A voltage-controlled oscillator, including a voltage-controlled LC resonator including at least one first output node; an amplifier including at least one first dual-gate MOS transistor including first and second gates, coupling the first output node to a second node of application of a reference potential; and a regulation circuit capable of applying to the second gate of the first transistor a bias voltage variable according to the amplitude of the oscillations of a signal delivered on the first output node of the oscillator.

An oscillator circuit comprises a crystal oscillator arranged to generate an oscillation signal, a bias current generator arranged to supply a bias current to the crystal oscillator, and a feedback stage arranged to generate a feedback signal in response to an amplitude of the oscillation signal reaching an amplitude threshold. The bias current generator is arranged to: in response to a supply of power to the oscillator circuit being switched on, generate the bias current at an increasing level commencing from a first level; in response to the feedback signal, terminate the increasing; and during subsequent oscillation of the crystal oscillator, supply the bias current at a second level dependent on a final level of the bias current reached when the increasing is terminated.

An oscillator apparatus includes an oscillator core circuit. The oscillator core circuit includes an inverting transconductance amplifier, at least one first capacitor, at least one second capacitor, and a resonator. The at least one first capacitor is connected between an input of the inverting transconductance amplifier and a ground level. The at least one second capacitor is connected between an output of the inverting transconductance amplifier and the ground level. The resonator has a first port connected to the input of the inverting transconductance amplifier and a second port connected to the output of the inverting transconductance amplifier. The first port is decoupled from the second port.

A phase-locked loop circuit includes an oscillator, a frequency control device, the frequency control device generating a frequency control signal that controls a frequency of the oscillator, and a bias optimizer that monitors the frequency control device and generates a bias voltage for the oscillator, the oscillator includes a transfer function from bias voltage to frequency that is proportional to a transfer function from a low frequency noise component to frequency, the transfer function from bias voltage to frequency having a convex shape with a local minimum at which a sensitivity of the frequency to changes in the bias voltage is zero, and the bias voltage from the bias optimizer is set to the local minimum.

An oscillator circuit (100) comprises a crystal oscillator (10) arranged to generate an oscillation signal, a bias current generator (20) arranged to supply a bias current to the crystal oscillator (10), and a feedback stage (30) arranged to generate a feedback signal in response to an amplitude of the oscillation signal reaching an amplitude threshold. The bias current generator (20) is arranged to: in response to a supply of power to the oscillator circuit (100) being switched on, generate the bias current at an increasing level commencing from a first level; in response to the feedback signal, terminate the increasing; and during subsequent oscillation of the crystal oscillator (10), supply the bias current at a second level dependent on a final level of the bias current reached when the increasing is terminated.

Embodiments of methods and apparatuses may provide the capability to extend the tuning range of a VCO in a way that does not degrade VCO circuit performance. For example, the parasitic capacitance of semiconductor devices in the VCO circuit may be utilized to extend the tuning range of a VCO without significant degradation of VCO circuit performance. For example, in an embodiment, a method voltage-control of an oscillator may comprise receiving a first signal for control of a frequency of an output signal from the oscillator, deriving a second signal from the first signal, controlling the frequency of the output signal from the oscillator using the first signal, and extending a frequency range of the oscillator using the second signal.

A circuit device includes a drive circuit driving a resonator, an oscillation circuit having the resonator and a variable capacitance circuit coupled to an oscillation loop including the drive circuit, and a D/A converter circuit that performs D/A conversion on frequency control data and outputs a first voltage signal and a second voltage signal which are differential signals. The variable capacitance circuit includes a first variable capacitance capacitor, to one end of which the first voltage signal is input and, to the other end of which a first bias voltage is input and a second variable capacitance capacitor, to one end of which the second voltage signal is input and, to the other end of which a second bias voltage is input.

A decoder according to one embodiment of the invention includes a set of lines, a resonator circuit, a set of input leads for receiving input signals, and a set of switches for coupling some of the lines within the set of lines to the resonator circuit in response to the input signals while the other lines within the set of lines are at a first binary voltage. The lines are coupled to a set of pointer circuits. The pointer circuits perform logic functions on the signals on the lines when the resonating signal is at a second binary voltage opposite the first binary voltage to thereby decode the input signals. Because the lines are driven high and low by a resonator circuit, the decoder circuit power consumption is less than it would be if the lines were pulled up and down by a set of pullup and pulldown transistors.

A phase-locked loop circuit includes an oscillator, a frequency control device, the frequency control device generating a frequency control signal that controls a frequency of the oscillator, and a bias optimizer that monitors the frequency control device and generates a bias voltage for the oscillator, the oscillator includes a transfer function from bias voltage to frequency that is proportional to a transfer function from a low frequency noise component to frequency, the transfer function from bias voltage to frequency having a convex shape with a local minimum at which a sensitivity of the frequency to changes in the bias voltage is zero, and the bias voltage from the bias optimizer is set to the local minimum.

A compensation module, an oscillation circuit and associated compensation method for reducing an oscillation frequency variation in an output oscillation signal of a voltage-controlled oscillator (VCO) core are provided. The compensation module includes a compensation circuit and a polarity selection circuit. The compensation circuit has a capacitance value related to voltages of a first and a second receiving terminals. The oscillation frequency variation is changed with the capacitance value. The polarity selection circuit conducts a periodic regulated signal to one of the first receiving terminal and the second receiving terminal. The polarity selection circuit conducts a filtered bias signal to the other of the first receiving terminal and the second receiving terminal. The periodic regulated signal is sensitive to a regulated voltage variation, and the filtered bias signal is insensitive to the regulated voltage variation.