Mains PSU in IEC mains filter case - Page 1
Forum section: electronics / general

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 04, 2019, 10:40:52 pm
content: Very neat idea - Small PSU built into an IEC manis filter case.https://www.digikey.com/en/blog/complete-5-watt-power-supply-in-iec-main-filter-case?utm_source=twitter&utm_medium=social&utm_campaign=blgcmplte5wattpwrsupMight cause some interesting results if, down the line, someone decides to replace a faulty one with a mains filter they had to hand...

author: stevelup
author_rank: Regular Contributor
timestamp: March 04, 2019, 10:48:55 pm
content: Very neat solution.

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 04, 2019, 11:18:39 pm
content: Isn't that basically one of those compact smartphone chargers repackaged into a different case?

author: Bratster
author_rank: Frequent Contributor
timestamp: March 05, 2019, 12:57:39 am
content: That is pretty slickSent from my Fi Moto x4 using Tapatalk

author: wraper
author_rank: Unknown
timestamp: March 05, 2019, 01:05:54 am
content: Quote from: mikeselectricstuff on March 04, 2019, 10:40:52 pmYeah, and using 6.3 mm faston connectors as regular filters just asks for that. I wonder why would them use them for <1.5A output current.

author: amyk
author_rank: Super Contributor
timestamp: March 05, 2019, 01:41:14 am
content: Seeing that form factor brings back memories... bad memories:https://www.eevblog.com/forum/repair/hp3458a-schaffner-mains-line-filter-failure/

author: TERRA Operative
author_rank: Super Contributor
timestamp: March 05, 2019, 07:49:24 am
content: Oh, this is a nice part. I have a use for this in a current project that will simplify things quite a bit...

author: Jeroen3
author_rank: Super Contributor
timestamp: March 05, 2019, 08:32:00 am
content: Kettle connector? I have never seen this connector on a kettle. Kettles are always have a fixed 1M 3G1.5mm2 wire..Anyway, Recom is one of those companies that makes nice stuff for an affordable price. This plug is great.

author: rdl
author_rank: Super Contributor
timestamp: March 05, 2019, 08:35:35 am
content: That's not a bad idea. I have to admit being a little ambivalent about it though. Basically it moves the wall wart inside the device at the expense of a larger, bulkier power cord.

author: Psi
author_rank: Super Contributor
timestamp: March 05, 2019, 08:47:05 am
content: That is super cool.I do see a big safety issue though.Sooner or later someone is going to copy a photo/diagram they see online and use a ICE plug that doesn't have a 5V psu inside.Or someone will try to repair a device by replacing the IEC and will assume it's a normal 230v filter socket.

author: BradC
author_rank: Super Contributor
timestamp: March 05, 2019, 09:12:23 am
content: Quote from: Psi on March 05, 2019, 08:47:05 amI don't see an issue. They'll only do it once.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 05, 2019, 09:21:28 am
content: Quote from: wraper on March 05, 2019, 01:05:54 amI think they should have used a different connector, maybe a 3-pin JST VH

author: H.O
author_rank: Frequent Contributor
timestamp: March 05, 2019, 11:10:08 am
content: Stumbled across this one a week ago when I was looking for a small 24VDC supply for a project and immediately ordered one.Very neat indeed but yeah, it's notentirelywithout risks.

author: TimNJ
author_rank: Super Contributor
timestamp: March 05, 2019, 07:22:39 pm
content: Saw this the other day too. I might buy one and tear it down to see if there's anything special/neat about it internally (probably not!).Regarding it being dangerous, I'm on the fence. You are very unlikely to mechanically damage the IEC inlet from use, and thus it's probably unlikely it will ever need to be replaced for that reason. If the internal SMPS fails, and it needs to be replaced, then of course there is a potential safety issue. (That said, I think the probability is fairly low that the power supply fails AND that the user will actually try to replace it.)Looks like they had tooling available for a standard IEC filter can, and just went with it.

