Abstract: A wireless power transmission system has a wireless power receiving device that is located on a charging surface of a wireless power transmitting device. The wireless power receiving device has a wireless power receiving coil and the wireless power transmitting device has a wireless power transmitting coil array. Signal measurement circuitry coupled to the coil array may make measurements while the control circuitry uses the inverter circuitry to apply excitation signals to each of the coils. Foreign objects on the coil array such as metallic objects without wireless power receiving coils can be detected using foreign object detection. When multiple wireless power receiving devices are present on the wireless power transmitting device, steps may be taken to isolate measurements from the coils associated with each wireless power receiving device. Foreign object detection may then be performed on these modified measurements.

Abstract: A wireless power transmitting device transmits wireless power signals to a wireless power receiving device. The wireless power receiving device has a rectifier and a wireless power receiving coil that receives wireless power signals. The wireless power transmitting device uses a layer of coils to transmit the wireless power signals. A dielectric layer in the wireless power transmitting device defines a charging surface that receives the wireless power receiving device. A layer of temperature sensors is interposed between the layer of coils and the dielectric layer. Control circuitry in the wireless power transmitting device uses temperature information from the temperature sensors to determine whether a foreign object such as a coin is present on the charging surface.

Abstract: A wireless power transmitting device transmits wireless power signals to a wireless power receiving device. The wireless power receiving device has a rectifier and a wireless power receiving coil that receives wireless power signals. The wireless power transmitting device uses a layer of coils to transmit the wireless power signals. A dielectric layer in the wireless power transmitting device defines a charging surface that receives the wireless power receiving device. A layer of temperature sensors is interposed between the layer of coils and the dielectric layer. Control circuitry in the wireless power transmitting device uses temperature information from the temperature sensors to determine whether a foreign object such as a coin is present on the charging surface.

Abstract: A wireless power transmission system has a wireless power receiving device with a wireless power receiving coil that is located on a charging surface of a wireless power transmitting device with a wireless power transmitting coil array. Control circuitry in the wireless power transmitting device may use inverter circuitry to supply alternating-current signals to coils in the coil array, thereby transmitting wireless power signals. The control circuitry may also be used to detect foreign objects on the coil array such as metallic objects without wireless power receiving coils. For example, control circuitry may use inductance measurements from the coils in the coil array to identify segments of the coil array that correspond to potential wireless power receiving devices. The control circuitry may control wireless power transmission based on a comparison between the number of identified segments corresponding to potential wireless power receiving devices and a number of received device-identifiers.

Abstract: A wireless power transmission system has a wireless power receiving device that is located on a charging surface of a wireless power transmitting device. The wireless power receiving device has a wireless power receiving coil and the wireless power transmitting device has a wireless power transmitting coil array. Signal measurement circuitry coupled to the coil array may make measurements while the control circuitry uses the inverter circuitry to apply excitation signals to each of the coils. Foreign objects on the coil array such as metallic objects without wireless power receiving coils can be detected using foreign object detection. When multiple wireless power receiving devices are present on the wireless power transmitting device, steps may be taken to isolate measurements from the coils associated with each wireless power receiving device. Foreign object detection may then be performed on these modified measurements.

Abstract: A wireless power transmission system has a wireless power receiving device with a wireless power receiving coil that is located on a charging surface of a wireless power transmitting device with a wireless power transmitting coil array. Control circuitry in the wireless power transmitting device may use inverter circuitry to supply alternating-current signals to coils in the coil array, thereby transmitting wireless power signals. The control circuitry may also be used to detect foreign objects on the coil array such as metallic objects without wireless power receiving coils. For example, control circuitry may use inductance measurements from the coils in the coil array to determine a probability value indicative of whether a foreign object is present on the charging surface. The control circuitry may compare the probability value to a threshold and take suitable action in response to the comparison.

Abstract: A wireless power transmission system has a wireless power receiving device with a wireless power receiving coil that is located on a charging surface of a wireless power transmitting device with a wireless power transmitting coil array. Control circuitry in the wireless power transmitting device may use inverter circuitry to supply alternating-current signals to coils in the coil array, thereby transmitting wireless power signals. The control circuitry may also be used to detect foreign objects on the coil array such as metallic objects without wireless power receiving coils. For example, control circuitry may use inductance measurements from the coils in the coil array to identify segments of the coil array that correspond to potential wireless power receiving devices. The control circuitry may control wireless power transmission based on a comparison between the number of identified segments corresponding to potential wireless power receiving devices and a number of received device-identifiers.