Charging device

A method for charging a portable device via a universal serial bus of a charging device, the method comprising:

• supplying current to a portable device from a power supply of the charging device through a voltage bus (VBUS);
• measuring the amount of current supplied to the portable device though the voltage bus (VBUS);
• notifying the portable device coupled to the charging device of a signal indicating suppliable amount of current;
• obtaining information identifying the portable device at a control unit coupled to the portable device;
• selecting an available power indicating circuit based on the obtained information by referring to a previously stored table which defines, for a plurality of portable devices, correspondence between information identifying the portable devices and available power indicating circuits, and
• activating only the selected available power indicating circuit at a time of actual operation,
• wherein, when the control unit does not obtain from a portable device coupled thereto information identifying the portable device, or when an available power indicating circuit corresponding to information identifying the portable device is not defined in the table, the control unit activates the available power indicating circuits one by one, causes a measurement unit to measure the amount of current supplied to the portable device through a voltage bus (VBUS), stores a measurement result in a storage unit, selects, by referring to the storage unit, an available power indicating circuit exhibiting a maximum current supply amount, and activates only the selected available power indicating circuit at a time of actual operation.

A method for charging a portable device via a universal serial bus of a charging device, the method comprising:

• supplying current to a portable device coupled through a voltage bus (VBUS);
• measuring the amount of current supplied to the portable device through the voltage bus (VBUS);
• notifying the portable device coupled to the charging device of a signal indicating suppliable amount of current, the notifying being done through a data line by a plurality of available power indicating circuits, each circuit having different current supplying ability;
• at the time of adjustment, activating through a control unit the available power indicating circuits one by one, measuring the amount of current supplied to the portable device, and storing in a storage unit a measurement result;
• selecting, by referring to the storage unit, an available power indicating circuit exhibiting a maximum current supply amount;
• and
• activating only the selected available power indicating circuit at a time of actual operation,
• wherein, at the time of adjustment, the control unit does not obtain from a portable device information identifying the portable device.