author: TERRA Operative
author_rank: Super Contributor
timestamp: April 01, 2019, 12:01:08 pm
content: Well, I got my hands on one for a small project, so I thought I'd take a quick look at it.Seems it can kick out a bit more current than the data sheet says for at least a short period of time.https://youtu.be/_qdTVKohC-o

author: nctnico
author_rank: Super Contributor
timestamp: April 01, 2019, 03:46:28 pm
content: I just spotted this. Looks neat but I agree on the 6.3mm fastons being a bad idea. No PCB mount version?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: April 01, 2019, 05:05:00 pm
content: Quote from: nctnico on April 01, 2019, 03:46:28 pmNot sure PCB mount would be particularly useful due to mechanical issues, but I'd have liked to see a JST VH connector, or flying leads instead of the tabs.

author: TERRA Operative
author_rank: Super Contributor
timestamp: April 01, 2019, 10:47:59 pm
content: Yeah, I agree. I suspect they just used a pre-existing housing from a standard filter to save costs.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 01, 2019, 11:03:46 pm
content: How long before someone has the idea to make a simple chassis mount adapter that has an IEC socket on the outside and a mains socket on the inside, so that any wall wart can be turned into an internal PSU? Actually, that can be as simple as using an IEC to mains socket pigtail with a plastic frame to hold it into the chassis - 3D printed for small runs and injection molded for high volume production.

author: Zero999
author_rank: Super Contributor
timestamp: April 02, 2019, 04:58:19 pm
content: Quote from: NiHaoMike on April 01, 2019, 11:03:46 pmI've done that before, with a PSU with a two pole mains connector. I drilled holes in the case for the connector and fixed it to the inside, with a metal bracket and rubber foam padding. It worked quite well, but there's no point in doing it in a commercial product: it's much easier and cheaper to have the PSU separate and use a connector. I only did it because I didn't want someone losing/stealing the power supply. That reminds me, I should put a double insulated symbol on it, before one of the goons from the electrical department quarantines it because it has a metal case and isn't earthed.

author: Nauris
author_rank: Regular Contributor
timestamp: April 03, 2019, 04:49:10 pm
content: It also has earth connection, that is usually missing in normal wall warts! No more worries from leakage currents.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: April 03, 2019, 05:20:27 pm
content: Quote from: Nauris on April 03, 2019, 04:49:10 pmThe earth is not connected to the PSU itself (not needed for filtering on a low-power PSU), but is avaiable for user connection

author: TERRA Operative
author_rank: Super Contributor
timestamp: June 27, 2019, 12:16:15 am
content: Thread bump...I got some photos sent to me by the guy who designed these things, they look pretty good inside.https://youtu.be/jMjbOB2dH40

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 27, 2019, 12:48:58 am
content: Cool!Looks like a TNY174 or something like that; these are a hysteretic controller so beware of output ripple, and modest efficiency (but these are small supplies, who cares).The Y cap looks to be quite large (probably 4.7n) so the leakage comment isn't quite correct. I think I would still want to use this with a common mode choke and filter cap (and LDO if low ripple is also needed) on the output side, just in case. There aren't many options for dealing with EMI otherwise, since it's right on the mains.Would guess they're useless for higher energy or more repetitive surge ratings, too; that's simply a case of knowing the rating and selecting products appropriately.Tim

author: Red Squirrel
author_rank: Super Contributor
timestamp: June 27, 2019, 01:49:03 am
content: Those really are neat, and decently priced. $16, and they go up to 24v (looking at Digikey's offerings at least). This would be mostly for low power stuff but I'm sure it has it's niche applications.

author: Nauris
author_rank: Regular Contributor
timestamp: June 27, 2019, 05:28:09 pm
content: Quote from: T3sl4co1l on June 27, 2019, 12:48:58 amBut it has earth pin, you can do a trick and tie that with output and da-daa all leakage gone! Can't do that with ordinary wallwarts. It seems like earthed small <10 W wallwarts just don't exist and I have looked thru many catalogs. This is the first one I have heard of.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 27, 2019, 10:43:15 pm
content: Sort of. If you ground the output, it's not exactly isolated anymore! Also the mains leakage is then set by the 4.7n, which can be a lot for certain applications (namely, medical).Tim