EEVblog #1265 - $53 360W Lab Bench PSU! - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: November 27, 2019, 10:54:27 pm
content: Review of the $53 Riden (RD Tech / Rui Deng) RD6006 360W bench lab power supply module with WiFi connection.http://s.click.aliexpress.com/e/DlHrJpFS

author: thm_w
author_rank: Super Contributor
timestamp: November 27, 2019, 11:14:06 pm
content: Test gear thread:https://www.eevblog.com/forum/testgear/ruideng-riden-rd6006-dc-power-supply/$53 not including a case or AC-DC PSU. But in my case neither of those were needed, so the price was valid.

author: Bud
author_rank: Super Contributor
timestamp: November 27, 2019, 11:38:32 pm
content: Horrible noise. Would only be good for basic digital circuits or a coffee warmer.

author: thm_w
author_rank: Super Contributor
timestamp: November 28, 2019, 12:10:06 am
content: Quote from: Bud on November 27, 2019, 11:38:32 pmI haven't watched it yet but he is measuring the pulse height at:24:54 ~500mV p-p with no load25:34 ~550mV p-p with 5V and 1A loadI didn't measure anything close to that, it could be coming from a bad source PSU or related to the rigol load and external EMI.I'm seeing pulse heights of:<100mV p-p no load 5V75mV p-p no load 25V160mV p-p 5V 6AMy source PSU = 30V meanwell so not directly comparable to his setup. I'm sure another owner with 60V source can comment. Or you can measure it fed with a linear PSU to eliminate source PSU issues.

author: floobydust
author_rank: Super Contributor
timestamp: November 28, 2019, 12:31:59 am
content: What is the relationship between RD6006 PSU input(-) and PSU output (-) and digital ground? All connected together? In other words, how is USB-ground related to the PSU output (-)? I wondered if it all is floating, including the Meanwell.The DPS modules have an N-ch MOSFET switch at the (-) output (to allow battery charging, no backfeed) which can cause a lot of confusion or a ground fault if the USB port/Serial is earth-grounded to a PC, and you switch off the module you still get current flow.I've added chokes + Y-caps to lower (DPS) noise but without remote-sense, you get sag under load so it was not a great idea.edit: the RDENG USB boards have isolation.

author: amspire
author_rank: Super Contributor
timestamp: November 28, 2019, 01:01:03 am
content: I have had a power supply die when charging 12V lead acid batteries and the mains fails. The current from the battery goes back into the power supply to release the magic smoke. It could be that the Battery charging mode has a series diode or mosfet with sense leads after the diode.

author: thm_w
author_rank: Super Contributor
timestamp: November 28, 2019, 01:20:35 am
content: Quote from: floobydust on November 28, 2019, 12:31:59 amWhen its off I'm not measuring a connection, you'd have to look at the PCB to see whats connected. Earth ground shouldn't be connected, meanwell PSU is floating.I did not measure any resistance between USB ground and (-) output terminal.You can see in SDG's video at 12:23, the USB is isolated from the rest of the board. They use a CH340 (U11) then some isolator chip (U13)?QuoteThis PSU has a dedicated battery output and a relay on the +, so it should not be an issue.As for the noise, you might be better off adding filtering on the input.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 28, 2019, 01:20:50 am
content: A 20V, 18A version would probably be more useful for use with general purpose electronics - just enough to cover powering laptops and mini desktop PCs. Of the hobbyist uses for voltages between 20V and 60V, audio is the only one I can think of that's very common.

author: EEVblog
author_rank: Unknown
timestamp: November 28, 2019, 01:22:13 am
content: Oops, I goofed the noise measurementIt's actually about 60mVp-p no load and about 100mVp-p at 6A using a proper scope probe in X10. I was using a BNC cable with banana plugs and forgot the 50ohm series matcher. Oops. Will have to do another video showing this. Good excuse for a video on this topic anyway.

author: EEVblog
author_rank: Unknown
timestamp: November 28, 2019, 01:25:05 am
content: Quote from: floobydust on November 28, 2019, 12:31:59 amUSB seems isolated from the front panel ground.

