Receiving coil and foreign object detecting apparatus in multiple charging condition using plurality of transmitting coils

A receiving coil and foreign object detecting apparatus comprising:

• a charger that transmits a foreign object detection signal to detect whether or not at least one of a wireless power receiving apparatus and a foreign object is disposed on a charging pad, and selectively transmits a wireless power signal to charge the wireless power receiving apparatus;
• and
• a controller that controls the charger so that the wireless power signal and the foreign object detection signal are transmitted, and detects, based on the foreign object detection signal, presence of at least one of the foreign object and the wireless power receiving apparatus based on an output voltage detected by the charger,
• wherein the charger comprises:
• a transmitter that transmits the wireless power signal and the foreign object detection signal, resonates a transmitting coil based on a first resonance value for transmitting the wireless power signal, and prevents a signal induced from neighboring other transmitting coils;
• and
• a resonance variable portion that varies the first resonance value to a second resonance value for transmitting the foreign object detection signal,
• wherein the transmitter comprises:
• the transmitting coil disposed on a substrate and configured to transmit the wireless power signal;
• a resonance loop disposed in an area of the transmitting coil;
• and
• an induced signal processor that prevents interference of the signal induced by the neighboring other transmitting coils,
• wherein the induced signal processor comprises a peak detection circuit,
• wherein the peak detection circuit comprises a diode and a capacitor connected to each other and has a period of a signal for detection that is longer than a detected voltage observation time to have a maximum value of a frequency of the signal for detection as a representative value of the frequency of the signal for detection.