Wireless charging method and system for detecting foreign material during wireless charging

1. An electronic device, comprising:

a battery;

a coil;

a wireless charging reception circuit;

a power management module configured to control a charging state of the battery using a voltage supplied from the wireless charging reception circuit; and

a processor configured to:

receive power from a wireless charging transmission device through the coil,

determine whether a predetermined condition is satisfied while the battery is charging using the received power, and

in response to determining that the predetermined condition is satisfied, adjust a load of supply power supplied to the power management module from the wireless charging reception circuit by lowering a current of the supply power supplied to the power management module from the wireless charging reception circuit, and transmit a foreign material detection request packet to the wireless charging transmission device.

2. The electronic device of claim 1 , wherein the processor is further configured to maintain a charging state of the battery even though the wireless charging transmission device stops transmitting the power in response to the foreign material detection request packet.

3. The electronic device of claim 1 , wherein the processor is further configured to transmit the foreign material detection request packet at a predetermined period.

4. The electronic device of claim 3 , wherein the processor is further configured to decrease the predetermined period as a temperature of at least one component of the electronic device increases.

5. The electronic device of claim 1 , wherein the processor is further configured to transmit the foreign material detection request packet when a temperature of at least one component of the electronic device increases above a threshold value.

6. The electronic device of claim 1 , wherein the processor is further configured to transmit the foreign material detection request packet in response to a request from the wireless charging transmission device.

7. An apparatus for performing wireless charging transmission, the apparatus comprising:

a transmission coil;

a wireless charging transmission circuit; and

a controller configured to:

configure charging, based on an exchange of at least one predetermined packet with a detected wireless charging reception device,

transmit power to the detected wireless charging reception device, based on the configured charging,

temporarily stop transmitting power in response to receiving a foreign material detection request packet from the wireless charging reception device while the power is being transmitted, wherein the wireless charging reception device is configured to, before transmitting the foreign material detection request packet to the apparatus, adjust a load of supply power supplied to the power management module from the wireless charging reception circuit by lowering a current of the supply power supplied to the power management module from the wireless charging reception circuit,

detect whether foreign material is present based on a resonance characteristic of the transmission coil while transmission of the power is temporarily stopped,

completely stop transmitting the power in response to detecting that the foreign material is present, and

reinitiate the transmission of the power in response to detecting that the foreign material is not present.

8. The apparatus of claim 7 , wherein the controller is further configured to:

measure a first Q value of the transmission coil by generation of a first Q ping before the wireless charging reception device is detected,

measure a second Q value of the transmission coil by generation of a second Q ping before the power is transmitted,

measure a third Q value of the transmission coil while transmission of the power is temporarily stopped, and

determine that the foreign material is present when the third Q value satisfies a predetermined condition.

9. The apparatus of claim 8 , wherein the controller is further configured to determine that the foreign material is present when the third Q value is smaller than a threshold value.

10. The apparatus of claim 8 , wherein the controller is further configured to determine that the foreign material is present when the third Q value is less than or equal to a predetermined ratio of the second Q value.

11. The apparatus of claim 8 , wherein the controller is further configured to determine that the foreign material is present when the third Q value is less than or equal to a predetermined ratio of the first Q value.

12. The apparatus of claim 7 , wherein the controller is further configured to stop transmitting the power when a predetermined delay period passes after receiving a foreign material detection request packet.

13. The apparatus of claim 7 , wherein the controller is further configured to:

receive a control error packet (CEP) from the wireless charging reception device after a foreign material detection request packet is received, and

stop transmitting the power when a predetermined delay period passes after receiving the CEP.

14. A method of performing wireless charging by an electronic device, the method comprising:

receiving power from a wireless charging transmission device;

determining whether a predetermined condition is satisfied while a battery is charging using the received power; and

in response to determining that the predetermined condition is satisfied, adjusting a load of supply power supplied to the power management module from the wireless charging reception circuit by lowering a current of the supply power supplied to the power management module from the wireless charging reception circuit, and transmitting a foreign material detection request packet to the wireless charging transmission device.

15. The method of claim 14 , further comprising maintaining a charging state of the battery even though the wireless charging transmission device stops transmitting the power due to the foreign material detection request packet.

16. The method of claim 14 , wherein the foreign material detection request packet is transmitted at a predetermined period.

17. The method of claim 14 , wherein determining that the predetermined condition is satisfied comprises determining that a temperature of at least one component of the electronic device increases above a threshold value.