USB hub power supply

I have a USB 2.0 hub, which is able to provide 100 mA per port. I was checking my devices and I saw that my bluetooth dongle requires 200 mA. The hub has an AC connector.

Can someone tell me what voltage and polarity is required here? I have a costumizable AC and I don’t want to ruin anything.


If you read on the USB hub it says…
My guess is 12V

There’s nothing on the circuit nor the housing.

Can you go to mfg’s website for info?

It’s a noname hub. :wink:

My 7-port D-Link is 5VDC, 3A center positive.
I think you need a new hub unless you don’t mind burning stuff up.
:eek: :stuck_out_tongue:

I would think that 5v would be the most common as that is what usb uses. I think I would just get a new hub too though, as even if it is 5v, you don’t know the polarity. I wouldn’t risk frying my stuff. Its also possible that they use another voltage, so they can use the same power adapter as other devices (less parts to make for their product lline), and the unit converts to 5v, so its risky guessing.

Unless it complins, I’d expect you could get away with a 200mA device on one port, if the other ports add up to less than 200.

It stems from the device power grading.

A standard high power device, which can ONLY be driven by a system port or powered (“self powered”) hub, is 500mA.
A standard low power device, is 100mA.

So a 4 port, unpowered (“bus powered”) hub, can drive 4 standard low power devices.

This is complicated by self powered devices (eg. Printer, camera docking station with PSU) which consume no power from the bus, or a nominal 2mA for presence detection. devices that lower than the 100mA, and devices that are higher.

Golden rule, if what you connect to an unpowered hub, plus the small demand of the hub itself, exceeds 500mA, then you WILL have problems - if the system is doing it’s job, it will force an overcurrent shutdown of the hub or the devices on it.

If you can find the hub in device manager (generic hub, not “root”), then the “power” tab will tell you the current device power indications - they are power “requests”, not measurements, as each device declares a maximum requirement, and then the USB subsystem should allow or deny it accordingly.

PS. My external bus powered hub is detected as self powered, and classified as 500mA per port, completely wrong!