Low noise small PSU with 1mV/1mA resolution - Page 1
Forum section: electronics / testgear

author: BBBbbb
author_rank: Unknown
timestamp: June 23, 2021, 09:13:17 pm
content: Haven't been following the talk on the forum lately (life, job...) so I apologize if there have been some recent talks on this topic.I have a need for a low noise power supply, preferred resolution of 1mV/1mA, that has a fairly small footprint.No need to go above 5V, but low noise is an imperative, since I want to be confident when testing at near POR voltages.As far as I know uSupply died (was promising), and there are some IOT power profilers that still need an external PSU. With these devices I'm not sure how much noise propagates if the external supply is switching...Battery simulation would be a big plus, but that skyrockets the price and usually has a bigger footprint. High res. logging is a plus as well, but not as much...If you have any good suggestions they're welcomed here. Not sure I have a certain price point in mind, because I'm a sucker for "...but if you just add $100 you get this feature...", so I need to analyze what I can get at each price point... but not sure I'd go above something like 600-700usd, no matter what fancy features it has...

author: tautech
author_rank: Super Contributor
timestamp: June 23, 2021, 11:12:48 pm
content: One of the SPD1000X PSU's would meet your needs:https://www.siglenteu.com/power-supplies/spd1000x-series-programmable-dc-power-supply/

author: BBBbbb
author_rank: Unknown
timestamp: June 25, 2021, 10:46:34 am
content: Quote from: tautech on June 23, 2021, 11:12:48 pmOne thing a person can always count on is your Sigilent recommendation.Unfortunately I'm looking for something more portable than standard bench PSU (that I already have, and there's no way I'm carrying it around)There was some momentum 1-2yrs ago (at least I got that impression) with those little IOT power loggers/profilers, and I was thinking if something portable precise for low power is out there. uCurrent was maybe a solution...My needs are very limited, 5V max, and lets say max 200mA (for devices usually powered by a CR2032 or something in that range)Seems I'll just have to wait and see if such niche small precise PSU surfaces.For the time being last evening I pulled a trigger on MDP-P905. If I power it with a battery pack result should be good enough for most of my needs.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 25, 2021, 10:59:52 am
content: Have a look at:https://html.duckduckgo.com/html?q=MDP-XP

author: BBBbbb
author_rank: Unknown
timestamp: June 25, 2021, 11:06:20 am
content: Quote from: Doctorandus_P on June 25, 2021, 10:59:52 amExactly what I bought last evening (MDP-P905), but without the LCD/wireless addon that doesn't look useful.Miniware seems to have given up on the project, which is a shame. If powered from some batteries (still thinking if going with some 18650 or some eneloop-ish) this could give a pretty clean output in my range, based on MarcoReps review.Not all I was hoping for to find, but will do the job and if a mistake, not an expensive one (paid 120USD). Now I have to wait for it...

author: Skashkash
author_rank: Regular Contributor
timestamp: June 25, 2021, 11:21:47 am
content: 200ma current? 5volts?Maybe one of these?https://www.analog.com/en/design-center/evaluation-hardware-and-software/evaluation-boards-kits/adalm1000.html#eb-overviewBut it's not a standalone supply.

author: BBBbbb
author_rank: Unknown
timestamp: June 25, 2021, 11:55:33 am
content: Quote from: Skashkash on June 25, 2021, 11:21:47 amPC controlled is quite acceptable (even great that's programmable). Looks quite nice, but I don't know what ripple/noise peaks to expect, especially since powered through PC.Doubt it can come close to the MDP-P905 powered by batteries.The thing is I need it reliable when working with near brown out voltages. These are small communication devices (RF, BLE, UWB...), powered by a single coin cell most of the time, some fortified with (super)caps for the Tx bursts. I'm on the SW side of it, and most of the use for this would be when I'm checking the battery algorithm on my end, or some low power scenarios, and 10-20mV variations can screw with me a lot.

author: kwass
author_rank: Frequent Contributor
timestamp: June 25, 2021, 12:04:01 pm
content: Possibly too big/expensive, but I really like my BK1739https://www.testequipmentdepot.com/bk-precision/pdf/1739_datasheet.pdffor low noise/low power work. Also has current resolution to 0.1mA and no cooling fan!

author: Skashkash
author_rank: Regular Contributor
timestamp: June 25, 2021, 12:48:24 pm
content: Quote from: BBBbbb on June 25, 2021, 11:55:33 amCan't find the noise specs on the adalm1000, but schematics and circuit description are available.https://wiki.analog.com/university/tools/m1k/hwThey go to quite some lengths to mitigate usb noise.I've been using one to simulate a small lipo battery for an embedded low power application.Works well, but the software could be a little better.I'll try to throw the output of it into my new dmm6500 and see if I can get some noise figures under load.UPDATE:I hooked up an adalm1000 to my dmm6500 and did a couple of quick testsprogrammed the adalm100 for 3.0V outputmeasures at the DMM2.9998 no load2.9982 into a 60ma load (50 ohm resistor)90uv PP avg over 10k readingsDid not do any current measurements

author: BBBbbb
author_rank: Unknown
timestamp: June 25, 2021, 01:00:55 pm
content: Quote from: kwass on June 25, 2021, 12:04:01 pmYup, at 4kg gets too big.Last year when corona hit initially and full lockdowns were in place almost everywhere, I was stationary at home most of the time (very limited office access) and I wanted to upgrade my PSU (korad repack) to DP832, but the lead times were quoted by the distributor as - "I have no idea when it would come, I ordered some stock, normally takes 6 weeks but now god knows.."In the mean time I have access to my office again and good tools, but I'd like to be flexible and mobile as much as possible, so I'm looking at having a highly mobile dev environment.I was hoping that some type of portable precise PSUs focusing on IoT were popping up in the market (with limits in term of power that come with that type of portability)...

author: tautech
author_rank: Super Contributor
timestamp: June 25, 2021, 07:32:49 pm
content: Quote from: BBBbbb on June 25, 2021, 10:46:34 amOnly too happy to try and help.QuoteYou did say low noise was paramount hence the suggestion of a the single channel PSU's however your requirement for small in the OP is relative when it seems your really need something highly portable.QuoteSmall normally implies SMPS and low noise these are not and as you later add working at brownout levels you certainly will need something very clean.Happy hunting.