I bought this one as I wanted a mini suitcase with all necessary tools for an electrical engineer.. I have to say, I didn't look much info about it and I just trusted my gut feeling when buying this, and I was very very impressed by it, especially for the price! Now I have a suitcase with this mini DPXXX PSU, the ATMega328 based transistor+component tester+frequency generator(pwm) thingy, DSO138 based mini digital oscilloscope (for low freq simple stuff), a "no-name" Logic 16 logic analyzer + rasperry pi zero with screen to run it on (+mini keyboard,mouse), Yihua adjustable temperature soldering iron (amazing), small ESD mat, glue gun, couple of multimeters.. and many many other stuff.. all that inside a small suitcase and I easily spent less than 100€ (with shipments) for all those stuff, haha! Thank you China for letting us poor electrical engineers to have our gadgets! :D
yeah I got mine as a portable and small power supply unit as well, it worked like a charm was worth every cent of the 30 bucks I paid for the 5A buck-boost version.
Make a quick video on your cell & post it. I am working on similar with a ridid tool organizer as the frame, dso150 kit, yaogong rework soldering iron/heat gun & would love some ideas on how to organize it😉
Yeaaahh... very helpful video, these little buck modules are super neat and super handy, thaaanks for spending time characterising it, this will help a lot of people out there!!
I really like how Dave covers the entire test equipment range, from "Don't Waste Your Money" to Unobtanium. For a useful instrument at the low end, Dave's highest praise tends to be something like "Not a Complete Waste of Money". Hearing Dave glow about $20-$50 power supply modules induces blurry double-vision with Rod Serling talking in the background over the Twilight Zone theme. Which means the world's supply of these modules is about to vanish...
Thanks for this detailed test of the module. As I and others pointed out in your previous video, you can adjust the voltage and current more quickly, while in the voltage/current adjustment mode, you can press the rotary encoder button, which will move the cursor to 0.1, 1.0 or 10v per turn. It's of course also mentoined in the manual.
I was very happy to discover that when setting the voltage and current on the main page of the DPS3003's user interface you can push the pot button and select different digits in front of or behind the decimal point to speed up the value selection you want.
Julian Gomez Dejate de joder q a Dave se le entiende perfecto el acento australiano. Mejor aprende ingles asi no necesitas subtitulos y si estas aburrido haces los subtitulos vos.
the buck-boost model works like a charm too, doesnt really even get hot enough for the fan to go on, even when pulling several amps at lowish voltages. and best thing is it works off of almost any dc power supply so its super portable as well.
Very helpful, I am thinking of purchasing 2 of these and connecting to center taped transformer with bridge rectifier to obtain negative and positive output supply. I also like the out On/Off. Can see the importance of output filtering. Great video love your all encompassing explanation - thanks
It may be that my glasses needed cleaning, but this video looks extra crispy and contrasty to me... Great content and very interesting little module. I was just researching the viability of making a quick and dirty PSU with a boost/buck converter and a LCD multimeter. This seems more compact and with many more functions!
Interestingly I managed to order a DPS3003 for AU$18.98 delivered, shortly after Dave's first video. But I now see the same listing has been bumped up to AU$28.80. These ebay sellers must love Dave!
Hi Dave Did you subtract the base power from the input power? If not then this makes them look very bad in terms of conversion at low output power (although the overall efficiency calculation would still of course be correct).
filter combined with inductor and small tantalum capacitors should smoth the output perfectly. this kind of filtering to get rid of ripple and noise is commonly use in pc power supplies and does decent job! ;) I waiting for my DPS5015. great job Dave, thanks for your efforts to characterize this nice kit ;)
Great 3 minute Video! (I think the right arrow key was invented for Dave's videos!). I also see by the comments that many viewers need a basic refresher on "reverse engineering" LC filters. Actually, no need to "reverse engineer" anything since the Regulator IC's Data Sheets and APP notes have it all!
To set the voltage press V turn the knob to change value press in on the knob to select the decimal place the same setup is used for the current. MI and M2 are used to save settings and recall settings. You can also save and recall more settings if you use the set button.
Thanks Dave I've been looking for a module like this so your video helped me make my mind up as to which one to buy. Just ordered one from ebay thanks again
Better than my Philips Rack PSU. Hasn't been calibrated since 1990... The output is very unstable. And it weighs a ton. It was a freebie, I'll fix it someday soon.
Dave, If you push the encoder while changing voltage or current on the home screen, the resolution will switch from 1mv increments up the scall with every push.
A great voltage supply for these units are old stereo receivers. For less than $20 here in the US you can get a unit from Goodwill or Salvation Army. You'll get a big transformer usually with multiple taps, and a bridge rectifier, and a big input smoothing cap for dirt cheap.
Thanks for doing this Dave. Saw these a while back and wondered if they were any good. I'd say they are a great value for the budget limited lab like mine.
If you are in the current/voltage set mode on the main graphis screen and press in the rotary encoder knob you change the cursor position so you don't have to only adjust the 10mv range, or 1ma range.
yzxstudio monitors also have bt options. Also check out powerz king meter, that one is around $50 but even more options like micro oscilloscpe function.
