The invention generally relates to a field regulator, particularly a field regulator for a resonant circuit, a transmitter including such a field regulator, a proximity detection system including such a transmitter, and a method of regulating a resonant circuit. In one aspect the invention provides a field regulator for a resonant circuit, the resonant circuit including an inductor coil around a core, the field regulator including a DC bias circuit configured to apply a DC bias current to the inductor coil for regulating an electromagnetic field generated by the inductor. The DC bias circuit can be used to selectively change the inductance of the inductor in the resonant circuit so as to maintain a consistent field strength in a changing environment, particularly to take into account the presence of large metal bodies which might otherwise adversely impact on operation. In particular, the DC bias current may be used to selectively change the natural frequency of the resonant circuit so as to shift the resonant circuit towards a desired resonance point.

An electronic device may include a conductor sensing assembly for sensing movement of a conductor, for example, in order to provide an input assembly that may be operative to detect a user's manipulation of a distance between the conductor and a portion of the conductor sensing assembly for controlling a functionality of the device. The conductor sensing assembly may include an oscillator that may produce oscillations that decay at different rates dependent upon a variable distance between a component of the conductor sensing assembly and a conductor of the input assembly. As the decay rate may be dependent on or otherwise correlate with the magnitude of a distance between the oscillator and a conductor, detection of the decay rate of the oscillator may enable determination of a state of a button input assembly that includes a conductor operative to be movable by a user with respect to the oscillator.

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.

In one embodiment, an inductive/LC sensor device includes: an energy storage device for accumulating excitation energy, an LC sensor configured to oscillate using energy accumulated in the energy storage device and transferred to the LC sensor, an energy detector for detecting the energy accumulated in the energy storage device reaching a charge threshold, and at least one switch coupled with the energy detector for terminating accumulating excitation energy in the energy storage device when the charge threshold is detected having been reached by the energy detector.

In one embodiment, an inductive/LC sensor device includes: an energy storage device for accumulating excitation energy, an LC sensor configured to oscillate using energy accumulated in the energy storage device and transferred to the LC sensor, an energy detector for detecting the energy accumulated in the energy storage device reaching a charge threshold, and at least one switch coupled with the energy detector for terminating accumulating excitation energy in the energy storage device when the charge threshold is detected having been reached by the energy detector.

To ensure omnidirectional visibility of a proximity sensor with high luminance using a single light emitting element. A proximity sensor (1) includes a substrate (14) on which a control unit (20) is formed and in which a normal direction of the substrate is perpendicular to an axial direction of a coil section (13), a light emitting element (15) which emits light in the axial direction on the substrate, a light diffusion section (16a) which diffuses emitted light in a direction other than the axial direction, and a light guide section (16b) which guides diffused light to a display section (21) on a side surface.

A wearable device comprises an exteriorly positioned first electrode and a reporting capacitor. The first electrode forms a first side of the reporting capacitor, and a second side of the reporting capacitor is formed by skin of a user when the wearable device is worn. An oscillator is configured to output a signal to drive the first electrode at a first frequency. The oscillator is configured such that changes in capacitance at the reporting capacitor adjust the signal output by the oscillator from the first frequency to a second frequency. A frequency-to-voltage converter is configured to generate a voltage representation of the second frequency. A controller determines a change between the first frequency and the second frequency based on the voltage representation and indicates an amount of movement of skin of the user relative to the first electrode based on the determined frequency change.

A proximity sensor includes an active sensor, a passive target, and a measurement circuit. The active sensor includes an active resonant tank circuit that includes an excitation source, a first capacitor, and a first inductor. The passive target includes a passive resonant tank circuit that includes a second capacitor and a second inductor, where magnetic coupling between the first inductor and the second inductor varies as a function of physical displacement of the first inductor and the second inductor with respect to one another. The measurement circuit is configured to measure a coupled resonant frequency response in the active resonant tank circuit and provide a measured distance output based on the coupled resonant frequency response.

A target device for use with a switch device of a proximity switch has a wireless receiver means (6) for detecting and receiving a first pulsating signal (A) with a first carrier frequency (f1) from a nearby transmitter module (5), demodulating (6, 7) the received signal, and if a superimposed digital signal is present, inverting (9, 10, C4, and Q1) the superimposed received digital signal or, if the superimposed digital signal is absent, passing the existing energy through (10). The target device also has a wireless transmitter means (12) for modulating and sending the inverted pulse train if this exists by the second carrier frequency (f2) to the receiver switch unit (13). Additionally, the target comprises functionality to transmit the carrier frequency (f2) continuous and unmodulated where a continuous and unmodulated carrier frequency (f1) is present. However, upon existence of the pulsating signal only one of the receiver (6) and the transmitter (12) receives or transmits a signal at a given time.

A method for measuring a physical quantity with a, particularly inductive, sensor element and for providing a sensor output depending on the physical quantity. The sensor element is part of a resonant circuit whose attenuation depends on the physical quantity being measured. The resonant circuit is excited to generate a periodic oscillation signal, the amplitude of which depends on the attenuation. The oscillation signal is compared with a comparator threshold value in a comparator to produce a periodic comparator signal with a duty cycle depending on the comparator threshold value. The comparator threshold value is set to be different from a mean value of the oscillation signal so that a duty cycle different from 50% is achieved. The sensor output is output depending on the duty cycle of the comparator signal.