know, some sort of a rough window, uh, comparison or something like that.

Then you start getting your Precision ones like your 80 86, uh 76 and there's a few of those on here. There we go. I'll go to one that's not flipped down here so you can read them. uh 86, uh 76 and that's uh, an 86.75 Why they're using those two? they're both uh, low spec um Op amps are 339 quad comparator here and then there's your instrumentation amplifier.

There's an Opa 189 I think I've done a video on that and that's reading the um, the two current sense resistors here. uh STM Fanboys Go wild. there you go. STM controlling all this.

Uh, that's a um, a Lvco4. so let's just inverter and is this a DAC I can't read that anyway I won't be surprised if that's the 14-bit analog to digital converter I'm going to put a bit bit on that. Yeah, that's an Ads 220 from TI that's a 24-bit 2K sample 4 channel low power Delta Sigma ADC with PGA V ref SPI and two Dax as well. So um, yeah, that's where all the Magic's happening.

So this is yeah. but basically it says they're only got 14-bit a converter in this, but there's a 24-bit uh converter in there and you can see like labels on the board here: PCB Design has been a bit kind. constant current uh stat and things like post regulation here and constant current uh DAC for example and then uh, constant voltage DAC and constant power DAC So it looks like they got three different Uh dacs for the different modes voltage monitoring here and there's a parallel relay here. voltage sense local or something.

there's local again, voltage sense serial relay so I'm not sure how the configurations work in there, but there's current Monitor and up here it looks like we have Hardware uh over voltage uh protection trip over current protection DAC over voltage protection DAC another current monitor over over current protection trip So this is done in Hardware not software, but it looks of it Beauty Well, you'd expect it for the price. It looks like there's another current monitor uh, resistor here, but so I'd Love to see uh, the schematic for this exactly how this is arranged. I'm not going to reverse engineer it at all, but I think yeah, what they're doing is that's the Uh ESR output that does the battery emulation. They're using that as a regulation element and also the ESR capability in there.

So yeah, they don't need a massive Uh heatsink for that. as I said. yeah, they've got a tracking switching converter over here and that's the primary side drive there and not sure what that bit there is doing. Yeah, a bunch of resistors in parallel there.

Not sure what's going on, but anyway, there you go. That's that's all the Um smarts on this thing. I won't take you through the electronic load side because it's in. There's nothing on it is a bunch of mosfets and you know, a couple of Op amps.

and maybe if it's I don't often be controlled by the same micro up here, but obviously this is handling all your local regulation. They're not using the main Uh display processor to actually, uh, you know, do any of that. So it's it's got its own local regulation. You need that for Speed and you know consistency and and just separation of your design.

Like because you don't want to be doing like this. kind of like low level uh, you know stuff for your supply in your main applications process. so that's not the job for it. it's the job of the local Uh processor here to actually do that.

So it's you know it's got to do all the you know over current, over voltage protection stuff which is all happening around here. And then it's going to be controlling the regulation of your ESR and all your different modes, your constant power mode, and your constant current modes and everything else. So it's handling all that uh, sort of jazz. So there you go.

Um, block diagram wise, it's It's fairly simplistic. You know it's all the Magics in the firmware and of course all the Precision Parts All these you know, they're really expensive Parts on here and this is this is why these things cost a pretty penny. So there you have it. That's a tear down of the new Keysight battery emulator.

It's their lower cost you series. As I said, they've got real higher end units and then like all like you know, like dozens I think they mentioned like 50 different add-ons or something for their other units. It's just nuts. Um, yeah.

but I think it uses the same. It uses the same bench few battery emulation software. So yeah, we've got the ear smaller e36371a oh God can't they have real part numbers? So yeah, if you compare those two, two to three times the price. So yeah, this is the new like runt of the litter here.

but they've got these existing ones. This one's been around uh for a while. They've got another uh like a low noise uh Source down here like a photovoltaic array simulator and a big huge uh converter solution like I uh it's just nuts. they view all.

we haven't seen them all yet and this Internet of Things battery life solution. So you know if you want to do more than this. uh like the run to the Little Can Do I'm gonna have fun playing around with this thing. it's it.

can do a ton of different stuff. You can get all these different modules and things like that to expand this solution here. It's just crazy Anyway, hope you enjoyed that tear down. Found it useful of the keysight battery emulator, the E whatever it is and anyway, thanks Keith So for sending that in! Um, let me know in the comments down below.

uh what future videos you want me to do with this thing because it's incredibly powerful. So I can do lots of battery not only battery simulation, but like battery, uh, discharge testing, and all sorts of you know, weird and wonderful things we can do with this. Um, so yeah, leave it in the comments. Catch you next time.