I ordered two DPS5005 just because of your first video and i also have two seperate 48V/4A Mains powered SMPS in order to build up a two independent outputs power supply for OpAmps or alike... Anyway, the heatsink will get heated up the most when i run the module with a rather low output voltage but high current. I hooked up my two 4Ohm/1kW dummy loads in parallel, set the maxinum current at 3.8Amps and let it run...i also had a temperature meter on the heatsink and it settled at about 50degree C with the module sitting on my bench....so if you put it in a housing it may is a good idea to have a (temp controlled)fan inside or it might overheat.... Otherwhise i have no problems found, jet. No short circuit issues, or suddenly disconnect the DUT while running at full ouput current...nor a big Cap and output switched on/off/an...the same goes for a one Henry/5Amp inductor (EI-130 core) The only thing i did not test was feeding in a reversed voltage from another power supply...as this is not a four quadrant Power Supply, i don´t know if it gonna survive...but running with the usual load conditions it does the job quite well, regarding the money i spent on them...:)
I Ordered 50V 5A and LED SMPS 48V 150W, 2 weeks ago, stil waiting to arrive. I also planned to put filters (common mode inductors and caps on both sides), filters will go between SMPS - converter (higher cap values, ceramic and elco) and converter - load (low cap values, ceramic).
Hi Dave, once you are in amps or volts push the encoder wheel to cycle across digits you want to change. I use 2 DPS5015 and it's super easy and fast to set it.
Maybe the low efficiency comes from the schottky diode used to do the freewheeling. At low output current and voltage the mosfet is off most of the time so it's the voltage drop of the diode that creates losses. They could have improved that with a synchronous design using a second mosfet instead of that diode.
What Dusan said. What could be a desired filter? Measure frequency response/step response... do some actual engineering. Efficiency measurements and such in this video are a great start :)
Noise. From experience, what applications would the noise of this device be an issue. What hobby related apps would one run into problems. For example are esp8266's, or the range of Arduino products or an old 1981 Galaga PCB on the repair bench susceptible to noise. How would you determine if you are close to the edge. TheSignalPath offered a solution to reduce noise but when would it be necessary in general hobby apps.
I've recently used the big brother of this module (DPS5015 50V 15A, 35$ on Ali) and a power supply pulled from a Cisco switch (Cisco DS-CAC-845W, going for ~20$ on ebay and doing 52V at 17A) to build myself a benchtop lab power supply that finally has some Oomph to it.. and I'm really liking it. Just needed a few more µF on the output side.. it's a little bit underequipped if you go into the double-digit amps.
Did you take apart the Cisco switch and use your own enclosure? I'm thinking of getting the 3005 or the 5015 but I don't want the PSU to take up so much space.
The mentioned Cisco PSU is a modular unit that has outputs through a big Molex-type connector. For the complete project I used an old external SCSI drive box where the PSU module fit just in, after minimal dremeling.
@EEVblog The manufacturer is Hangzhou Ruideng and there is a modified firmware available called OpenDSP created by Johan Kanflo so you can optimize it for your needs.
Here are the different PC softwares for it and also the documentation of the communications protocols (in chinese, but google translate handles them fine): www.mediafire.com/folder/3iogirsx1s0vp/DPS_communication_upper_computer
Interesting that the 1.5V output loses so much power. I wonder if it's related to the fact that in the previous video you said the chip they're using isn't really designed for down to 0V output. Perhaps some odd behavior it does at low output voltages, regardless of input
btw, you don't really need 4 meters. You can also use two meters with break-before-make switches in a clever circuit. Also, a lot of times the graphs are with log scales
Another awesome video would be to use a step-up converter like the AT30 or XL6009 module to power one of these at maximum voltage from 5-12V. Even more, these step-up converters can be probably bootstrapped to be isolated with just a coupling inductor, a capacitor and a schottky diode.
I fully intend to; gonna stick a switched and fused IEC C14 on the back and hook that up to a laptop power brick internally, as well as the obligatory cooling fan. Not sure what old chassis I'll re-purpose for this. Perhaps an old PC PSU...
Could you do a video on filtering the output for people doing audio or radio work with their bench supplies? I know some audiophiles who insist only linear power supplies can provide pure DC. I also know that's bs.
Dave were there any Load Line Regulation measurements taken to quantitative how well the output held up under various output currents? Those figures along with output noise used to be some of the first figures I used to use in evaluating power supplies.
I had the same question. A quick Google search suggests a lot of math is involved but I have a feeling there's a rule-of-thumb like "toss a 0.1 µF cap across the terminals."
theres is probably way more then 0.1uF on the output internally .... it also matters what kind of cap you are using and its ESR, a electrolytic cap is hardly going to filter out the hf switching noise at all.
Michael Eckl off the top of my head, I'd use a bunch of 1uf ceramic monoblocs (bypass caps) in parallel. (The issue here is noise, not ripple.) If I was still seeing noise under max load, add a few 47-100uf low-ESR electros or tanties.
Possibly it would be best to have capacitors, followed by inductors (or a common-mode inductor), and then a bit more capacitance. You see this kind of arrangement in fancy power supplies on their AC input to stop noise getting on the power lines.
