Just bought a GW-Instek GPP-4323 power supply-First impressions etc. - Page 1
Forum section: electronics / testgear

author: djsb
author_rank: Super Contributor
timestamp: March 31, 2020, 01:51:54 pm
content: Just bought myself a GW-Instek GPP-4323 power supply from ELESHOP in Holland.Cost breakdown as follows:GW Instek GPP-4323 power supply GPP-4323 1 €553.68 (£488)GW Instek GPP-series LAN card GPP-LAN 1 €30.00Subtotal €583.68Shipping & Handling €10.00Grand Total (Excl.Tax) €593.68VAT-GB (21%) €124.67Tax €124.67Grand Total (Incl.Tax) €718.35Total of £635.06. I paid 21% VAT whereas the VAT rate in the UK is 20%. Farnell quote £471 + VAT, so I could have got it for less with free postage and less VAT but no stock. SJS electronics quote £560.I will post my first impressions when it arrives.

author: djsb
author_rank: Super Contributor
timestamp: April 06, 2020, 03:48:01 pm
content: It's here and I'm happy with it. Nice quiet fan. Rotary encoder for control knob. Comes with 4 sets of leads with crocodile clips on one end and 4 mm recessed banana sockets on the other. And a green earth lead with a green 4 mm socket on the end.Nice compact size and easy to use. The annoying beeper can be turned off. The sockets are recessed but I've bought some Pomona 2894-2 and 2894-0adaptors that will allow more options.https://uk.farnell.com/pomona/2894-2/adapter-binding-post-banana-plug/dp/2526681andhttps://uk.farnell.com/pomona/2894-0/adaptor-binding-post-banana-plug/dp/2406327I've checked some voltage outputs and I'll post the minimum and maximum outputs per channel later.A bit annoying that it didn't come with a 3 pin UK IEC lead but soon remedied. Quick start guide is useless.More later.

author: pipe2null
author_rank: Regular Contributor
timestamp: April 09, 2020, 04:26:48 am
content: Yea, I'm still waiting on mine, got another month or two to go still. I just HAD to have the LAN option for my GPP-4323, even though it can only be installed at the factory... In China... In the middle of a pandemic... And I placed the order anyway in February... I'm not sure I thought that one through well enough.

author: Hydron
author_rank: Super Contributor
timestamp: September 15, 2020, 05:11:10 pm
content: I saw this PSU in a different thread and am rather tempted by it, but i _hate_ the recessed non-binding posts. So just to clarify, when you ordered it the eleshop photo showed normal binding posts, but the unit you received came with the recessed sockets? I'm hoping that their stock changed and they updated the picture, but it's probably in vain.I also quickly checked tequipment and while they have it for a decent price it wouldn't generate a shipping quote - unfortunately they probably aren't allowed to send one to the UK

author: maginnovision
author_rank: Super Contributor
timestamp: September 15, 2020, 05:59:39 pm
content: I think the EU/UK get recessed sockets and other markets get binding posts.

author: pipe2null
author_rank: Regular Contributor
timestamp: September 15, 2020, 10:07:49 pm
content: I'm in the US and received binding posts. Quite happy with this PS so far, although I haven't really used the programmable load function yet.