author: johnlsenchak
author_rank: Frequent Contributor
timestamp: November 28, 2019, 03:11:23 am
content: DaveBeextremely carefulwith downloading files from China, they are notoriously for containing malware and other malicious garbageAnyway, another video on measuring ripple , load , and line regulation over the voltage range would be great. Even putting the DC-DC converterunder full load for a period of time would be awesome.Or doing aHI-Pottest on the DC-DC converter from the input to output to see of their is good isolation would be good test

author: sibeen
author_rank: Frequent Contributor
timestamp: November 28, 2019, 03:24:17 am
content: Is there a chance that when in battery charging mode the unit starts off in constant current mode, 0.5 amp in the video, and then when it hits the set voltage, 1.5 volts, it then switches to a constant voltage mode?It should do.

author: EEVblog
author_rank: Unknown
timestamp: November 28, 2019, 04:24:43 am
content: Quote from: sibeen on November 28, 2019, 03:24:17 amIt does change modes, buy any PSU will do that with a set voltage. There is a discrepancy between the charge display value and the read display value too, not a good vibe.Apparently it cuts off at 10% current level.

author: thm_w
author_rank: Super Contributor
timestamp: November 28, 2019, 06:04:29 am
content: Quote from: johnlsenchak on November 28, 2019, 03:11:23 amIt seemed to overheat in the vid. Even 90% efficiency at 360W, I don't think that little fan can deal with anything close to 36W. 360W is more of a peak rating presumably.There is no DC-DC input to output isolation. You are relying on the source PSU isolation, which in the case of Meanwell is going to be very good (3kVAC):https://www.meanwell-web.com/content/files/pdfs/productPdfs/MW/RSP-320/RSP-320-spec.pdf

author: BravoV
author_rank: Super Contributor
timestamp: November 28, 2019, 06:13:55 am
content: I wish the next/future variant, they will come out with linear pre-regulator (good designed one of course), and even with 20 bucks price increase, definitely I will instantly jump on it.

author: james_s
author_rank: Super Contributor
timestamp: November 28, 2019, 08:07:27 am
content: Quote from: NiHaoMike on November 28, 2019, 01:20:50 amLots of 24/28V gear out there, large trucks and aircraft are 24V. I have quite a few different 24V devices kicking around.

author: BravoV
author_rank: Super Contributor
timestamp: November 28, 2019, 08:24:13 am
content: Quote from: james_s on November 28, 2019, 08:07:27 am+1 , and if you look hard enough, especially in big cities where the cellular network gets upgraded often, think of GSM/AMPS era up to current 4G or even 5G, here what I scored few years ago from local contractors that were constantly working/upgrading cellular base station towers.Still have 6 of these gathering dust in my closet scored cheaply from them.

author: Black Phoenix
author_rank: Super Contributor
timestamp: November 28, 2019, 09:30:07 am
content: Dave, not related with the product in question, but what kind of stackable leads are you using?I said that because they are close to what I find for sale in the Huaqiangbei Electronics Market in Shenzhen, and wanted to know if you build themselves, if you bought them from Aliexpress or from another shop like RS Electronics or Farnell.

author: johnlsenchak
author_rank: Frequent Contributor
timestamp: November 28, 2019, 11:27:29 am
content: Many years ago , I worked for a company that was dedicated to making switch mode and linear power supplies for the telecommunication market mainly for companies like "Tie Communication" that who made PBX phone systems. Doing Hi-Pot testing across the primary to secondary and also primary to ground was a real important test after hours of burn in testing . It was something to see those power supplies take thousands of volts of short pules of abuse to verify that the switch mode transformer would not short over and fail Now in days you see isolation slots in the PC board between the primary to secondary, back then when you hit the test button you risked a nasty shock if you didn't pay attention to what you where doing . I strongly believe that this type of testing is a good indicator of the quality of the power supply since it proves isolation and therefore the safety of device when under load conditions

author: Kleinstein
author_rank: Super Contributor
timestamp: November 28, 2019, 12:39:45 pm
content: Quote from: thm_w on November 28, 2019, 06:04:29 amThe efficiency depends on the output voltage. With high output voltage the losses won't be so high, as the efficiency will be much higher. So at 360 W out and thus some 60 V a d 6 A efficiency would be more like 98%, as most of the power just goes though. The worst case is more like 60 V in and 25 V out.The switching ringing at the output looks pretty bad. It is kind of odd to have so infrequent pulse and the main ripply looks like faster in between.The use interface on the other side looks pretty good.