The thing I don't like about these is they are DC/DC. I would like to see one that comes with a bridge rectifier, so you can couple it to a transformer. That way you can plug it in like a true bench supply.
Thanks Dave! I'm considering buying one. Maybe characterise the Buck-Boost one? If it does well, it is a no brainer for me. I have a spare PC PSU, laptop psu, and a few transformators, so getting some DC input wouldn't be hard. 7:12 VOOOOOOOOOOM!
There's lots of sellers for these PSUs and, yeah, some sure will change the prices. That's why it can be a bad idea to buy a product by clicking a link under a video or in a forum. But checking the orders on Aliexpress for the DPS5005, Dave already increased the sales 10-fold with the first video a few days ago. They sold less than one a day before that, but there've been around 60 orders during the last 6 days since oct.5th. Do you have the price from a week ago? Because if they react to the increased demand, they sure will have done that already.
I don't think you lot can make a dent in China's manufacturing capability at this point. Seriously, they can mobilize thousands of people putting those things together 24/7 overnight if the sales are there. Efficicency is easy when you don't have unions or overtime regulations.
Exactly what I was thinking. It would have been quite interesting to see where the 3.3v curve was positioned between the fairly nice 5v curve and the significant less efficient 1.5v output. I'm guessing it may be a lot closer to the 5v curve than the 1.5v curve.
You put in the time for this one, really interesting. What I’m interested in is the accuracy of the voltage under load - does it dip as the amps go up?
If you used a lower input voltage (for ex 5V), would the efficiency of the 1.5V output improve? I.e. if you want better efficiency for the lower output voltage ranges, is the solution to decrease the input voltage?
I wonder how the 1.5V curve would be if the input was something like 5V. Buck converters aren't that good for lowering too much like you tested (Vout = 10% Vin).
please dave , a reverse enginnering of this module will help all the guys who have a faulty unit (like me) and will protect others when their module fails.
So.. Next how to clean output. Without awfull shortcircuit current spike. And howto use this charging without diode and voltage drop. This is not protected if voltage is more that device output.
In fact dave got some poor videos too, but that is not the case, there is only one good solution if you want lab power supply with low level of noise and that is linear regulated supply.
I was hoping that 1.5 V would have lower power consumption, but that saving is turned into heat. So the device cant scale down its power? Is this about the design and the nature of electricity. Could you design it so the input voltage (force) is decreased, but then then it still needs a different circuit for max efficiency I suppose?
Would have been useful to measure the temperature of the heatsink at the same time - at least at the extremes? Also, spend 5 minutes detailing exactly what you can do to smooth out the output - adding capacitors etc. Whilst this is second nature to yourself and all experienced hobbyists it won't be to newbies (the type of person likely to be most interested in aquiring a cheap bench PSU). Anyway, anither great vid so thumbs up from me :-)
for our DC-DC power supply, we can design it better and add more function, you just add some simple AC-DC power supply, that's ok. if you find AC-DC power supply directly with same function, it will be more expensive , and many people want to do a DIY power supply . different people have difference needs
I was under the impression that the power loss that increases at lower voltages would be a characteristic of the Linear Regs, with the switching ones not burning that power since its switching.
But every time the output switch changes state, the gate of the output MOSFET needs to be charged or discharged, and temporarily the MOSFET is operated in a linear region for a very short time until the gate reaches the new control voltage. Because this happens at fixed frequency, this consumption is nearly independent of output voltage but you can assume it to be close to constant, which means nominal efficiency at lower output power will be lower. But then, it's likely to still be higher than if you ran the same regulator off a lower input voltage. So yeah you do get to design differently with linear and with switching regulators for efficiency - for a given output, you normally want the input voltage of the linear regulator to be as low as possible, while you want that of a switching regulator to be as high as reasonable, usually quite a bit higher. Edit: waaaait there appears to be a "bug" in gate control in there somewhere. Well, it's an analogue artefact rather than what you'd normally consider a bug, chances are, the control voltage or gate charge/drain current depends on the output voltage such that at very low output voltages, it can't pull the gate hard, so it is operating a large part of the time in linear mode.
Do they specify the allowable input supply ripple? I'd like to use a transformer (& bridge) that I have, but if I have to regulate it, it won't be worth it.
I wonder why it doesn't come with a 220-36V AC-DC converter. It is relatively difficult to find a 36V+ power supply lying around. And if I already have a bench power supply that can output 36V, what the hello do I need this for?
Probably because that module and a power supply would already make a complete device rather than a kit, and it would be subject to more stringent standards and also shipping would cost a lot, and also good power supplies are expensive. But you can actually just get any old AC transformer 24V or 12V/0/12V and once you rectify it and smooth it with some nice capacitors, the voltage will be 33V, not too bad eh? It will dip and get wavy under load, because it's not regulated, but then you have this programmable DC supply module, yes? Also maybe you're just a tad too ambitious for the little money. I mean you can get a 24V power supply with shitty regulation for very little money - and it's not so good that i would even trust it to go its rated 100W without exploding and connecting you to mains, so while you can obviously just fudge the feedback to get it to higher voltage, i don't think you should. Most electronics projects will be just fine having a very good regulated benchtop supply which can go to maybe 19V, that's plenty, and an ability to go to 4A or limit it to 100 mA to avoid things exploding when there's a short is great.