author: jnd
author_rank: Regular Contributor
timestamp: March 28, 2021, 10:49:03 pm
content: I just got the GPP-4323 couple days ago. TME had limited discount and it was the last in stock. The first impressions went from being impressed about the relatively compact form, well thought-out user interface and very quiet operation, to disappointment about unnecessary last digit for the not that great accuracy, to again being impressed by the low drift and stability especially of the lower range aux channels.Let's get some less well known specs overview out first:The readback resolution is 0.1 mV and 0.1 mA but the instrument is specified with horribly coarse 0.03%+ 10 mVand 0.3%+ 10 mA, both for setting and readback values, which almost nullifies the usefulness of the fourth digit beyond decimal point. In reality the accuracy is quite bit better, it seems this GW Instek is covering the imprecise zero offset and internal resistor parallel to the output which will affect the low current readings at higher voltages. The set and readback are not coupled into feedback loop, so they can both drift independently.The CH1 and CH2 are identical main outputs, 0-33 V and 0-3.2 A (so a little more over the official datasheet range) while also being able to sink 0-33 V and 0-3.2 A in load mode, being limited by 50 W total input power. OVP and OCP limits go even more beoynd that range, 0.5-35 V and 0.05-3.5 A. There's rather large 470 uF capacitor and 470 Ohm parallel resistor at the output terminals.CH1 and CH2 have internal relays to change into classic serial or parallel mode. They also have internal relays to switch over to load mode, really welcome innovation. The voltage at the jacks has to be low (<1V) or none to be able to switch between he source and any sink (CV, CC, CR) mode, otherwise it will fail with error message couple seconds later. That's perhaps why there is no front panel voltage reading under 1 V input but you can read it remotely. You can set 1.5-35 V in CV mode but if you are in CC or CR you can use the load basically down to zero or at least to very low values limited by lowest resistance of the loading circuitry. In practice I was able to sink 100 mA at 20 mV, 1 A at 200 mV, 3 A at 600 mV. That's totally usable to discharge any batteries in the available current range. The CR mode has only 1 Ohm to 1 kOhm range, so it's limited in range and resolution but still better than nothing. Unfortunately when you get back to supply mode the channel uses the same values last set for loading and doesn't go back to last used sourcing voltage and current.CH3 and CH4 look symmetrical inside but are different. CH3 goes 0-16 V and 0-1.1 A and CH4 goes only 0-5.5 V and 0-1.1 A but it's significantly more accurate and stable, thanks to higher resolution per volt of the ADC/DAC. There's smaller 100 uF capacitor and 1 kOhm parallel resistor at the output terminals.All channels are completely separate and isolated, major advantage against similarly priced multichannel supplies. From my simple test I saw no detectable change in the CH3 output when I put CH1 into source and CH2 into load mode, drawing and burning some 30 W.You can have some idea from this 10 minute voltage stability reading. The power supply values include both set+readback inaccuracies together while I'm measuring the most stable CH4 with 34401A and it's stable down to the 0.1 mV:Here are some voltage and current readings through the range with my uncalibrated Agilent 34401A. The short circuit current aren't much useful for absolute accuracy because in use there will be some portion of small current getting lost in the parallel resistor connected to the output, and I don't know at what input was it calibrated in factory. But it's useful to have some comparison across the channels. I also included another current measurement from the more accurate CH4 at 10 V, being loaded by CH1https://docs.google.com/spreadsheets/d/e/2PACX-1vSAmuvfcysmZyoXO-G8Ks2CuzfTUr3kWx1BcEYiueAI9lsqgBrvoLWwYOEaJRnOpns1F91hRUq4cZEK/pubhtml?gid=0&single=trueCH2 stability, the worse of the main two channels based on power supply readback range of vlaues. Still, it's regulated well within 1 mV (tested without load). 0.2 mV per division.CH3 stability, the rock solid aux channel, albeit limited only to 5.5 VCH4, the better aux channelNow for usability and user interface. In my opinion the front panel is well laid out, the controls are useful and easy to operate. For testing the supply when I need to change the output by small increments I use only the rotary encoder. It feels pretty good with noticeable but not too hard clicks. Unfortunately later I found that the resting position isn't so stable and there's small amount of play clockwise that can increment the value without moving to the next click. It doesn't happen often but sometimes I would find out that I dialed one more than I wanted. Otherwise I could count that each click was precisely one increment.Memory button is strangely used only to save or load all channel presets. There is screenshot function but burried in System-Setting-Hardcopy. However it doesn't work! Both saving channel values recording and the "Hardcopy" doesn't save anything to the USB stick. I tried both 4GB ones with same result. Even worse, the Hardcopy button freezes your supply, you can't even turn any channel off until you remove the stick. And that's with latest, couple months old 1.16 firmware. The only thing what I found works on the USB stick is saving and recalling the channel presets. Quite limited function if you ask me.Then there are more advanced functions of sequencing (for example you can make ramp up but you're very limited by 1 point-1change per second), delays, monitor alarms. You can also change the display style, there are 5 regular ones and two waveforms. But only the first one shows all 4 channels together with both set voltage and set current visible. If you don't need that or want to see only one channel at a time then it can be useful to have much larger font on the display. The look is quite pleasing, certainly better than average with good readability. Unfortunately the large LCD is also very reflective so at different angles you can see more what's on your desk or behind you rather than the power values. In darker corner it's not a problem.Another problem recessed jacks, by that I mean both the safety EU style plugs and the indented lower panel. If you look at it down you won't see any of those channel labels. I solved it by printing transparent label on the bottom. Closer examination reveals venting holes under the display/button bump, so that's perhaps the reason for that shape, still doesn't explain why GW Instek couldn't label the channels at the bottom. There's also no color coding which could be certainly useful to orient yourself in the unusual CH4-CH1-GND-CH2-CH3 arrangement.

