RJ45/PoE DC-DC to Barrel

[Idea]

I'm curious is anyone has seen an integrated solution that takes passive 24V PoE and converts it to other common voltages, for instance some common adapters like 5V 1.5A or 12V 1A?

In my mind it could be an RJ45 connector on one end and a simple barrel jack on the other, or in the case of 5V it could be USB A. I'm aware that I can use normal PoE breakouts into a regulator but I'm curious if anyone has seen anything like this as an integrated unit.

This nice thing about using PoE rather than just tapping the regulator is that you can use the switches power measurement and control facilities. For instance I have an upstream provider that uses old 100BaseFX to 10/100TX that run on 5V 1.1A. Their procedure for identifying their side of the link involves disconnecting and reconnecting the power supply. It's nice to be able to do it without having to go to our site.

[Idea]

TP-Link has these:
http://www.tp-link.com/us/products/deta ... ifications but they're 802.3af

[jakematic]

These have been quite reliable for me - and have a variety of connector pigtails.
If you chose 12/24V PoE they work perfectly with passive, and at $12 are 1/2 the price of the 802.3af ones.

They provide 5V 10W output - have several running Raspberry Pi's connected to my Netonix... Netonixes ? .... Netonixii ?
Edit: There's also a 12V 1A version

https://find-a-poe.com/product/PoE-for- ... E-Devices/

[Idea]

Thanks! I'll give those a try

[Idea]

These ended up being a bit of a no-go. If I leave the load plugged in and then cycle PoE then the whole adapter shuts down. If I leave PoE plugged and then remove the load the unit turns on and stays on even after the load is reapplied. Unfortunately that means the 5V gear doesn't come up automatically after a PoE power cycle or failure.

My guess is that it's a problem with short circuit detection although the load is less than 1.8A. I opened the case and noticed there's a capacitor that's been (presumably purposefully) bodged off. I have two units and its the same in both. Doesn't inspire confidence.

[jakematic]

If I leave the load plugged in and then cycle PoE then the whole adapter shuts down. If I leave PoE plugged and then remove the load the unit turns on and stays on even after the load is reapplied. Unfortunately that means the 5V gear doesn't come up automatically after a PoE power cycle or failure.

Not sure I understand...

Just tested with an RPI and it worked exactly as I would expect - just as though I ripped the power out from under it:

Code: Select all

Mar 12 08:51:49 ws8b.jakematic.lan UI: Port 7 bounced by admin (192.168.0.141)
Mar 12 08:51:49 ws8b.jakematic.lan Port: link state changed to 'down' on port 7
Mar 12 08:51:49 ws8b.jakematic.lan STP: set port 7 to discarding
Mar 12 08:52:06 ws8b.jakematic.lan Port: link state changed to 'up' (100M-F) on port 7
Mar 12 08:52:06 ws8b.jakematic.lan STP: set port 7 to discarding
Mar 12 08:52:09 ws8b.jakematic.lan STP: set port 7 to learning
Mar 12 08:52:09 ws8b.jakematic.lan STP: set port 7 to forwarding
Mar 12 08:52:10 ws8b.jakematic.lan Port: link state changed to 'down' on port 7
Mar 12 08:52:10 ws8b.jakematic.lan STP: set port 7 to discarding
Mar 12 08:52:12 ws8b.jakematic.lan Port: link state changed to 'up' (100M-F) on port 7
Mar 12 08:52:12 ws8b.jakematic.lan STP: set port 7 to discarding
Mar 12 08:52:14 ws8b.jakematic.lan STP: set port 7 to learning
Mar 12 08:52:14 ws8b.jakematic.lan STP: set port 7 to forwarding


Had one on the bench this week and left the ethernet plugged in with PoE active and removed the power pigtail - also worked as expected.

[lligetfa]

My guess is that it's a problem with short circuit detection although the load is less than 1.8A...

1.8A on the 5V side or the 50V side? If on the 5V side that is only 9W but if on the 50V side that is 90W and sure to smoke the port!

[jakematic]

1.8A on the 5V side or the 50V side? If on the 5V side that is only 9W but if on the 50V side that is 90W and sure to smoke the port!

Must be on the 5V side..


Out of curiosity I powered a dongle up with nothing attached, and it shows 0 watts.
So the device itself does not have a draw until there is something connected.

Code: Select all

Mar 13 11:02:54 ws12.jakematic.lan UI: Configuration changed by admin (192.168.0.141)
Mar 13 11:02:54 ws12.jakematic.lan UI: Port 5 PoE: changed from 'Off' to '24V'
Mar 13 11:02:57 ws12.jakematic.lan switch[1359]: PoE enabled on port 5, PoE Smart is starting cable check
Mar 13 11:03:02 ws12.jakematic.lan switch[1359]: Port 5 cable check results: Open, Open, Open, Open
Mar 13 11:03:02 ws12.jakematic.lan switch[1359]: Port 5 passed PoE Smart cable check, turning on power
Mar 13 11:05:12 ws12.jakematic.lan UI: Configuration changed by admin (192.168.0.141)
Mar 13 11:05:12 ws12.jakematic.lan UI: Port 5 PoE: changed from '24V' to 'Off'


This is the device I'm using: https://find-a-poe.com/product/PoE-for- ... %28Male%29