From Wikipedia, the free encyclopedia Powered USB
Powered USB
This article is about the proprietary variant USB As each Powered USB plug provides one of three volt-
standard. Self-powered conventional USB devices may ages, the plugs come keyed in three versions so they will
also colloquially be referred to as "powered USB"; cf. e.g. only accept connections from devices requiring that ver-
self-powered USB hubs. sion’s voltage.[2]
Extending USB’s power capability is a response to
Power over Ethernet which has more flexible dynamic
power negotiation capabilities up above 48 V DC and up
to about one amp, and whose maximum bandwidth is po-
tentially greater than USB 3.0’s once the 10 Gbit/s Eth-
ernet standard is supported. The combination of USB 3.0
and a 6 A limit at the most common (5, 12, 24 V DC) volt-
ages permits support of a wider variety of devices, al-
though powered Ethernet can support them at longer ca-
ble distances, power loss in small DC voltages are very
significant over even a few meters, so it is unlikely that
powered USB can compete over longer distances effec-
tively.
12 V and 24 V powered USB sockets, on an NCR cash register References
[1] What is Powered USB?
USB,
Powered USB also known as Retail USB, USB Plus Pow-
[2] ^ Powered USB in Retail
er, and USB + Power, is an addition to the Universal Serial
[3] U.S. Patent 6,086,430
Bus standard that allows for higher-power devices to ob-
[4] U.S. Patent 6,334,793
tain power through their USB host instead of requiring
[5] "PoweredUSB - FAQs and Answers".
an independent power supply or external AC adapter. It
http://www.poweredusb.org/faqs.html. 070727
is mostly used in point-of-sale equipment, such as receipt
poweredusb.org
printers and barcode readers.
[6] Powered USB Electro-Mechanical Specification
Powered USB, as a proprietary variant of USB, was de-
v0.8g
veloped by IBM, NCR, and FCI/Berg but is not endorsed
[7] SuperSpeed USB 3.0 FAQ
by the USB Implementers Forum (USB-IF).[1][2] IBM, who
owns the patents to Powered USB,[3][4] charges a licens-
ing fee for its use.[5] External links
Powered USB uses a more complex connector than • http://www.poweredusb.org — An informational
standard USB, maintaining the standard USB interface website
for data communications and adding a second connector
for power. Physically, it is essentially two connectors
stacked such that the bottom connector accepts a stan-
dard USB plug and the top connector takes a power plug.
The implementation allows a choice of three differ-
ent voltages, providing power at 5 V (30 W), 12 V (72 W),
or 24 V (144 W). The three voltages are able to operate
at up to 6 A. USB 1.0 and 2.0 supplies 5 V at up to 0.5 A
(2.5 W).[6] USB 3.0 supplies 5 V at up to 0.9 A (4.5 W).[7]
Retrieved from "http://en.wikipedia.org/w/index.php?title=Powered_USB&oldid=462598548"
Categories:
• Power supplies
• USB
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From Wikipedia, the free encyclopedia Powered USB
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