One inductive sensor is configured to maintain a fixed frequency in a resonant circuit. One apparatus includes an inductance-to-digital converter (LDC). The LDC includes a digital filter to measure an inductance change of a sensor and convert the inductance change to a digital value. The LDC further includes a digital control loop to maintain a fixed frequency in the sensor. The sensor forms an oscillator in the digital control loop. An output of the digital control loop is representative of the inductance change of the sensor.

The disclosure includes a foreign object detection circuit and a foreign object detection method. The method comprises: step a) establishing a communication link between a transmitter and a receiver in a wireless power transmission system; step b) performing, by the transmitter and the receiver, wireless power transmission based on the magnetic coupling; and step c) measuring a quality factor of a receiver terminal, and determining whether a foreign object exists in the wireless power transmission system or not based on the quality factor. In accordance with a foreign object detection circuit and a foreign object detection method provided by the present invention, the problem that the foreign object cannot be detected effectively in the prior art is solved.

One inductive sensor is configured to maintain a fixed frequency in a resonant circuit. One apparatus includes an inductance-to-digital converter (LDC). The LDC includes a digital filter to measure an inductance change of a sensor and convert the inductance change to a digital value. The LDC further includes a digital control loop to maintain a fixed frequency in the sensor. The sensor forms an oscillator in the digital control loop. An output of the digital control loop is representative of the inductance change of the sensor.

A method for foreign object detection for an induction charging device is described, including an oscillator circuit, in particular, for a hand-held power tool, a resonance frequency and an associated actual quality of the oscillator circuit being detected and the actual quality is subsequently compared to a setpoint quality as a function of the resonance frequency and a decision is made about the presence of a foreign object based on a defined setpoint quality range. The method provides that an internal temperature of induction charging device is detected, in particular, during the wireless energy transmission, and the actual quality is multiplied by a correction factor based on the internal temperature. Also, an induction charging device is described that includes an oscillator circuit and a control and regulating unit, as well as at least one temperature sensor for carrying out the method.

The present invention relates to a portable detector for metal detection, the detector including: a head extending longitudinally and comprising an inductive transducer for generating a magnetic field and measuring a variation in inductance, a body including a controller programmed to control the activation or the deactivation of a standby function of the detector, and a sensor for measuring one or more of the displacement of the detector or the orientation of the detector, wherein the controller controls the activation of the standby function as a function of signals received from the inductive transducer and from the sensor.

A wireless transmitter with Q-factor measurement is presented. In some embodiments, a method of performing a measurement test in a wireless power transmitter includes adjusting an input voltage to a bridge circuit; setting up transistors in the wireless power transmitter to form an LC oscillating circuit that includes a transmit coil and a capacitor circuit; measuring a VDET sinusoidal voltage from the LC oscillating circuit; and determining a result from the VDET sinusoidal voltage. The result can be calculation of a Q-factor and/or determination of presence of a foreign object.

The disclosure includes a foreign object detection circuit and a foreign object detection method. The method comprises: step a) establishing a communication link between a transmitter and a receiver in a wireless power transmission system; step b) performing, by the transmitter and the receiver, wireless power transmission based on the magnetic coupling; and step c) measuring a quality factor of a receiver terminal, and determining whether a foreign object exists in the wireless power transmission system or not based on the quality factor. In accordance with a foreign object detection circuit and a foreign object detection method provided by the present invention, the problem that the foreign object cannot be detected effectively in the prior art is solved.

A wireless transmitter with Q-factor measurement is presented. In some embodiments, a method of performing a measurement test in a wireless power transmitter includes adjusting an input voltage to a bridge circuit; setting up transistors in the wireless power transmitter to form an LC oscillating circuit that includes a transmit coil and a capacitor circuit; measuring a VDET sinusoidal voltage from the LC oscillating circuit; and determining a result from the VDET sinusoidal voltage. The result can be calculation of a Q-factor and/or determination of presence of a foreign object.

A foreign object detector, a foreign object detection system and a method for operating the foreign object detector are disclosed. In an embodiment, a foreign object detector includes a conducting wire with a first section and a second section, a first node, a second node and an intermediate node, wherein the first section electrically connects the first node to the intermediate node and has a plurality of three or more vertical segments, and wherein the second section electrically connects the intermediate node to the second node and has a plurality of three or more horizontal segments.

Man-portable locator systems for locating buried or otherwise inaccessible pipes, conduits, cables, wires, and/or inserted transmitters using magnetic field antenna arrays and signal processing to analyze and display information about multiple buried utilities simultaneously are disclosed.