One inductor and another inductor are magnetically coupled to each other. A variable current source controls the current flowing in the one inductor. By controlling the current flowing in the one inductor, the inductance value of the other inductor is made variable.

An oscillator circuit includes an amplifier including a first transconductance amplifier and a second transconductance amplifier; and a resonator including a capacitor element and an inductor element. The capacitor element includes a first capacitor and a second capacitor, the inductor element includes a tapped inductor, the tapped inductor includes a first segment of inductor and a second segment of inductor, and the first segment of inductor and the second segment of inductor are coupled using the first capacitor. The first segment of inductor includes a first terminal and a second terminal coupled to an input terminal and an output terminal of the first transconductance amplifier respectively. The second segment of inductor includes a third terminal and a fourth terminal coupled to an input terminal and an output terminal of the second transconductance amplifier, respectively.

An oscillator circuit includes an amplifier including a first transconductance amplifier and a second transconductance amplifier; and a resonator including a capacitor element and an inductor element. The capacitor element includes a first capacitor and a second capacitor, the inductor element includes a tapped inductor, the tapped inductor includes a first segment of inductor and a second segment of inductor, and the first segment of inductor and the second segment of inductor are coupled using the first capacitor. The first segment of inductor includes a first terminal and a second terminal coupled to an input terminal and an output terminal of the first transconductance amplifier respectively. The second segment of inductor includes a third terminal and a fourth terminal coupled to an input terminal and an output terminal of the second transconductance amplifier, respectively.

A voltage-controlled oscillator may include an inductor. The inductor may include a first coil coupled to an electronic component. The inductor may include a first coil coupled to the first circuit component, a second coil coupled to the first circuit component via a junction and being in parallel with the first coil, and a shared circuit path coupled to the second circuit component, the first coil, and the second coil, the shared circuit path overlapping the junction. The inductor may be configured to reduce phase noise generated by the electronic component.

A voltage-controlled oscillator may include an inductor. The inductor may include a first coil coupled to an electronic component. The inductor may include a first coil coupled to the first circuit component, a second coil coupled to the first circuit component via a junction and being in parallel with the first coil, and a shared circuit path coupled to the second circuit component, the first coil, and the second coil, the shared circuit path overlapping the junction. The inductor may be configured to reduce phase noise generated by the electronic component.

This application provides an oscillator circuit. The oscillator circuit includes: an amplifier, including a first transconductance amplifier, and a second transconductance amplifier; and a resonator, including a capacitor element and an inductor element. The capacitor element includes a first capacitor and a second capacitor, the inductor element includes a tapped inductor, the tapped inductor includes a first segment of inductor and a second segment of inductor, and the first segment of inductor and the second segment of inductor are coupled by using the first capacitor. The first segment of inductor includes a first terminal and a second terminal coupled to an input terminal and an output terminal of the first transconductance amplifier respectively. The second segment of inductor includes a third terminal and a fourth terminal coupled to an input terminal and an output terminal of the second transconductance amplifier respectively.

This application provides an oscillator circuit. The oscillator circuit includes: an amplifier, including a first transconductance amplifier, and a second transconductance amplifier; and a resonator, including a capacitor element and an inductor element. The capacitor element includes a first capacitor and a second capacitor, the inductor element includes a tapped inductor, the tapped inductor includes a first segment of inductor and a second segment of inductor, and the first segment of inductor and the second segment of inductor are coupled by using the first capacitor. The first segment of inductor includes a first terminal and a second terminal coupled to an input terminal and an output terminal of the first transconductance amplifier respectively. The second segment of inductor includes a third terminal and a fourth terminal coupled to an input terminal and an output terminal of the second transconductance amplifier respectively.

A two-wire displacement sensor device includes an LC oscillation circuit including a coil whose inductance changes in accordance with a displacement amount of an object and an oscillation unit provided with capacitors and amplifying elements; and an interface unit serving as a signal output unit and a power supply input unit. The interface unit includes a constant current circuit that outputs at least two current values.

A two-wire displacement sensor device includes an LC oscillation circuit including a coil whose inductance changes in accordance with a displacement amount of an object and an oscillation unit provided with capacitors and amplifying elements; and an interface unit serving as a signal output unit and a power supply input unit. The interface unit includes a constant current circuit that outputs at least two current values.

Embodiments of the present application provide an apparatus for injecting energy into a crystal in a crystal oscillator, and a crystal oscillator. The apparatus includes: a crystal; a voltage-controlled oscillator configured to output an oscillation signal to the crystal; a ramp voltage generating circuit configured to generate a ramp voltage that changes over time; a first switch disposed between the ramp voltage generating circuit and the voltage-controlled oscillator; a first capacitor, where a first terminal of the first capacitor is connected to the first switch and the voltage-controlled oscillator, and a second terminal of the first capacitor is grounded; and a control circuit configured to control a status of the first switch according to a current through the crystal. Therefore, the apparatus can efficiently inject energy into the crystal.