author: jjoonathan
author_rank: Frequent Contributor
timestamp: March 29, 2021, 12:06:43 am
content: Did somebody say "no color coding"? My time to shine! On a GPP-4323, no less.

author: Markus2801A
author_rank: Regular Contributor
timestamp: July 10, 2021, 08:31:02 am
content: Helloare you still satisfied with the GPP-4323.Are there any annoying noises like transformer humming etc. coming from the unit?Thanks in advance!Kind regards and stay healthy!Markus

author: jjoonathan
author_rank: Frequent Contributor
timestamp: July 10, 2021, 12:52:57 pm
content: Yep, it still works just as well as it did on the first day. No hum, no egregious fan revving, it just works. I'd still recommend it.

author: Markus2801A
author_rank: Regular Contributor
timestamp: September 06, 2021, 09:29:58 am
content: Quote from: jjoonathan on July 10, 2021, 12:52:57 pmVery cool to hear that you are satisfied.In the meanwhile I got my unit too! It's indeed a very great device. Build quality is superior to the Owon Unit I had before (and returned it because of the annoying humm noise!).I really like it! Its Firmware is March 2021! v1.17 :-) seems to be brand new.Fan Noise is audible but its not annoying its relatively quiet :-)

author: Martin.M
author_rank: Frequent Contributor
timestamp: October 17, 2021, 03:12:05 pm
content: I have a question:is there a current offset ?

author: Electro Fan
author_rank: Super Contributor
timestamp: October 17, 2021, 04:27:39 pm
content: GPP-4323 ripple test (by jjoonathan, author of color coding video)https://youtu.be/UxEG-gMXnoQAnd review of GPP-4323https://youtu.be/SE7xzR4Q4mAEdit: I like this reviewIt makes a pretty good case for the product - Instek should consider jjoonathan‘s feedback on the product features and they should adopt/convey his rationale about the value proposition regarding the multiple PSs + the load function in their marketing

author: Hydron
author_rank: Super Contributor
timestamp: October 17, 2021, 06:21:14 pm
content: Yes, it does have a small but annoying offsets. While I like mine, I really wish GW Instek would share the calibration procedure so I could try and eliminate them. I've had a poke around in the firmware but am not experienced enough to work out how to access the calibration routine.

author: Electro Fan
author_rank: Super Contributor
timestamp: October 17, 2021, 07:35:26 pm
content: Quote from: Hydron on October 17, 2021, 06:21:14 pmKorad provides a front panel calibration procedure - has anyone asked GW Instek if they can provide one?

author: nctnico
author_rank: Super Contributor
timestamp: October 17, 2021, 07:52:31 pm
content: Given the small offset I strongly doubt you can make it any better. Just look at how small it is compared to the full range. IOW: don't mess with it; you'll likely make it worse.

