Power transmission device and method for detecting metal substance

A power transmission device comprising:

• an induction circuit configured to transmit a wireless power signal through a charging pad and receive a response signal from an external device;
• and
• at least one processor operatively connected to the induction circuit,
• wherein the at least one processor is configured to:
• enter, in response to detecting a metal substance on the charging pad, a wireless charging protection mode for wireless charging of the external device,
• identify whether the external device remains on the charging pad based on packet information included in the response signal received from the external device,
• measure a current value of the wireless power signal when the external device is removed from the charging pad, and
• identify whether the metal substance remains on the charging pad based on a variation of the measured current value, and
• release the wireless charging protection mode when both the metal substance and the external device are removed from the charging pad.

A method for operating an electronic device, comprising:

• entering, in response to detecting a metal substance on a charging pad of the electronic device, a wireless charging protection mode for wireless charging of an external device;
• measuring a current value of a wireless power signal transmitted through the charging pad on the wireless charging protection mode;
• identifying whether the metal substance remains on the charging pad based on a variation of the current value;
• identifying whether the external device remains on the charging pad based on packet information included in a response signal received from the external device;
• and
• releasing the wireless charging protection mode when both the metal substance and the external device are removed from the charging pad.