Adaptive foreign object detection avoidance in a multi-coil wireless charging device

1. A method for operating a charging device, comprising:

detecting the presence of a foreign object in proximity to at least one charging coil of a plurality of charging coils in the charging device that is selected for supplying charging energy to a receiving device;

determining whether one or more other charging coils of the plurality of charging coils is capable of supplying charging energy to the receiving device;

determining, for each of the one or more other charging coils, whether the foreign object is in proximity to the other charging coil; and

selecting at least one of the one or more other charging coils that is not in proximity to foreign object for supplying charging energy to the receiving device.

2. The method of claim 1 , further comprising:

setting a permanent foreign object detection (FOD) state for the receiving device when all of the one or more other charging coils is determined to be in proximity to the foreign object.

3. The method of claim 2 , further comprising:

determining whether the foreign object is removed after setting the permanent FOD state for the receiving device; and

resetting the FOD state for the receiving device after the foreign object is removed.

4. The method of claim 1 , wherein the determination of whether the one or more other charging coils is capable of supplying charging energy includes access a stored list of predetermined coils that are capable of supplying charging energy to the receiving device.

5. The method of claim 4 , wherein the list of predetermined coils that are capable of supplying charging energy to the receiving device is predetermined during an initial setup when the receiving device is placed in proximity to the charging device and capable of responding to a ping from at least one of plurality of charging coils.

6. The method of claim 1 , wherein the determination of whether the one or more other charging coils is capable of supplying charging energy includes determination of available coils may be performed after detecting the presence of the foreign object and further includes scanning to determine whether one or more of the plurality of charging coils in the charging device is capable of supplying charging energy to the receiving device.

7. The method of claim 6 , wherein scanning to determine whether one or more of the plurality of charging coils in the charging device is capable of supplying charging energy to the receiving device includes at least one of passive and active pinging with the charging device.

8. A charging device, comprising:

a charging circuit; and

a controller configured to:

detect the presence of a foreign object in proximity to at least one charging coil of a plurality of charging coils in the charging device that is selected for supplying charging energy to a receiving device;

determine whether one or more other charging coils of the plurality of charging coils is capable of supplying charging energy to the receiving device;

determine, for each of the one or more other charging coils, whether the foreign object is in proximity to the other charging coil; and

select at least one of the one or more other charging coils that is not in proximity to foreign object for supplying charging energy to the receiving device.

9. The charging device of claim 8 , wherein the controller is configured to:

set a permanent foreign object detection (FOD) state for the receiving device when all of the one or more other charging coils is determined to be in proximity to the foreign object.

10. The charging device of claim 9 , wherein the controller is configured to:

determine whether the foreign object is removed after setting the permanent FOD state for the receiving device; and

reset the FOD state for the receiving device after the foreign object is removed.

11. The charging device of claim 8 , wherein the controller is configured to access a stored list of predetermined coils that are capable of supplying charging energy to the receiving device when determining whether the one or more other charging coils is capable of supplying charging energy includes.

12. The charging device of claim 11 , wherein the controller is configured to predetermine the list of predetermined coils that are capable of supplying charging energy to the receiving device during an initial setup when the receiving device is placed in proximity to the charging device and capable of responding to a ping from at least one of plurality of charging coils.

13. The charging device of claim 8 , wherein the determination of whether the one or more other charging coils is capable of supplying charging energy includes determination of available coils may be performed after detecting the presence of the foreign object and further includes scanning to determine whether one or more of the plurality of charging coils in the charging device is capable of supplying charging energy to the receiving device.

14. The charging device of claim 13 , wherein scanning to determine whether one or more of the plurality of charging coils in the charging device is capable of supplying charging energy to the receiving device includes at least one of passive and active pinging with the charging device.