author: SparkyFX
author_rank: Frequent Contributor
timestamp: November 28, 2019, 02:14:31 pm
content: Now the burning question:will the µSupply beat it and in which points?I kind of search for some mobile power supply for stuff like Startrackers or Timelapse cameras and such.

author: tmf
author_rank: Contributor
timestamp: November 28, 2019, 03:16:42 pm
content: $44 on banggood now...https://www.banggood.com/custlink/3vKGbv6WUqjust ordering one now...I do a lot of car electronics, so might just get the small case and add jacks so I can apply the 13.8V car battery, this gives me enough current and power to do my work.Hope uSupply (is that what it is going to be called?) works better.RichardS

author: TurboTom
author_rank: Super Contributor
timestamp: November 28, 2019, 03:32:17 pm
content: Quote from: Kleinstein on November 28, 2019, 12:39:45 pmThe worst scenatio of a basic buck converter which -- as it seems -- the RD6006 contains in its power section, will be maximum input voltage and minimum output voltage at maximum current.This means full inductor losses (due to the high current and high frequency components in the signal involved), highest free-wheeling diode conduction losses (it seems the RD6006 doesn't utilize synchronous rectification but a schottky diode instead) since it's almost all the time carrying the current, and highest switching losses in the MOSFET. The latter is probably the smallest contribution factor of all this dissipation. Conduction losses in the MOSFET are usually also rather small in comparison, regardless of the duty cycle.At an output voltage of half the input voltage, the situation is much more benign regarding diode losses since it's got to conduct the current only 50% of the time.

author: dcac
author_rank: Frequent Contributor
timestamp: November 28, 2019, 03:43:12 pm
content: I'm not very impressed by the fuse installment on that Mean Well PS.

author: capt bullshot
author_rank: Super Contributor
timestamp: November 28, 2019, 05:17:55 pm
content: Quote from: EEVblog on November 28, 2019, 01:22:13 amStill in the ballpark of "horrible noise", no good for analog stuff. But you're right, the noise visible on the scope way way above the expected 100mVpp (as shown somewhere within the manual). From my experience, there're many people around not knowing how to measure the ripple correctly, so go on with the topic in a video.

author: JohnnyBerg
author_rank: Frequent Contributor
timestamp: November 28, 2019, 05:21:18 pm
content: Just ordered one. I work mostly on Li-ion based projects, so the noise does not matter (much).I find the case very interesting, could be the base for some other projects

author: Xenoamor
author_rank: Regular Contributor
timestamp: November 28, 2019, 07:55:36 pm
content: Quote from: JohnnyBerg on November 28, 2019, 05:21:18 pmIndeed. I'm half tempted to buy one just to gut to put my own DIY supply in, seems kind of wasteful though

author: buzzybee191@gmail.com
author_rank: Newbie
timestamp: November 28, 2019, 08:08:30 pm
content: Before aliexpress runs out, here is another supplierhttps://www.banggood.com/RD6006RD6006-W-Digital-Control-Switch-Adjustable-Power-Supply-DC-Stabilized-Power-Adapter-Buck-Module-Monitoring-Power-Supply-p-1587151.html?rmmds=mywishlist&ID=6279943&cur_warehouse=CN&p=K6282137007969201907&custlinkid=706783

author: Marco
author_rank: Super Contributor
timestamp: November 28, 2019, 08:25:38 pm
content: On the RD Tech channel he shows how to take it apart BTW. Just need to desolder the front panel jacks, the solder being the only thing holding them in place ...Brave desoldering technique by the way.

author: firewalker
author_rank: Super Contributor
timestamp: November 28, 2019, 08:30:54 pm
content: For the other modules (DPS5005c), there is documentation for the serial protocol. I designed a controller interface with rotary encoder for setting the voltage and current. It was slow to processes the serial commands though.https://github.com/firew4lker/DPS5005-control/blob/master/Software/DPS5005%20communication%20protocol%20-english%20google%20translate%20version%20%20V1.2.pdfAlexander.

