Again in August 2021, I did a teardown of an Ubiquiti Networks power-over-Ethernet (PoE) injector, following up on the dissection of a TRENDnet PoE-supportive powerline networking adapter set from three years earlier. I did detailed PoE expertise overviews in each of these, which I’m not going to considerably replicate right here within the curiosity of brevity. Suffice it to say that:
- There are a number of variants of PoE expertise, some multiplexing DC voltage on the identical wires that carry AC knowledge transitions and others (particularly for 10/100 Mbps Ethernet) leveraging otherwise-unused wires-and-pins for DC transmission. i.e.:
The means by which energy is carried inside a ten/100 Mbps Ethernet cable additionally varies: with so-called “Mode A,” the ability supply takes place over the identical 1-2 and 3-6 pairs used for knowledge, whereas “Mode B” makes use of “spare” pairs 4-5 and 7-8. With Gigabit Ethernet, which employs all 4 pairs of wires for knowledge, merging knowledge and DC energy over the identical wires is the one possibility.
- Even inside a selected PoE implementation “taste” a range of enter (at supply)-and-output (at “sink”) voltage mixtures exist within the market, making multi-vendor and (even inside a standard provider’s product line) multi-product interoperability troublesome at greatest and extra possible a non-starter.
In case your PoE injector (or PoE support-inclusive router or change supply gadget, for that matter) implements one mode and your PoE splitter (or PoE support-inclusive distant gadget) implements one other, your solely recourse is a irritating return of 1 or each gadgets to your retailer. Voltage and present incompatibilities between supply and vacation spot may also end in a product return (to not point out, probably “fried” gear).
And concerning community topology node naming, excerpting from that premiere 2018 writeup:
If energy is added to the community connection at a PoE-cognizant router, change, or adapter supply, that exact energy sourcing gear (PSE) variant is known as an endspan or endpoint. In any other case, if energy is added in-between the router/change and distant shopper, resembling by way of an appropriately named PoE injector, that gadget is named a midspan. A PoE-cognizant distant shopper is known as a powered gadget (PD); a PoE splitter can alternatively present separate energy and knowledge connections to a non-PoE-supportive LAN shopper.
For extra background particulars, please see the sooner powerline-plus-PoE adapter and PoE injector writeups.
What we’re right this moment is one other PoE injector, the TP-DCDC-2USB-48 from Tycon Techniques:
Right here’s the sticker on the baggie my unit got here in (absent the USB cables proven within the earlier inventory photographs):
Why the seeming teardown-device redundancy? A part of the reply comes from the respective product names. The Ubiquiti Networks injector was particularly the mannequin 24-24W-G-US:
As I’ve discovered is often the case with PoE merchandise, the output voltage (for an injector, or alternately the enter voltage for a splitter) is embedded throughout the product title. Particularly, within the Ubiquiti Networks 24-24W-G-US case:
Right here’s the “decoder ring” for the product title: The primary “24” signifies that it outputs 24 V over the Ethernet connection; the next “24W” means what it says—24 W, alternatively indicating that the unit outputs 1 A max present; “G” implies that it helps GbE connections; and “US” implies that the ability wire has a US-compatible NEMA 5-15 wall outlet connection.
Notice, too, that since this gadget helps GbE (whether or not it truly delivers GbE over powerline is a completely different matter), “With Gigabit Ethernet, which employs all 4 pairs of wires for knowledge, merging knowledge and DC energy over the identical wires is the one possibility” applies.
If I apply a “decoder ring” to the Tycon Techniques TP-DCDC-2USB-48, conversely, what do I get? Actually, skimming by the corporate’ injector (which it additionally refers to in varied locations as “inserter”) product line net pages, I can’t discern an apparent sample. And in contrast to with Ubiquiti Networks, there isn’t express documentation to help me with the code decipher.
That stated, the “DCDC” portion may imply that we’ve an injector that not solely outputs DC voltage but in addition inputs it (versus, say, an injector with an built-in AC-to-DC energy provide, which might conceivably be an “ACDC” variant). Particularly, as you might have already observed from the inventory photographs, it takes its enter voltage from the twin 5V 1.4A (every) USB-A connectors on one aspect, presumably explaining the “2USB” portion of the product title. And, in contrast to the 24V/24W (1A)-output Ubiquiti Networks gadget, this Tycon Techniques one outputs 48V (at 12W, subsequently 0.25A) DC, subsequently—duh—the “48” within the title. However that all stated, each the Ubiquiti Networks and Tycon Techniques gadgets are passive, not energetic, that means that they supply a hard and fast output voltage; there isn’t a upfront negotiation as to what the powered gadget on the opposite finish of the Ethernet strand wants.