author: julian1
author_rank: Frequent Contributor
timestamp: October 17, 2021, 08:23:28 pm
content: 32V/3A is quite a lot. Does it have a switching pre-regulator?

author: tautech
author_rank: Super Contributor
timestamp: October 17, 2021, 08:52:55 pm
content: Quote from: julian1 on October 17, 2021, 08:23:28 pmHardly, plenty of linear PSU's have such specs.

author: Martin.M
author_rank: Frequent Contributor
timestamp: October 17, 2021, 09:08:32 pm
content: set it to:12V 5mA to understand why the question for this small offsets is interestingWe have to add it to the setting. I have payed this 800€ to have a trustful current control in small areas.Otherwise any chinese PSU for 120,- can do the job also

author: mawyatt
author_rank: Super Contributor
timestamp: October 17, 2021, 09:57:11 pm
content: Quote from: Martin.M on October 17, 2021, 09:08:32 pmExactly!! Lots of folks that haven't worked in research labs with advanced SOTA semiconductors that are highly susceptible to damage by just slight over voltage or over current, don't appreciate having a precise voltage and current limit. Almost 50 years ago we lost well over $20K of chips because of a lab supply slight overshoot on start up, that's why I won't consider Korad (think a Rigol also had an overshoot issue), I'll let others play Russian RouletteI hosed up a SDP3303X-E by not following the calibration procedure and created a current offset that now I can't remove...all my faultWith this offset I'm reluctant to use this supply now for any precision work, since I know from experience it will come back and bite me sooner or later. Just now, I've got ~$3K of chips sitting on the other side of the supplies I'm using, so very careful with setting a reliable and accurate current limit, as well as voltage.The SDP3303X-E are good (after augmentation), and I can rely on a few ma for current limit if required, but suspect the GPPs are better.Wish someone would figure out how to remove this current offset on the one SDP3303X-E we have, the other 2 are fine. However, for now it's not going to see any serious use because of the offset.Best,

author: nctnico
author_rank: Super Contributor
timestamp: October 17, 2021, 10:27:11 pm
content: Quote from: mawyatt on October 17, 2021, 09:57:11 pmBut main thing is that wanting a few mA from a PSU which has a 3A range is too much to ask. You are working next to the noise level of the current sensing circuitry of a regular power supply in such a case. For these kind of jobs you need a PSU with dual current range (like the older Agilent 663xx series which still has a >1mA setpoint uncertainty) or an SMU.

author: mawyatt
author_rank: Super Contributor
timestamp: October 17, 2021, 10:46:33 pm
content: Quote from: nctnico on October 17, 2021, 10:27:11 pmAgree, the best case is using a supply with the proper current limit range, and Keysight and others higher end types have these. However, some of the mid price range supplies mentioned are quite good down in the ma range, know the SDP3303X-E when augmented and calibrated (please follow the Siglent cal routine) is OK. Did quite a bit of testing before I would consider using the SDP3303X-E for the development work we are currently involved with. Haven't used any of the GPP stuff you and others have, but from what you've posted and others this seems like superb equipmentOne thing about these newer medium cost range supplies, they seem to be utilizing the new Sigma-Delta ADCs and DACs chips which provide large dynamic ranges and likely why they can dive down into the ma range and still support 3 amps. These chips are remarkable considering the cost, and many are finding their way into mid range DMMs as well.Best,