Dear Clive, try google "high pass filter equation" look at stuff like www.electronics-tutorials.ws/filter/filter_3.html WEB is a customer self service kind of place! ;)
Ok, I'm so so at this stuff too. Dave, your knowledge is quite impressive and illuminating. If a hobbyist joe like myself adds low pass filtering to this unit ... it is going to affect the efficiency isn't it? There will be higher loads on the power supply? I'll just have to investigate when unit and scope are in hand to see what these noise characteristics are like etc.
Efficiency will be horrible at low power outputs because the unit has a base load powering the controller and LCD module. Interesting how these modules seem pretty well designed despite being super cheap, yet a certain popular test gear manufacturer seems unable to design a good PSU for their own equipment!
Yep, I have to say though, I'm rather impressed with peak efficiency! If I got 96% from my PSU design I'd be more than happy with it. Makes you wonder what amazing things will appear in the next few years. Lots of huge bang per buck things appearing now, and its great that beginners and newcomers to electronics have this sort of gear. Electronics is now well and truly coming back from the dark days!
So knowing I'll be using the 20V 2A version (DP20V2A) in 3V-9V range I better get a 12V supply for it rather than a 20V one? Interesting. I thought it'll work better when provided more voltage to work with. Alrighty then.
If you push the rotary encoder while setting the volts and amps you can skip to higher digits and dial in 0.1 or 1.0 increments
Schwuuuuup , right Dave did not read the manuel.
illchmann you got a manual?
Schwuuuuup, yes we, Dave and I, have a manual.
illchmann Can we pay more for the automated instruction guide? Manual seems a bit twentieth century.
0:25
here you can see it... ^^
I bought this one as I wanted a mini suitcase with all necessary tools for an electrical engineer.. I have to say, I didn't look much info about it and I just trusted my gut feeling when buying this, and I was very very impressed by it, especially for the price!
Now I have a suitcase with this mini DPXXX PSU, the ATMega328 based transistor+component tester+frequency generator(pwm) thingy, DSO138 based mini digital oscilloscope (for low freq simple stuff), a "no-name" Logic 16 logic analyzer + rasperry pi zero with screen to run it on (+mini keyboard,mouse), Yihua adjustable temperature soldering iron (amazing), small ESD mat, glue gun, couple of multimeters.. and many many other stuff.. all that inside a small suitcase and I easily spent less than 100€ (with shipments) for all those stuff, haha!
Thank you China for letting us poor electrical engineers to have our gadgets! :D
venim1103 Cool! :*)
yeah I got mine as a portable and small power supply unit as well, it worked like a charm was worth every cent of the 30 bucks I paid for the 5A buck-boost version.
Pics or didn't happen
Make a quick video on your cell & post it. I am working on similar with a ridid tool organizer as the frame, dso150 kit, yaogong rework soldering iron/heat gun & would love some ideas on how to organize it😉
Yeaaahh... very helpful video, these little buck modules are super neat and super handy, thaaanks for spending time characterising it, this will help a lot of people out there!!
they are awesome RD is criminally underated (although they probably got quite a lot of extra orders from this exposure :P)
Press V or A to select Volts or Amps, then press the knob to select which digit you want to adjust. Even better.
I really like how Dave covers the entire test equipment range, from "Don't Waste Your Money" to Unobtanium. For a useful instrument at the low end, Dave's highest praise tends to be something like "Not a Complete Waste of Money".
Hearing Dave glow about $20-$50 power supply modules induces blurry double-vision with Rod Serling talking in the background over the Twilight Zone theme.
Which means the world's supply of these modules is about to vanish...
get them while you still can!
4 years later, still plenty on eBay.
Thanks for this detailed test of the module. As I and others pointed out in your previous video, you can adjust the voltage and current more quickly, while in the voltage/current adjustment mode, you can press the rotary encoder button, which will move the cursor to 0.1, 1.0 or 10v per turn. It's of course also mentoined in the manual.
I was very happy to discover that when setting the voltage and current on the main page of the DPS3003's user interface you can push the pot button and select different digits in front of or behind the decimal point to speed up the value selection you want.
yes, there is short-cut setting
thansk dave. my 5005 have 96% too (12v 3a output). now i want to see the buck-boost model. cheers
Poyectos LED seria genial traducir estos videos
Julian Gomez
Dejate de joder q a Dave se le entiende perfecto el acento australiano. Mejor aprende ingles asi no necesitas subtitulos y si estas aburrido haces los subtitulos vos.
the buck-boost model works like a charm too, doesnt really even get hot enough for the fan to go on, even when pulling several amps at lowish voltages. and best thing is it works off of almost any dc power supply so its super portable as well.
