Mobile device and charging apparatus

1. A charging device comprising:

a receptacle upon which a plurality of mobile devices that issue charge order instructions are placed, each of the plurality of the mobile devices includes a rechargeable battery, a receiver coil that receives AC power, a rectifier that rectifies the AC power into DC power, a plurality of capacitors disposed between the receiver coil and the rectifier, and a switch that selectably connects or disconnects the receiver coil one or more of the capacitors;

a transmitter coil that moves on a plane parallel to the receptacle and wirelessly transmits AC power to a selected mobile device of the plurality of mobile devices placed on the receptacle; and

a controller that determines a mobile charge order of the plurality of mobile devices based on capacitances of capacitors connected to respective receiver coils of the plurality of mobile devices, and controls a movement of the transmitter coil to a predetermined location in the receptacle on the basis of the mobile charge order so as to charge the rechargeable battery of the selected mobile device.

2. The charging device of claim 1 , wherein

said controller changes the mobile charge order when a charge level of the selected mobile device reaches a predetermined threshold and another mobile device has a charge level lower than said predetermined threshold.

3. The charging device of claim 2 , wherein

said controller continues charging of the selected mobile device when no other mobile device has a charge level lower than the predetermined threshold.

4. The charging device of claim 2 , wherein

said controller controls charging of a first of two mobile devices that have a same charge level, said first of two mobile devices having a higher priority than the other of the two mobile devices.

5. The charging device of claim 2 , wherein

said transmitter coil is configured to move to and charge a nearest of two mobile devices that have a same charge level.

6. A method for charging a selected mobile device, comprising:

detecting respective positions on a receptacle of a plurality of mobile devices that issue charge order instructions, each of said plurality of mobile devices includes a rechargeable battery, a receiver coil that receives AC power, a rectifier that rectifies the AC power into DC power, a plurality of capacitors connected between the receiver coil and the rectifier, and a switch that selectably connects or disconnects the receiver coil to one or more of the capacitors;

comparing charge order instructions from the plurality of mobile devices and determining a selected mobile device with a lowest charge based on capacitances of the plurality of capacitors that are connected to the receiver coil, said selected mobile device being one of the plurality of mobile devices;

moving a transmitter coil to the selected mobile device; and

charging the selected mobile device to a predetermined charge threshold.

7. The method of claim 6 , further comprising:

repeating said comparing, moving and charging steps for another mobile device of the plurality of mobile devices when said another mobile device has a charge level lower than said predetermined threshold.

8. The method of claim 7 , further comprising:

continuing said charging of the selected mobile device when no other mobile device has a charge level lower than the predetermined threshold.

9. The method of claim 6 , further comprising:

determining that two of the mobile devices have a same charge level; and

charging a first of the two mobile devices that has an assigned higher priority.

10. The method of claim 6 , further comprising:

determining that two of the mobile devices have a same charge level;

moving the transmitter coil to a nearest of the two mobile devices; and

charging the nearest of the two mobile devices.

11. A mobile device comprising:

a rechargeable battery;

a receiver coil that outputs AC power received from a charging apparatus that wirelessly charges the rechargeable battery;

a rectifier that rectifies the AC power output by the receiver coil into DC power;

a capacitor that is switchably connected between the receiver coil and the rectifier;

a charger that charges the rechargeable battery with the DC power rectified by the rectifier, and measures the charge level of the rechargeable battery;

a switch that selectably connects or disconnects the receiver coil and the capacitor; and

a charging controller that controllably operates the switch to change a capacitance level of the mobile device by disconnecting the capacitor from the receiver coil when the charge level of the rechargeable battery is equal to or greater than a predetermined threshold value, and connects the capacitor to the receiver coil with the switch when the charge level of the rechargeable battery is less than the threshold value.

12. The mobile device of claim 11 , further comprising:

a second capacitor, wherein

said charging controller operates the switch to connect the second capacitor to the receiver coil and disconnect the first capacitor from the receiver coil so as to change the capacitance level of the mobile device.

13. The mobile device of claim 12 , further comprising:

a third capacitor, wherein

said charging controller operates the switch to connect the third capacitor to further change the capacitance level of the mobile device,

the switch having a first state that is not connected to a capacitor and produces a capacitance level that indicates a first priority setting for charging the mobile device;

the switch having a second state that is connected to the capacitor and produces a second capacitance level that indicates a second priority setting for charging the mobile device;

the switch having a third state that is connected to a second capacitor and produces a third capacitance level that indicates a third priority setting for charging the mobile device; and

the switch having a fourth state that is connected to a third capacitor and produces a second capacitance level that indicates a fourth priority setting for charging the mobile device.

14. The mobile device of claim 11 , further comprising:

a second capacitor, wherein said charging controller operates the switch to connect the second capacitor from the receiver coil and disconnect the first capacitor to the receiver coil so as to change the capacitance of the mobile device; and

a second switch that is controlled by the charging controller to switchably connect at least an other capacitor, said other capacitor changing the capacitance level of the mobile device along with at least one of the first capacitor and the second capacitor when connected to the receiver coil.