METHOD AND APPARATUS FOR CHARGING ELECTRONIC DEVICE WITH USB CONNECTION

1 - 15 . (canceled)

16 . A method for charging a first electronic device by a second electronic device with a connection which can also provide data communication thereon, comprising, at the side of the first electronic device, the steps of:

receiving a power supply at a first voltage level from the second electronic device;

detecting whether there is data communication on the connection,

if there is no data communication on the connection, transmitting a message to the second electronic device to request for being charged at a second voltage level which is greater than the first voltage level; and

receiving a power supply at the second voltage level from the second electronic device.

17 . The method according to claim 16 , wherein the connection is in conformity with the universal serial bus (USB) protocol.

18 . The method according to claim 17 , further comprising detecting there is no data communication on the USB connection when the USB_DP and USB_DN pins of a USB port of the second electronic device are shorted.

19 . The method according to claim 17 , wherein the first voltage level is 5V DC and the second voltage level is 12V DC.

20 . The method according to claim 17 , further comprising transmitting the message via the USB_DP pin of a USB port of the first electronic device.

21 . The method according to claim 17 , wherein the message is transmitted periodically.

22 . The method according to claim 21 , wherein the message is in a form of a heart beat pulse.

23 . A method for charging a first electronic device by a second electronic device with a connection which can also provide data communication thereon, comprising, at the level of the second electronic device, the steps of:

outputting a first voltage level to charge the first device; and

upon receipt of a message from the first electronic device to request for being charged at a second voltage level which is greater than the first voltage level, switching to output a second voltage level to charge the first device.

24 . The method according to claim 23 , wherein the connection is in conformity with the universal serial bus (USB) protocol.

25 . The method according to claim 24 , further comprising receiving the message via the USB_DN pin of a USB port of the second electronic device.

26 . The method according to claim 24 , further comprising

switching back to charge the first device at the first voltage level if no additional message from the first electronic device to request for being charged at a second voltage level is received within a determined time period.

27 . An apparatus provided with a USB port and receiving a power supply at a first voltage level from an electronic device with USB connection, comprising a processor configured to:

detect whether there is data communication on the USB connection;

transmit a message to the electronic device to request for being charged at a second voltage level which is greater than the first voltage level, if there is no data communication on the USB connection; and

receive a power supply at the second voltage level from the electronic device.

28 . An apparatus provided with a USB port and outputting a first voltage level to charge an electronic device with USB connection, comprising a processor configured to:

switch to output a second voltage level which is greater than the first voltage level to charge the first device upon receipt of a message from the electronic device to request for being charged at the second voltage level.

29 . The apparatus according to claim 28 , wherein the apparatus is an electronic device which provides power supply to another electronic device from its battery or from an AC power source.

30 . The apparatus according to claim 28 , wherein the apparatus is an adapter connected to an AC power source.