Very helpful, I am thinking of purchasing 2 of these and connecting to center taped transformer with bridge rectifier to obtain negative and positive output supply. I also like the out On/Off. Can see the importance of output filtering. Great video love your all encompassing explanation - thanks
It may be that my glasses needed cleaning, but this video looks extra crispy and contrasty to me... Great content and very interesting little module. I was just researching the viability of making a quick and dirty PSU with a boost/buck converter and a LCD multimeter. This seems more compact and with many more functions!
Interestingly I managed to order a DPS3003 for AU$18.98 delivered, shortly after Dave's first video. But I now see the same listing has been bumped up to AU$28.80. These ebay sellers must love Dave!
Hi Dave Did you subtract the base power from the input power? If not then this makes them look very bad in terms of conversion at low output power (although the overall efficiency calculation would still of course be correct).
Dave, can you do a video on creating a filter to smooth the output. Inductor inline or a capacitor across the output?
Yeah!
Just putting a 1 or 2 mfd. tantalum cap paralleled with a 0.1 mfd ceramic should go a long way to knock down the noise.
filter combined with inductor and small tantalum capacitors should smoth the output perfectly. this kind of filtering to get rid of ripple and noise is commonly use in pc power supplies and does decent job! ;) I waiting for my DPS5015. great job Dave, thanks for your efforts to characterize this nice kit ;)
Great 3 minute Video! (I think the right arrow key was invented for Dave's videos!). I also see by the comments that many viewers need a basic refresher on "reverse engineering" LC filters. Actually, no need to "reverse engineer" anything since the Regulator IC's Data Sheets and APP notes have it all!
Cool. Thanks for taking the time to go through that tedious process to get the data!
To set the voltage press V turn the knob to change value press in on the knob to select the decimal place the same setup is used for the current. MI and M2 are used to save settings and recall settings. You can also save and recall more settings if you use the set button.
Thanks Dave I've been looking for a module like this so your video helped me make my mind up as to which one to buy. Just ordered one from ebay thanks again
Better than my Philips Rack PSU.
Hasn't been calibrated since 1990... The output is very unstable. And it weighs a ton.
It was a freebie, I'll fix it someday soon.
You'll never fix it until it blow up
someday ey
Dave, If you push the encoder while changing voltage or current on the home screen, the resolution will switch from 1mv increments up the scall with every push.
A great voltage supply for these units are old stereo receivers. For less than $20 here in the US you can get a unit from Goodwill or Salvation Army. You'll get a big transformer usually with multiple taps, and a bridge rectifier, and a big input smoothing cap for dirt cheap.
It seem like a very good little piece of hardware, and considering the price, im amazed :-)
Dave I don't know how I feel about you actually liking a cheap product! Great stuff as usual
I like these not so high end stuff videos, keep them coming :D
Thanks for doing this Dave. Saw these a while back and wondered if they were any good. I'd say they are a great value for the budget limited lab like mine.
If you are in the current/voltage set mode on the main graphis screen and press in the rotary encoder knob you change the cursor position so you don't have to only adjust the 10mv range, or 1ma range.
I would definitely like to see a reverse engineering of the design, would be very interesting.
If only there was a meter that could measure voltage and current & output over, say, Bluetooth so you could automatically plot the efficiency curve...
Not without automatically controlling your PSU source, load, and PSU under test as well unfortunately.
Moshimeter!!!!!!!!!
Is that a challenge?
yzxstudio monitors also have bt options. Also check out powerz king meter, that one is around $50 but even more options like micro oscilloscpe function.
I feel like you could probably hack something together using the red pitaya...
Dave, that power supply module you have is indeed remote controllable! Check out the RX/GND/TX header you revealed when you did the teardown.
I ordered two DPS5005 just because of your first video and i also have two seperate 48V/4A Mains powered SMPS in order to build up a two independent outputs power supply for OpAmps or alike...
Anyway, the heatsink will get heated up the most when i run the module with a rather low output voltage but high current.
I hooked up my two 4Ohm/1kW dummy loads in parallel, set the maxinum current at 3.8Amps and let it run...i also had a temperature meter on the heatsink and it settled at about 50degree C with the module sitting on my bench....so if you put it in a housing it may is a good idea to have a (temp controlled)fan inside or it might overheat....
Otherwhise i have no problems found, jet. No short circuit issues, or suddenly disconnect the DUT while running at full ouput current...nor a big Cap and output switched on/off/an...the same goes for a one Henry/5Amp inductor (EI-130 core)
The only thing i did not test was feeding in a reversed voltage from another power supply...as this is not a four quadrant Power Supply, i don´t know if it gonna survive...but running with the usual load conditions it does the job quite well, regarding the money i spent on them...:)
Thanks for showing us power supply guys some love
I Ordered 50V 5A and LED SMPS 48V 150W, 2 weeks ago, stil waiting to arrive. I also planned to put filters (common mode inductors and caps on both sides), filters will go between SMPS - converter (higher cap values, ceramic and elco) and converter - load (low cap values, ceramic).
If you click the knob you can change what digit you are spinning up or down. At least on the higher current model I have the knob is also a button.
Hi Dave, once you are in amps or volts push the encoder wheel to cycle across digits you want to change. I use 2 DPS5015 and it's super easy and fast to set it.