author: 2N3055
author_rank: Super Contributor
timestamp: October 18, 2021, 12:01:47 am
content: Quote from: Martin.M on October 17, 2021, 09:08:32 pmIf you want really good control of 12V in region of 5mA NONE of the general purpose PSU are to be trusted. Even expensive Keysight or R&S.They all have output capacitors that will discharge significant energy in DUT if it suddenly starts to pull large current.Simply put, you set PSU for 12V and 10mA and connect small LED with PSU output enabled and you will kill the LED, unless it is one of those high power types..For instance, my Rigol DP831, outputs 4,9mA when set for 5mA and 12 V. Quite better than specs. But that holds only if you set current with outputs OFF, connect the load and then enable PSU outputs. This way output capacitors inside PSU (those soldered directly to output terminals) are discharged, and will actually contribute that output voltage will slowly ramp up until output current reaches 5 mA. For a red LED about 2 V. It will ramp up slowly because it will need to charge capacitors in addition to supplying current to DUT. But if you disconnect the load, capacitors will charge to full voltage and if you connect DUT again, it will discharge full voltage into DUT, without current limit. Current limit circuit is before output capacitors.On top of that, 5 mA on a 3 A is well in the error band on that GW Instek PSU that in datasheet has specified:Line Regulation ≦0.2%+3mALoad Regulation ≦0.2%+3mARipple & Noise ≦ 2mA RMS(let's say P-P on that would be 10mA)It is not clear whether 0,2% is from full scale or set value...Anyhow, you can have up to 6 mA offset and 2mA RMS fluctuations and your PSU would be in spec.IN addition to all mentioned, most of the general purpose PSU you can buy, despite having both voltage and current controls, are not very good at switching from CV to CC mode and back. They can have delays in reaction, in which output is not very controlled. These are milliseconds (or microseconds) but you can get spikes of overvoltage/overcurrent. You wouldn't see them on multimeter, but will see them on a scope.If you have to have control of 5mA at 12 volts, you have to have something called SMU (source measure unit) that will have fine control, or at least a precision power supply that is made for small currents ( smaller than 100 mA maybe) and have small output capacitor ( so it cannot discharge significant energy into DUT).Odds are it would be quite easier for you to make one that would be good for your purpose than find something to buy that won't cost an arm and a leg.I'm afraid that you bought device that is not what you expected. Not that it is not a good device, it is quite good general purpose PSU, but not what you though it would be.

author: nctnico
author_rank: Super Contributor
timestamp: October 18, 2021, 01:17:59 am
content: A side note: it is a good custom to set a PSU to a voltage which can't harm the DUT even when you are only interested in sending current through the DUT. The amount of energy in the output capacitors goes up exponentially with the voltage so the lower the output voltage, the less damage a discharge can do. Setting a PSU to 12V / 5mA to test an LED is not a good way of doing such a test. Look up the worst-case forward voltage first and set the PSU to a little bit above the worst case forward voltage.

author: mawyatt
author_rank: Super Contributor
timestamp: October 18, 2021, 01:41:12 am
content: This sorta gets into the grey area of what is safe regarding energy discharge. Eons ago when working with Rad-Hard designs I recall a spec that was 10mJ per supply line as the maximum available energy source for safe recovery from an event. The assumption was that all the energy would discharge into the forward biased chip to substrate junction caused by the nuclear event, if the chip was junction isolated.A little math shows the maximum capacitance as:C = 139uF for 12 voltsC = 800uF for 5 voltsC= 1837uF for 3.3 voltsEdit: Corrected above.Of course the 10mJ is from long ago, and one would expect modern chips to be more sensitive, how much more sensitive I don't know.The message 2N3055 coveys is important, you want the lowest possible output capacitance from your supply. The popular concept of loading the supply lines with lots of capacitance to reduce ripple effects may not be a wise choice!!Using a supply that misbehaves when entering or leaving CC is also a recipe for disaster, as is voltage overshoot on startup or shut down. The only supply I'll comment on is the ones we selected for the critical use in the on-going development project, which is the Siglent SDP3303X-E. These have been tested, augmented to 3303X and calibrated and behave well.All this reminds me that we are entering an area with the ongoing project where over $10,000 of chips could be instantly ruined by a mistake. We've taken measures in the power supply design to provide protection from reverse voltage, over voltage, excessive current and so on, but need to revisit the main bench power supplies and check them out very carefully. We've already put a new ODA HV Lab Type supply thru a loaded multi-day burn in outside. It had a horrid smell from the lacquer used to seal the two power transformers, so another good reason to burn in outsideBest,

