A programmable variable capacitor includes a fixed varactor controlled by a control voltage connected in a first polarity and a plurality of contingent varactors conditionally controlled by the control voltage in accordance with a plurality of logical signals, respectively, each of said plurality of contingent varactors having: a first varactor controlled by a first voltage connected in the first polarity, a second varactor controlled by a second voltage connected in a second polarity, a first multiplexer configured to output the first voltage by selecting between a first DC (direct-current) voltage and the control voltage in accordance with a respective logical signal among said plurality of logical signals, and a second multiplexer configured to output the second voltage by selecting between a second DC voltage and a medium DC voltage in accordance with the respective logical signal.

A voltage controlled oscillator (VCO) has a VCO core and a tuning bank. The tuning bank includes first and second tuning capacitors. A main switch is coupled between the first and second tuning capacitors. The tuning bank also includes control switches that receive a control signal to selectively activate the tuning bank. The main switch receives a level-shifted control signal to activate the tuning bank.

The disclosure relates to a radio frequency oscillator. The radio frequency oscillator includes a resonator circuit being resonant at an excitation of the resonator circuit in a differential mode and at an excitation of the resonator circuit in a common mode. The resonator circuit has a differential mode resonance frequency at the excitation in the differential mode, and the resonator circuit has a common mode resonance frequency at the excitation in the common mode. A first excitation circuit is configured to excite the resonator circuit in the differential mode to obtain a differential mode oscillator signal oscillating at the differential mode resonance frequency, and a second excitation circuit is configured to excite the resonator circuit in the common mode to obtain a common mode oscillator signal oscillating at the common mode resonance frequency.

Techniques are described that enables controlling the TNULL characteristic of a self-compensated oscillator by controlling the magnitude and direction of the frequency deviation versus temperature, and thus, compensating the frequency deviation.

A variable-gain power amplifying technique includes generating, with a network of one or more reactive components included in an oscillator, a first oscillating signal, and outputting, via one or more taps included in the network of the reactive components, a second oscillating signal. The second oscillating signal has a magnitude that is proportional to and less than the first oscillating signal. The power amplifying technique further includes selecting one of the first and second oscillating signals to use for generating a power-amplified output signal, and amplifying the selected one of the first and second oscillating signals to generate the power-amplified output signal.

A resonator circuit includes a transformer comprising a primary winding and a secondary winding. The primary winding is inductively coupled with the secondary winding. A primary capacitor is connected to the primary winding. The primary capacitor and the primary winding form a primary circuit. A secondary capacitor is connected to the secondary winding. The secondary capacitor and the secondary winding form a secondary circuit. The resonator circuit has a common mode resonance frequency at an excitation of the primary circuit in a common mode. The resonator circuit has a differential mode resonance frequency at an excitation of the primary circuit in a differential mode. The common mode resonance frequency is different from the differential mode resonance frequency.

The invention relates to a radio frequency oscillator, the radio frequency oscillator comprising a resonator circuit being resonant at an excitation of the resonator circuit in a differential mode and at an excitation of the resonator circuit in a common mode, wherein the resonator circuit has a differential mode resonance frequency at the excitation in the differential mode, and wherein the resonator circuit has a common mode resonance frequency at the excitation in the common mode, a first excitation circuit being configured to excite the resonator circuit in the differential mode to obtain a differential mode oscillator signal oscillating at the differential mode resonance frequency, and a second excitation circuit being configured to excite the resonator circuit in the common mode to obtain a common mode oscillator signal oscillating at the common mode resonance frequency.

Oscillators and methods for realignment of an oscillator are provided. An oscillator includes an inductor having first and second terminals and a capacitor electrically coupled in parallel to the inductor at the first and second terminals. A first transistor of a first conductivity type is electrically coupled to the first terminal and a voltage source. The first transistor includes a gate configured to receive a first realignment signal. When the first realignment signal is in a realignment state, the first transistor is turned on and a voltage of the first terminal is increased from a low level to a high level in order to align a phase of a waveform of the oscillator.

An oscillator and a clock circuit are disclosed. In an oscillator (100), a tail inductor connected to a cross-coupled transistor includes at least two inductors connected in parallel. Therefore, an inductance of the tail inductor is less than an inductance of any one of the inductors. This can address a design difficulty that a tail inductor with a smaller inductance needs to be used as an operating frequency of a VCO increases. The oscillator (100) includes a first cross-coupled transistor (121) and a first tail inductor (111). The first tail inductor (111) includes at least two inductors connected in parallel. The first tail inductor (111) is coupled to a source of the first cross-coupled transistor (121). The source of the first cross-coupled transistor (121) is coupled to a power supply or a ground through the first tail inductor (111).

An electronic device may include a transceiver with mixer circuitry that up-converts or down-converts signals based on a voltage-controlled oscillator (VCO) signal. The transceiver circuitry may include first, second, third, and fourth VCOs. Each VCO may include a VCO core that receives a control voltage and an inductor coupled to the VCO core. Fixed linear capacitors may be coupled between the VCO cores. A switching network may be coupled between the VCOs. Control circuitry may place the VCO circuitry in one of four different operating modes and may switch between the operating modes to selectively control current direction in each of the inductors. The VCO circuitry may generate the VCO signal within a respective frequency range in each of the operating modes. The VCO circuitry may exhibit a relatively wide frequency range across all of the operating modes while introducing minimal phase noise to the system.