I have the dsp5005 (50v 5A) it has the same small form factor and was 21€ delivered.
Click that rotary encoder to change unit digits while setting voltage/amperage.
I know right ... im amazed he hasn't figured it out yet
Maybe the low efficiency comes from the schottky diode used to do the freewheeling. At low output current and voltage the mosfet is off most of the time so it's the voltage drop of the diode that creates losses. They could have improved that with a synchronous design using a second mosfet instead of that diode.
I liked this video. I'd like to see how fault tolerant it is though. How does it respond to shorts? Any thermal protection?
Jake Heuft the bigger modules habe OTC protect..
Reverse engineer it and try out some options to improve the output ripple!
No need to reverse engineer for that, just add the desired filter
What is a desired filter ? Howto choose/design one ? Could be a nice video follow up.
What Dusan said. What could be a desired filter? Measure frequency response/step response... do some actual engineering. Efficiency measurements and such in this video are a great start :)
Noise. From experience, what applications would the noise of this device be an issue. What hobby related apps would one run into problems. For example are esp8266's, or the range of Arduino products or an old 1981 Galaga PCB on the repair bench susceptible to noise. How would you determine if you are close to the edge.
TheSignalPath offered a solution to reduce noise but when would it be necessary in general hobby apps.
I've recently used the big brother of this module (DPS5015 50V 15A, 35$ on Ali) and a power supply pulled from a Cisco switch (Cisco DS-CAC-845W, going for ~20$ on ebay and doing 52V at 17A) to build myself a benchtop lab power supply that finally has some Oomph to it.. and I'm really liking it. Just needed a few more µF on the output side.. it's a little bit underequipped if you go into the double-digit amps.
Did you take apart the Cisco switch and use your own enclosure? I'm thinking of getting the 3005 or the 5015 but I don't want the PSU to take up so much space.
The mentioned Cisco PSU is a modular unit that has outputs through a big Molex-type connector. For the complete project I used an old external SCSI drive box where the PSU module fit just in, after minimal dremeling.
Thanks, that s a lot of time and effort you have gone through,
@EEVblog The manufacturer is Hangzhou Ruideng and there is a modified firmware available called OpenDSP created by Johan Kanflo so you can optimize it for your needs.
Here are the different PC softwares for it and also the documentation of the communications protocols (in chinese, but google translate handles them fine):
www.mediafire.com/folder/3iogirsx1s0vp/DPS_communication_upper_computer
Interesting that the 1.5V output loses so much power. I wonder if it's related to the fact that in the previous video you said the chip they're using isn't really designed for down to 0V output. Perhaps some odd behavior it does at low output voltages, regardless of input
btw, you don't really need 4 meters. You can also use two meters with break-before-make switches in a clever circuit.
Also, a lot of times the graphs are with log scales
Another awesome video would be to use a step-up converter like the AT30 or XL6009 module to power one of these at maximum voltage from 5-12V. Even more, these step-up converters can be probably bootstrapped to be isolated with just a coupling inductor, a capacitor and a schottky diode.
Neat little unit. Just in some digital output lines to control series/parallel switching of transformer windings and it would be almost perfect!
Ordered the DPS3005 from Banggood after your last video. Will be great to finally have a 'proper' (!) bench supply. Thanks for the tip Dave.
congrats on having a "proper" bench supply.
You can never have enough power supplies. Spend some time in making a nice enclosure for it. :-)
I fully intend to; gonna stick a switched and fused IEC C14 on the back and hook that up to a laptop power brick internally, as well as the obligatory cooling fan. Not sure what old chassis I'll re-purpose for this. Perhaps an old PC PSU...
Dave Compton oooo. The laptop power brick is not a bad idea... might have to borrow that one. Otherwise, I'll get a toroidal transformer to drive it.
dave after pressing the voltage or current button you can push the silver button in to change from 0.01ma/v to 0,1 to 1 !
mondayfool its annoying to give dave an info he didnt know? Jesus
Could you do a video on filtering the output for people doing audio or radio work with their bench supplies? I know some audiophiles who insist only linear power supplies can provide pure DC. I also know that's bs.
Dave were there any Load Line Regulation measurements taken to quantitative how well the output held up under various output currents? Those figures along with output noise used to be some of the first figures I used to use in evaluating power supplies.
What value capacitor would I add to this to filter out the noise on the output? And how to determine that value?
I had the same question. A quick Google search suggests a lot of math is involved but I have a feeling there's a rule-of-thumb like "toss a 0.1 µF cap across the terminals."
theres is probably way more then 0.1uF on the output internally .... it also matters what kind of cap you are using and its ESR, a electrolytic cap is hardly going to filter out the hf switching noise at all.
Michael Eckl off the top of my head, I'd use a bunch of 1uf ceramic monoblocs (bypass caps) in parallel. (The issue here is noise, not ripple.) If I was still seeing noise under max load, add a few 47-100uf low-ESR electros or tanties.
I see a lot of suggestions for parallel capacitance here, but no mention of series inductance or resistance. Aren't these also needed for a filter?
