FIG. 31 is a flow chart illustrating another method of determining the existence or non-existence of the external metal material according to an embodiment of the present disclosure;
FIG. 32 is a flow chart illustrating a method of detecting a type of external material, and an alignment state and a capacitance of the receiver based on a change rate for each period of an attenuation factor;
FIG. 33 is a flow chart illustrating a method of performing communication in a wireless power transmitter according to an embodiment of the present disclosure;
FIG. 34 is a flow chart illustrating a method of suspending the transmission of power in a wireless manner; and
FIGS. 35, 36 and 37 are graphs illustrating a change of an attenuation factor according to the type of an external material, and
FIGS. 38, 39 and 40 are graphs illustrating a change of an attenuation factor for each period when there is a receiver.
DETAILED DESCRIPTION OF THE INVENTION
The technologies disclosed herein may be applicable to wireless power transfer (contactless power transfer). However, the technologies disclosed herein are not limited to this, and may be also applicable to all kinds of power transmission systems and methods, wireless charging circuits and methods to which the technological spirit of the technology can be applicable, in addition to the methods and apparatuses using power transmitted in a wireless manner.