author: relax79
author_rank: Contributor
timestamp: November 28, 2019, 09:59:06 pm
content: Looks like more powerfull models coming later.

author: thm_w
author_rank: Super Contributor
timestamp: November 28, 2019, 10:19:29 pm
content: Quote from: Kleinstein on November 28, 2019, 12:39:45 pmYou are right, although total efficiency is not quite that good here. We have some inductor resistance, FET resistance, fuse resistance, etc. that will contribute to losses. Although only a few of those go directly to the heatsink.I tried:- 29.25Vin 0.459A (13.4W)- 28.25Vo 0.411A (11.6W)- 0.61W quiescent from daves vid, ~0.2R lead loss.Which gives efficiency of around 92%In SDGs video we can see:-SE100P60A25mOhm-MBRF20100CTIdeally, at 6A output Vin = Vout, we'd only see about 1W going into the heatsink due to FET losses.

author: nixfu
author_rank: Unknown
timestamp: November 29, 2019, 06:14:04 am
content: Does this really need a 60V supply? Or can I use one of the 300-400w 24V or 48V meanwell's I already have laying around from my 3d printer builds?

author: Xenoamor
author_rank: Regular Contributor
timestamp: November 29, 2019, 10:21:21 am
content: Quote from: nixfu on November 29, 2019, 06:14:04 amYou can use any power supply between 7 - 70V but it's a buck only regulator so you'll only get less than what you put in out

author: Cliff Matthews
author_rank: Unknown
timestamp: November 29, 2019, 03:59:04 pm
content: RD Tech appear to take Dave's Kudos, test's and comments seriously.They launched a video about the virus issue but the link to the new file (on Google drive) still has an issue with "RidenPowerSupply.exe" according to VirusTotal.comThese guys really need to do videos with computers configured in English.. Sometimes I think they have no idea how bad they look to the world outside of their little Chinese echo chambers. The choice of using background music designed for children was also another marketing failure...

author: Cliff Matthews
author_rank: Unknown
timestamp: November 29, 2019, 04:18:27 pm
content: Under the video listed above, I decided to check the whole RAR file from the backup site. The results are not good..https://www.virustotal.com/gui/file/18d821570731285fd276d62e5cd5a929a15ea066a9e85401db25ef43982fe71a/detection

author: nixxon
author_rank: Frequent Contributor
timestamp: November 29, 2019, 08:14:59 pm
content: Nice review and follow-up regarding the high frequency noise. Just like any other legacy fundamentials Friday.This guy made a nice effort to reuse the case and 60V 5A power supply of a badly functioning lab power supply to make a new and improved one using the RD6006/RD6006-W as a front end:

author: sixtimesseven
author_rank: Frequent Contributor
timestamp: November 29, 2019, 08:32:06 pm
content: Quote from: Cliff Matthews on November 29, 2019, 03:59:04 pmI wonder generally why these companies do not get a native speaker to either do the presentation or at the very least get them to proof read the stuff before posting it.

author: Monkeh
author_rank: Super Contributor
timestamp: November 29, 2019, 10:43:22 pm
content: Quote from: Cliff Matthews on November 29, 2019, 04:18:27 pmLooks like generic heuristic hits rather than positive malicious code. Probably false positives.Still, there's about zero chance I'd go anywhere near the software anyway.

author: buzzybee191@gmail.com
author_rank: Newbie
timestamp: November 30, 2019, 09:30:05 am
content: Before aliexpress runs out, here is another supplierhttps://www.banggood.com/RD6006RD6006-W-Digital-Control-Switch-Adjustable-Power-Supply-DC-Stabilized-Power-Adapter-Buck-Module-Monitoring-Power-Supply-p-1587151.html?rmmds=mywishlist&ID=6279943&cur_warehouse=CN&p=K6282137007969201907&custlinkid=706783

author: fandemos
author_rank: Newbie
timestamp: December 01, 2019, 03:17:49 am
content: I would like to know if someone has made any changes in this source to reduce the ripple and noise, beyond putting some capacitor, since its connectors are soldered directly to the board. Thank you.