Possibly it would be best to have capacitors, followed by inductors (or a common-mode inductor), and then a bit more capacitance. You see this kind of arrangement in fancy power supplies on their AC input to stop noise getting on the power lines.
Hey! :*) Rd Tech (the developer) now offers communication versions.
In your previous video, I thought 96W was bullshit. That little module is impressive.
The thing I don't like about these is they are DC/DC. I would like to see one that comes with a bridge rectifier, so you can couple it to a transformer. That way you can plug it in like a true bench supply.
Thanks Dave! I'm considering buying one.
Maybe characterise the Buck-Boost one?
If it does well, it is a no brainer for me. I have a spare PC PSU, laptop psu, and a few transformators, so getting some DC input wouldn't be hard.
7:12 VOOOOOOOOOOM!
how quick.will they put prices up now Dave's done a couple of videos I think 25%increase. 50v 5amp £21.42GBP current price
I doubt it.
There's too many people selling them.
There's lots of sellers for these PSUs and, yeah, some sure will change the prices. That's why it can be a bad idea to buy a product by clicking a link under a video or in a forum.
But checking the orders on Aliexpress for the DPS5005, Dave already increased the sales 10-fold with the first video a few days ago. They sold less than one a day before that, but there've been around 60 orders during the last 6 days since oct.5th. Do you have the price from a week ago? Because if they react to the increased demand, they sure will have done that already.
well for one thing they are going to run out of stock rather quick I think ;D
I don't think you lot can make a dent in China's manufacturing capability at this point. Seriously, they can mobilize thousands of people putting those things together 24/7 overnight if the sales are there. Efficicency is easy when you don't have unions or overtime regulations.
Dave, did you checked OpenDPS firmware? You can manage then this device over wifi even (if you attach ESP8266)
Why didn't you do 3.3 volts?
Exactly what I was thinking. It would have been quite interesting to see where the 3.3v curve was positioned between the fairly nice 5v curve and the significant less efficient 1.5v output. I'm guessing it may be a lot closer to the 5v curve than the 1.5v curve.
I remember doing that at school over and over again…
You put in the time for this one, really interesting. What I’m interested in is the accuracy of the voltage under load - does it dip as the amps go up?
If you used a lower input voltage (for ex 5V), would the efficiency of the 1.5V output improve? I.e. if you want better efficiency for the lower output voltage ranges, is the solution to decrease the input voltage?
This is off-topic, but what can you say about Libre Office, specifically the spreadsheet, as compared to Excel?
nice to see the followup dave! .... did you finally figure out how to easily set the voltage and amps with the encoder and V/A buttons by the way? ;D
Dave, why you don't measure Load Transient Response? Please, it should be easy, and very helpful!
Greetings from Poland!
They only sell in usb and blue tooth options! There is no serial or wifi model i i think! I will buy the dsp5020 with usb out put!
hey dave, can you do some quick and dirty output filtering on this module please?
Very nice demo.
Would this module work if powered by a 18V 7A AC Transformer? Thanks
I wonder how the 1.5V curve would be if the input was something like 5V. Buck converters aren't that good for lowering too much like you tested (Vout = 10% Vin).
Great Analysis Partner.
Nice analyses, not the best PSU replacement but Bob's your uncle!
What kind of filter do you recommend on the output?
RTFM, dude! Lol. That wonderful little device is far easier to use ;-)
please dave , a reverse enginnering of this module will help all the guys who have a faulty unit (like me) and will protect others when their module fails.
1.5v??? Where is 3.3v?
Please do the buck boost model next!!!!
So.. Next how to clean output. Without awfull shortcircuit current spike. And howto use this charging without diode and voltage drop. This is not protected if voltage is more that device output.
10:50 The DaveCAD lifetime license precludes the use of Excel? Some weird clause in the EULA? :D
just got my usleeve awesome thanks!!
Please make a video about filtering the output noise!!
No need. ruclips.net/video/DPN1BERe6cg/видео.html
dave replied on this video saying that video is a poor way of doing it.
In fact dave got some poor videos too, but that is not the case, there is only one good solution if you want lab power supply with low level of noise and that is linear regulated supply.
Bartłomiej Z z@
I was hoping that 1.5 V would have lower power consumption, but that saving is turned into heat. So the device cant scale down its power? Is this about the design and the nature of electricity. Could you design it so the input voltage (force) is decreased, but then then it still needs a different circuit for max efficiency I suppose?
ruclips.net/video/ZKz9zsH-wWs/видео.html
Would have been useful to measure the temperature of the heatsink at the same time - at least at the extremes? Also, spend 5 minutes detailing exactly what you can do to smooth out the output - adding capacitors etc. Whilst this is second nature to yourself and all experienced hobbyists it won't be to newbies (the type of person likely to be most interested in aquiring a cheap bench PSU). Anyway, anither great vid so thumbs up from me :-)
Great video, thanks Dave. But I’m not sure why someone would want a variable DC power supply that requires a DC power supply in the first place.
