On Mon, Jan 5, 2015 at 4:54 PM, Ingo Korb <firstname.lastname@example.org> wrote: > Marko MÃ¤kelÃ¤ <email@example.com> writes: > > (powering an HDMI source from the sink) > > > Oh, I see. However, let me quote a comment on > > > http://www.androidauthority.com/chromecast-dongle-official-specs-features-release-date-pricing-248120/ > > "A reviewer on Amazon who apparently already has the device (developer I > > think) says that the device can be powered directly off an HDMI v1.4 > > connector without using the USB power brick. > > I suspect that is a fluke caused by an HDMI sink that applies power to > the 5V pin even though it should not. When powered from USB the > Chromecast draws about 300mA with peaks up to 400mA, so it's waaaay > beyond the 55mA you officially get anyway. > > I'm not really surprised though - there are also quite a few USB hubs > out there that try to power the computer from their own 5V power brick > even though that is also the wrong direction. > I wound up with a USB hub that did exactly this. It had a 9VDC unregulated brick, no internal regulator, and feedback to the PC. It fed everything 9 volts. Good thing I look inside things before I trust them! PS: don't trust cheap multiport hubs ;) In the end it's just another case of "don't expect it to work but be > happy if it does" as well as "be suspicious of the other guy and try to > make sure that he can't kill you". ;) > > > See http://www.hdmi.org/learningcenter/kb.aspx?c=13 for more info > > about HDMI accessory power requirements." > > > > The linked FAQ page says that HDMI-powered devices should offer a > > fallback of an alternative power supply. > > Yes, but the wording of that FAQ entry seems to suggest to me that it is > meant only for HDMI sinks that are powered by a source device. > > -ik > > Message was sent through the cbm-hackers mailing list > Message was sent through the cbm-hackers mailing listReceived on 2015-01-05 23:00:03
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