Usb power delivery

A method of power delivery from a USB dock to a peripheral device, the USB dock comprising:

• a USB data hub that does not provide negotiated power levels to devices connected to the USB dock;
• at least a first port including a USB connection for connecting to a host device;
• at least one second port for connecting to at least one peripheral device, the at least one second port including at least a USB connection connected to the USB data hub and a power connection;
• a power source capable of providing power at a plurality of different power levels, the power source being connected to the power connection of the at least one second port;
• and
• a power controller having a first connection to the power source, a second connection to the USB data hub and a third connection to the at least one second port, wherein the second connection is a USB data connection and the third connection is a power signalling connection;
• wherein the method comprises the power controller:
• receiving instructions from a host device connected to the first port via the USB data hub and the second connection, the instructions instructing the power controller to control the power source to provide power to a peripheral device connected to the at least one second port;
• communicating with the peripheral device over the power signalling connection to determine parameters for power to be provided to the peripheral device;
• and
• controlling the power source to provide power at one of the plurality of different power levels to the peripheral device via the power connection based on the instructions from the host device and the determined parameters.