You can use it with some old 19V laptop psu.
for our DC-DC power supply, we can design it better and add more function, you just add some simple AC-DC power supply, that's ok. if you find AC-DC power supply directly with same function, it will be more expensive , and many people want to do a DIY power supply . different people have difference needs
@@mikapirinen5561 yes
I was under the impression that the power loss that increases at lower voltages would be a characteristic of the Linear Regs, with the switching ones not burning that power since its switching.
But every time the output switch changes state, the gate of the output MOSFET needs to be charged or discharged, and temporarily the MOSFET is operated in a linear region for a very short time until the gate reaches the new control voltage. Because this happens at fixed frequency, this consumption is nearly independent of output voltage but you can assume it to be close to constant, which means nominal efficiency at lower output power will be lower. But then, it's likely to still be higher than if you ran the same regulator off a lower input voltage.
So yeah you do get to design differently with linear and with switching regulators for efficiency - for a given output, you normally want the input voltage of the linear regulator to be as low as possible, while you want that of a switching regulator to be as high as reasonable, usually quite a bit higher.
Edit: waaaait there appears to be a "bug" in gate control in there somewhere. Well, it's an analogue artefact rather than what you'd normally consider a bug, chances are, the control voltage or gate charge/drain current depends on the output voltage such that at very low output voltages, it can't pull the gate hard, so it is operating a large part of the time in linear mode.
Do they specify the allowable input supply ripple? I'd like to use a transformer (& bridge) that I have, but if I have to regulate it, it won't be worth it.
if you use AC-DC converter or transformer coil, please add rectifier (rectifier bridge) and filter (more than 4700uf filter capacitor)
I wonder why it doesn't come with a 220-36V AC-DC converter. It is relatively difficult to find a 36V+ power supply lying around. And if I already have a bench power supply that can output 36V, what the hello do I need this for?
Probably because that module and a power supply would already make a complete device rather than a kit, and it would be subject to more stringent standards and also shipping would cost a lot, and also good power supplies are expensive.
But you can actually just get any old AC transformer 24V or 12V/0/12V and once you rectify it and smooth it with some nice capacitors, the voltage will be 33V, not too bad eh? It will dip and get wavy under load, because it's not regulated, but then you have this programmable DC supply module, yes?
Also maybe you're just a tad too ambitious for the little money. I mean you can get a 24V power supply with shitty regulation for very little money - and it's not so good that i would even trust it to go its rated 100W without exploding and connecting you to mains, so while you can obviously just fudge the feedback to get it to higher voltage, i don't think you should. Most electronics projects will be just fine having a very good regulated benchtop supply which can go to maybe 19V, that's plenty, and an ability to go to 4A or limit it to 100 mA to avoid things exploding when there's a short is great.
I was thinking this too! Probably just cost.
Do you still have thos macs you got in the dumpster?
So this power supply itself needs a power supply?
I need to get myself a few of these..
So Dave, are you going to apologise to the makers for being sceptical about the adequacy of the heatsinks in the first video? ;)
NEVER apologise for being sceptical.
If I were to glue a breadboard on top of a plastic project box, with one of these converters in it, would it create significant noise in my circuit?
Jordan Waughtal put an filter to your NEEDS!
I want to see a video on the OpenDPS firmware
Thanks Dave!
What input voltage do you recommend for 5v 2.5a output? Will it always be around 90% efficient?
Looking at those graphs it looks like a few volts above output is most efficient. So maybe 8V in to get 5V out
That's what I assumed too. Thanks!
Dave, does the noise change much over range of power input to output or is is pretty much 100mV at it's worst?
Haven't fully characterised that, but I think it's mostly a function of output current.
Dave, i love these dc-dc converters. Please could you explain how to filter out the noise on these things?
Dear Clive, try google "high pass filter equation" look at stuff like www.electronics-tutorials.ws/filter/filter_3.html WEB is a customer self service kind of place! ;)
Oops.. you want 'low pass'. :P
Ok, I'm so so at this stuff too. Dave, your knowledge is quite impressive and illuminating. If a hobbyist joe like myself adds low pass filtering to this unit ... it is going to affect the efficiency isn't it? There will be higher loads on the power supply? I'll just have to investigate when unit and scope are in hand to see what these noise characteristics are like etc.
OMFG, a video without saying 'in like flin', im fucking shocked.
Efficiency will be horrible at low power outputs because the unit has a base load powering the controller and LCD module. Interesting how these modules seem pretty well designed despite being super cheap, yet a certain popular test gear manufacturer seems unable to design a good PSU for their own equipment!
The efficiency is terrible even (as I did) taking out the quiescent module current. Just the nature of the beast.
Yep, I have to say though, I'm rather impressed with peak efficiency! If I got 96% from my PSU design I'd be more than happy with it. Makes you wonder what amazing things will appear in the next few years. Lots of huge bang per buck things appearing now, and its great that beginners and newcomers to electronics have this sort of gear. Electronics is now well and truly coming back from the dark days!
So knowing I'll be using the 20V 2A version (DP20V2A) in 3V-9V range I better get a 12V supply for it rather than a 20V one? Interesting. I thought it'll work better when provided more voltage to work with. Alrighty then.
DP202A is very very old version, DPS3003 is new version, we use new desing way to make it safe and better
Graph efficiency vs. voltage below input supply.