WIRELESS POWER TRANSMISSION METHOD AND DEVICE THEREFOR

A method for transmitting wireless power , the method performed by a wireless power transmitter and comprising: receiving, from a wireless power receiver, a control error (CE) based data packet or a received power (RP) based data packet; transmitting, to the wireless power receiver, a bit pattern requesting permission to communicate based on receiving the CE based data packet or the RP based data packet; receiving, from the wireless power receiver, a response packet for granting the permission; transmitting, to the wireless power receiver, a capability data packet providing information for a capability of the wireless power transmitter after receiving the response packet; receiving, from the wireless power receiver, a renegotiation data packet requesting the wireless power transmitter to proceed to a renegotiation phase; transmitting, to the wireless power receiver, an acknowledgement (ACK) response related to the wireless power transmitter having switched to the renegotiation phase based on receiving the renegotiation data packet; receiving, from the wireless power receiver in the renegotiation phase, a first specific request data packet including information for a requested guaranteed power level; transmitting, to the wireless power receiver in the renegotiation phase, an ACK response to accept the requested guaranteed power level based on receiving the first specific request data packet; receiving, from the wireless power receiver in the renegotiation phase, a second specific request data packet to end the renegotiation phase; and transmitting, to the wireless power receiver, an ACK response related to the wireless power transmitter having concluded the renegotiation phase successfully and having switched to a power transfer phase.