author: james_s
author_rank: Super Contributor
timestamp: December 02, 2019, 01:07:05 am
content: Quote from: sixtimesseven on November 29, 2019, 08:32:06 pmBeats me, there is no shortage of native English speakers. For many kinds of product that interests me, I'd be willing to proof read and edit the English documentation in exchange for one of the devices to play with. Seems like they could do a lot worse with their marketing budget than that. I haven't made a serious attempt to contact any companies with that offer but the thought has crossed my mind.

author: Andrew McNamara
author_rank: Regular Contributor
timestamp: December 02, 2019, 06:44:19 am
content: Quote from: sixtimesseven on November 29, 2019, 08:32:06 pmHaving watched a few of their videos, I think RDTech is very small - maybe just a couple of engineers, and a production dept. I would suspect they just don't have the resources, or time. I'm prepared to cut them some slack - they're making interesting products, give good value, and they do try hard to support them, which is more than many western companies do. Frankly, I'd take their best-effort English over the Sweet Nothings from the average corporation.

author: Kleinstein
author_rank: Super Contributor
timestamp: December 02, 2019, 09:57:20 am
content: The output ripple is exaggerated by the probing technique, but it is still strong and odd, that there is not just the regular ripple, but some extra strong pulse at a rather low rate. This looks a little like a superimposed burst mode or some extra pulses added to the set point signal of the switched mode supply.So there is chance that the really bad strong pulses could be avoided, possibly with filtering the control signal from the front board to the power board. I would not be surprised if they use PWM plus filtering instead of high resolution DACs.

author: thm_w
author_rank: Super Contributor
timestamp: December 02, 2019, 10:40:28 pm
content: Quote from: Kleinstein on December 02, 2019, 09:57:20 amSTM32F103RCT6 has two 12-bit DACs, but thats not quite enough for the set resolution (14mV/1.5mA vs 10mV/1mA), so they may be using the PWM outputs as you say.The other parts I see:-RC04VFRAM U6- Winbond flash memory U8-GS8332350kHz single supply opamp U12-XL7015buck, fixed frequency 150kHz so noise shouldn't be related to that.-AOD2810FET (dpak not heatsinked)Most of the pulses are at 100kHz repetition, surely this is the fixed switching frequency of the TL594 right?As Dave stated, filtering the FET gate drive with a ferrite or resistor is probably going to be beneficial here. The ringing of the pulse is ~10MHz.I do see some 1kHz and 240kHz spaced pulses as well, which will be something else.edit: gate of PFET goes to via to top then R34 (10R resistor) so thats already a fair bit of gate resistance. TL594 switching frequency is 64kHz with no load.edit2: slightly improvement with 600R@100MHz bead but not massive, might need another approach or a lower frequency material. Gate capacitance = 4nF = ~4MHz RC?

author: pepelevamp
author_rank: Regular Contributor
timestamp: December 02, 2019, 10:53:17 pm
content: whats powering the display? can we get in there with an FFT on a stick and probe some points? Maybe we can find some relevant switching frequencies elsewhere in the box.

author: thm_w
author_rank: Super Contributor
timestamp: December 02, 2019, 11:33:34 pm
content: Quote from: pepelevamp on December 02, 2019, 10:53:17 pmProbably the 5V from XL semi buck chip then LDO, but I think thats not too bad. The "big" pulse is seen on the output when probing for mag field right beside the main inductor.I'll try adding a gate ferrite and update in a bit.There is a snubber (R34 (2.2R), C27) to the left of the heatsink.

author: montyx
author_rank: Contributor
timestamp: December 04, 2019, 02:48:43 am
content: Does anyone knows about any linux compatible software for the RD6006? I use linux, so it's not an option to use the official sw.

author: Mr.B
author_rank: Unknown
timestamp: December 04, 2019, 02:58:43 am
content: Following this thread. I am interested to see the outcome of research into reducing the output noise.I purchased one from the RDTech store about a week before Dave put the video up.I will leave it in its respective boxes and wait to see how the noise research goes.Thanks to those actively pursuing this.

author: ironcurtain
author_rank: Regular Contributor
timestamp: June 13, 2024, 12:54:47 am
content: Resurrecting this thread. I was testing a buffered clock distribution board powering it with the RD6006 and then went down the rabbithole of locating the noise/spurious signals.Can we put together a list of mods to lower the noise/ripple and weird pulses?