METHOD FOR DETECTING FOREIGN MATERIAL, AND APPARATUS AND SYSTEM THEREFOR

A wireless power receiver that receives power from a wireless power transmitter, the wireless power receiver including a communication unit configured to communicate with the wireless power transmitter; and a controller, wherein the controller generates a foreign object detection (FOD) status packet including information on a reference quality factor or a reference peak frequency, and a packet having a length of eight bit, wherein the communication unit transmits the FOD status packet to the wireless power transmitter, wherein the communication unit receives, from the wireless power transmitter, a foreign object detection indicator indicating whether a foreign object is present in a charging area of the wireless power transmitter in response to the MD status packet, wherein the controller performs differential bi-phase encoding for binary data of the packet having a length of eight bits, wherein the controller performs byte encoding for binary data of the differential bi-phase encoded packet, wherein the communication unit transmits the byte encoded packet to the wireless power transmitter, and wherein the byte encoding is inserting a start bit, a stop bit, and a parity bit into binary bit, stream of the differential bi-phase encoded packet.