5
Powering Mode
A USB hub could be powered by the USB bus (bus-power mode), or be powered by
the power supply (self-power mode). Bus-power mode is simpler as it does not need
to have external power supply, but it has quite limited ability to power the devices on
the USB hub. When you are trying to power more devices with higher current, it is
recommended to use the self-power mode.
This USB hub supports both bus-power mode and self-power mode.
Self-Power Mode
This USB hub in self-power mode can output up to 2,000mA current for all USB ports.
When you attach Ace4U USB hub to Raspberry Pi A+ or 3A+, it will take power from
Raspberry Pi, or supply power to Raspberry Pi, and work in self-power mode.
If you use a USB - micro USB cable to connect Ace4U USB hub to other models of
Raspberry Pi, and you connect power supply to the USB hub (via the power micro
USB port or the white JST XH2.54 2-pin connector on board), then it is still working in
self-power mode. It will also back-power the Raspberry Pi, unless you remove the
resistor R8 on board.
Bus-Power Mode
If you use a USB - micro USB cable to connect Ace4U USB hub to other models of
Raspberry Pi, and you don’t connect power supply to the USB hub, then it is will work
in bus-power mode, and it will draw power from the USB bus on Raspberry Pi. In this
case it can output up to 500mA current for all USB ports.
