Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
all about USB3 power on a USB2 device?
I have been searching diligently an have not found the answer.
Will a USB3 port supply USB3 power to a USB2 device.
Obviously, it doesn't matter if the cable is USB3 or USB2 since the device will only connect to the USB2 pins. Also obviously the USB2 device won't operate at USB3 speed.
I just want to know if the power supplied on the USB2 pins via a USB3 port is to the USB3 spec.?
or... if I plug a USB3 device in with a USB2 cable will it be provided with USB3 power -- since it is only connecting to the USB2 power pin?????????
Apparently, a USB3 device connects to both the USB2 and USB3 power pins.
I can't believe I can't find this answer. And please refer me to something I can read on this - I don't want opinions - just the facts.
thx
NO BEST ANSWER - try reading the question - I guess no one knows................
4 Answers
- ?Lv 79 years agoFavorite Answer
If you connect a USB 2 external device to a USB3 port, the transfer will only be the same as USB2.
My understanding is that a USB3 plug is different to that of a USB2, but a USB2 will fit the port but reverts back to USB2 speed and transfer rates.
To get USB3 speeds, you'll need to connect a USB3 device with a USB3 cable to a USB3 port.
- Sasha WhitefurLv 79 years ago
"The USB 1.x and 2.0 specifications provide a 5 V supply on a single wire from which connected USB devices may draw power. The specification provides for no more than 5.25 V and no less than 4.75 V (5 V±5%) between the positive and negative bus power lines. For USB 3.0, the voltage supplied by low-powered hub ports is 4.45–5.25 V"
http://en.wikipedia.org/wiki/USB
Same voltage.
- Anonymous9 years ago
I think you are asking whether a USB 2.0 device connected to a USB 3.0 port will receive power at USB 3.0 speeds. Unfortunately, this is not the case.
A USB 2.0 device is not built to receive power at that rate. For example, an iPhone will not receive power at USB 3.0 speed when plugged into a USB 3.0 port.
However, many users will say that if you plug a USB 2.0 device into a USB 3.0 port, it won't receive power at USB 3.0 speeds but WILL receive power faster than at USB 2.0 speeds. A USB 3.0 port can transmit more power and will usually be able to push more power to a device than a USB 2.0 port.