author: nctnico
author_rank: Super Contributor
timestamp: October 18, 2021, 10:47:15 am
content: Quote from: mawyatt on October 18, 2021, 01:41:12 amGreat you like your Siglent PSU but don't think the GW Instek is anything less. Siglent probably learned everything there is to know about PSU design from GW Instek. They (Siglent and GW Instek) released at least one PSU which is 100% identical and GW Instek has been in test equipment business (first specialising in power supplies) a lot longer compared to Siglent.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: October 18, 2021, 03:44:10 pm
content: Siglent SDP3303X-E says you dont have short circuits on your 5v ( digital section ) anytime.Bad design, same with the Rigol.Edit : me happy GW fanboy.Just reading this topic :https://www.eevblog.com/forum/testgear/rigol-dp832-random-reboots/

author: mawyatt
author_rank: Super Contributor
timestamp: October 18, 2021, 04:11:33 pm
content: Quote from: nctnico on October 18, 2021, 10:47:15 amEarlier stated "Haven't used any of the GPP stuff you and others have, but from what you've posted and others this seems like superb equipment", the GPP was referring to GW Instek Power SuppliesBest,

author: Jan Audio
author_rank: Frequent Contributor
timestamp: October 18, 2021, 04:24:18 pm
content: You can still buy them.If china invades taiwan first thing they do is downgrade the GPP4323 to fixed amperes on the extra channels.

author: mawyatt
author_rank: Super Contributor
timestamp: October 18, 2021, 04:27:34 pm
content: Quote from: Jan Audio on October 18, 2021, 03:44:10 pmYes aware and we don't use the 5v section for any critical work, always for critical use the two variable voltage and current limit sections. We have 3 SDP3303X-E and they are good down to low voltage and currents as mentioned on those 2 outputs. One unfortunately isn't usable because of the current limit offset mentioned caused by my improper calibration, which makes for a risk for critical use and not acceptable to us.GW seems like a good alternative, we'll definitely be looking at those for any future power supply needs.BTW not a bad design by Siglent, they chose a simple linear regulator to keep within a cost budget....likely why the GW costs moreBest,

author: Jan Audio
author_rank: Frequent Contributor
timestamp: October 18, 2021, 04:31:21 pm
content: Well it cost not to much, Ｒ＆Ｓpricing are off the charts.Not much choise left.

author: mawyatt
author_rank: Super Contributor
timestamp: October 18, 2021, 04:32:17 pm
content: Quote from: Jan Audio on October 18, 2021, 04:24:18 pmNope, first thing they'll do is claim TSMC as a Chinese "asset" and "claim" China invented all the sub-micron semiconductor technologyBest,

author: mawyatt
author_rank: Super Contributor
timestamp: October 18, 2021, 04:35:37 pm
content: Quote from: Jan Audio on October 18, 2021, 04:31:21 pmGW price is reasonable.Like R&S, Keysight is very expensive tooBest,

author: Jan Audio
author_rank: Frequent Contributor
timestamp: October 18, 2021, 04:36:28 pm
content: By the way 2 of that other brand are more expensive then.

author: DeadlyErnest
author_rank: Newbie
timestamp: May 31, 2023, 01:09:29 am
content: Quote from: mawyatt on October 18, 2021, 04:27:34 pmSiglent 3303C has current limiting on 3rd 5/3.3/2.5 volt output.

author: nctnico
author_rank: Super Contributor
timestamp: May 31, 2023, 03:35:01 pm
content: Quote from: DeadlyErnest on May 31, 2023, 01:09:29 amBut not adjustable! And that is precisely the point... Without adjustable current limiting, the extra output is a gimmick with very little practical use.