WIRELESS CHARGING FOREIGN OBJECT DETECTION

A method of foreign object detection for a wireless power transmitter. The method includes determining a vector impedance of a near-field communication (NFC) coil with an NFC chip. The determined vector impedance includes an impedance amplitude component and an impedance phase component. The impedance amplitude component and the impedance phase component are compared to a baseline impedance amplitude and a baseline impedance phase. A determination as to whether an object is present within an inductive charging area of the wireless power transmitter is made when a difference between the determined vector impedance, and the baseline impedance amplitude and the baseline impedance phase, exceeds a delta threshold. A ping signal is generated with a charging source coil when the object is determined to be present. A foreign object is detected based on whether a response signal to the ping signal is received from the object.