As one other key rationale for revisiting the “PoE injector teardown” theme, I’ll in-advance share with you one of many product photographs, that of the underside (as typical accompanied by a 0.75″/19.1 mm diameter U.S. penny for measurement comparability functions):
Once more, recall that the Ubiquiti Networks gadget was GbE-cognizant, subsequently utilizing all eight Ethernet wires for knowledge, so DC voltage multiplexing was a necessity. The even earlier analyzed TRENDnet PoE-supportive powerline networking setup wasn’t GbE-capable, even in principle, so it theoretically had 4 spare wires out there for DC voltage functions (presumably generated by an AC/DC converter contained in the adapter). However, it additionally was a multiplexed data-and-DC gadget, on this case the sooner mentioned 10/100 Mbit Ethernet “Mode A”. In distinction, from the photograph you’ll be aware that this gadget is “Mode B”, finishing the implementation possibility selection.
The ultimate notable revisit rationale was basically curiosity-fueled. I’d discovered the Tycon Techniques TP-DCDC-2USB-48 on the market used at Lensrentals, a photograph (largely video) gear retailer that I’ve talked about (and purchased stuff from a number of occasions) earlier than. The gadget’s listed worth was solely $22; on the time (November 2023) a further 15%-off promotion made it even extra economical ($18.70 plus tax). However what on earth was a PoE injector doing on the market at a photograph gear retailer’s web site? This remaining TP-DCDC-2USB-48 inventory photograph supplies a clue:
Much more telling, after a bit of unveiling analysis, is the seemingly cryptic “VR – Orah PoE Injector” notation on the Lensrental web site product web page for the Tycon Techniques TP-DCDC-2USB-48. It refers back to the Orah 4i, a four-fisheye-camera plus multi-mic setup for live-streaming 360° spherical digital actuality:
The A/V seize module tethers to an Intel- and NVIDIA-based mini-PC “field” that stitches collectively the assorted sources’ A/V knowledge earlier than community broadcasting the consequence. And talking of networks—particularly, Ethernet cables—a few of you could have most likely already guessed how the mini-PC and cameras-plus-mics module linked…over PoE-augmented Ethernet, by way of the injector on the “stitching field” aspect and instantly powering the seize module on the opposite finish.
1,000 (hopefully instructional) phrases in, let’s get to ripping down, lets? You’ve already seen my gadget’s underside; listed below are views from different views. High-side block diagram first; gotta love that “Ethent” spelling variant of “Ethernet”, eh?
The 2 naked sides:
The enter voltage-and-data finish:
And the unified voltage-plus-data output finish:
The seam alongside all 4 sides wasn’t glued down, however one thing else was nonetheless holding the 2 halves collectively:
I discovered it after I peeled away the underside sticker:
That’s higher:
Notice the sizeable floor aircraft and different thick traces on the PCB underside, much like these encountered with the Ubiquiti Networks PoE injector three years again:
The PCB pops proper out of the highest with no further screws to be eliminated first:
On the far proper is the ability LED, with the Ethernet connector above it and the twin USB energy inputs under. Two inductors alongside the underside, one among them toroidal. The PoE connector is on the left edge. Two extra inductors within the higher left nook (one once more toroidal), with two capacitors in-between them. On the prime is a Linear Expertise (now Analog Units) LT1619 low voltage present mode PWM controller for DC/DC conversion functions.
And what of that warmth sink to the appropriate of the PoE connector? Glad you requested:
It’s usually held in place by glue (to the PoE connector) to at least one aspect and a thermal pad beneath. And under it are two ICs: an On Semiconductor FDS86140 small sign MOSFET and, to at least one aspect (and subsequently solely partially connected to the thermal pad) a chip marked:
CSP
10S100S
citc
and a “D1” mark on the PCB alongside, which I’m guessing is a 3-lead Schottky diode (readers?).
In conclusion, listed below are some PCB side-view pictures on your perusal:
That’s what I’ve bought for right this moment. I’m now going to attempt to meaningfully reattach the warmth sink and in any other case return the TP-DCDC-2USB-48 to full performance. Why? The spec sheet says it greatest:
This USB powered PoE injector is a should for any technician’s toolbox as a result of it permits powering …Passive PoE merchandise from a laptop computer’s USB port. The 48VDC passive PoE mannequin is ideal for powering IP Telephones, Cameras and different gadgets that use 48VDC PoE. This permits the technician to shortly check the gadget by direct connection to his laptop computer, saving him quite a lot of time. The TP-DCDC-2USB-xx will also be utilized in buyer premise gear to energy exterior wi-fi gear from a buyer’s laptop USB ports, lowering wiring litter on the PC and permitting the wi-fi gear to be powered down when the pc is powered all the way down to preserve power.
As at all times, I welcome reader ideas within the feedback!
—Brian Dipert is the Editor-in-Chief of the Edge AI and Imaginative and prescient Alliance, and a Senior Analyst at BDTI and Editor-in-Chief of InsideDSP, the corporate’s on-line publication.
Associated Content material
- Teardown of Ubiquiti’s 24-24W-G: A PoE adapter with out (a) peer
- Teardown: Powerline networking plus PoE
- Will PoE++ be useful, a headache, or each?
- Easy circuit design tutorial for PoE purposes
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