A system may include a resonant phase sensing system comprising a resistive-inductive-capacitive sensor and a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor, and a compensation circuit. The measurement circuit may be configured to use a phase detector to measure phase information associated with the resistive-inductive-capacitive sensor and based on the phase information, determine a displacement of a metal plate relative to the resistive-inductive-capacitive sensor. The compensation circuit may be configured to detect a change in a physical property associated with the resistive-inductive-capacitive sensor other than the displacement and compensate the phase information to correct for the change in the physical property.

An inductive sensor is proposed which comprises at least one resonant circuit, an evaluation device which in a measuring phase evaluates oscillations of the at least one resonant circuit for generating sensor signals, an energy storage device, and a transfer device which in a relaxation phase of the at least one resonant circuit stores oscillation energy of the at least one resonant circuit in the energy storage device.

A proximity sensor and a method of changing a detection distance are provided to suppress changes in a consumption current of an oscillation circuit. The proximity sensor includes an oscillation circuit having an oscillation amplitude that changes with a feedback current, a comparing part comparing the oscillation amplitude with a threshold, a detecting part detecting a target object based on a comparison result of the comparing part, a voltage value signal generating part generating a voltage value signal based on the feedback current and the detection distance, a threshold setting part setting an analog signal converted from the voltage value signal as the threshold, a current value signal generating part generating a current value signal based on the detection distance and the voltage value signal, and a current value setting part setting an analog signal converted from the current value signal as a current value of the feedback current.

A proximity sensor or switch having a sensing coil, an oscillator connected to the coil, a comparator connected to the oscillator, a reference voltage module connected to the comparator, and an output driver connected to the comparator. The voltage module may incorporate a resistor having an end connected to a high side of a power source, and a digital potentiometer having a first end connected to another end of the resistor and to the comparator, and having a second end connected to a ground side of the power source. The digital potentiometer may have a resistance that is varied with a signal. A variation of the resistance for the digital potentiometer may result in a change of a voltage from the reference voltage module which further changes a switching distance of the proximity switch to a predetermined value.

Front-end circuits that combine inductive and capacitive sensing are described. In one embodiment, an apparatus includes a plurality of inductive elements, an inductive measurement circuit, and a frequency divider circuit. The inductive measurement circuit is to output a first signal with a first frequency. The first signal is associated with an inductance change of one of the inductive elements. A feedback circuit can maintain the sinusoidal operation of the first signal. The frequency divider circuit can generate a second signal with a second frequency that is lower than the first frequency.

The present invention provides a proximity switch, which can detect whether a detected object containing multiple metals exists in a specific range. The induction type proximity switch includes: an oscillation switch of which the amplitude is attenuated due to the proximity of the detected object containing metal, so as to detect the excessive proximity of the detected object; a detection circuit for detecting the amplitude of a high frequency generated by the oscillation of the oscillation circuit; an operation and comparison part for comparing the detected amplitude of the high frequency with the threshold set for the amplitude, i.e., a boundary as the excessive proximity, and outputting a detection signal of the excessive proximity when the detected amplitude is under the threshold; and a threshold setting part, for selecting a threshold corresponding to a designated metal type according to the designation on the metal type from the outside.

A resonant inductive sensing system includes a sensor resonator and an inductance-to-data converter (IDC) including an algorithmic control loop with operational and calibration phases. The resonator is characterized by a resonance state corresponding to a sensed condition. The IDC includes a negative impedance stage and a loop control stage. During the operation phase, the negative impedance stage drives the resonator with a selected (controlled) negative impedance. The loop control stage includes detection circuitry that detects resonance state, and range comparison circuitry that generates an out-of-range signal when the detected resonance state is not within a pre-defined range of resonance states. Algorithmic control circuitry is responsive to the out-of-range signal to transition the IDC to operation in the calibration phase, including determining an adjusted negative impedance corresponding to a resonance state within the pre-defined range of resonance states, and generating a negative impedance control signal based on the adjusted negative impedance.

The invention relates to an oscillator comprising a resonant circuit having at least one inductor and one capacitor and having a feedback amplifier, wherein there is at least one trimming resistor in a feedback circuit of the amplifier. The oscillator is characterized in that there is an electronic switching device for alternately connecting and disconnecting the trimming resistor, in that a trimming circuit is formed by the trimming resistor and the electronic switching device, in that there is a drive device for driving the electronic switching device, in that the electronic switching device, together with the drive device, is designed to alternately connect and disconnect the trimming resistor in a switching sequence, and in that an average time value of the electrical resistor of the trimming circuit, which is active in an oscillator mode, is defined by the switching sequence.

An electromagnetic encoding switch and a method for calculating rotation information of a runner. The electromagnetic encoding switch (10) comprises: a runner assembly (11), wherein the runner assembly (11) comprises an LC resonant circuit (111), the LC resonant circuit (111) comprising an inductor L and a capacitor C connected to the inductor L, the inductor L having a magnetic core, and the inductor L being used for receiving and transmitting electromagnetic waves; a runner (112), the LC resonant circuit (111) being disposed on the runner (112); a transceiver unit (12), the transceiver unit (12) comprising an antenna (121) disposed below the runner (112) and used for transmitting electromagnetic waves at a preset frequency in a transmitting period, so that the LC resonant circuit (111) receives energy in the transmitting period; and an antenna selection switch (122) connected to the antenna (121). The electromagnetic encoding switch (10) has no mechanical noise and is low-cost.

The present invention provides a proximity switch, which can detect whether a detected object containing multiple metals exists in a specific range. The induction type proximity switch includes: an oscillation switch of which the amplitude is attenuated due to the proximity of the detected object containing metal, so as to detect the excessive proximity of the detected object; a detection circuit for detecting the amplitude of a high frequency generated by the oscillation of the oscillation circuit; an operation and comparison part for comparing the detected amplitude of the high frequency with the threshold set for the amplitude, i.e., a boundary as the excessive proximity, and outputting a detection signal of the excessive proximity when the detected amplitude is under the threshold; and a threshold setting part, for selecting a threshold corresponding to a designated metal type according to the designation on the metal type from the outside.