The waveform generator (10) comprises a switch (13). The waveform generator (10) comprises a transformer (15) having a primary side circuit and a secondary side circuit. The primary side circuit has a first terminal arranged to be conductively coupled to a DC voltage source, and a second terminal conductively coupled to the switch (13). The waveform generator (10) further comprises a controller (11) arranged to supply a drive signal to the switch for switching the switch between on and off states. The controller (11) is arranged to adjust the frequency of the drive signal so as to control at least one of the peak voltage and the duty cycle of a waveform generated by the waveform generator (10). The frequency of the drive signal may be adjusted as the voltage level of the DC voltage source remains constant. The frequency of the drive signal may be adjusted in response to a change in the voltage level of the DC voltage source.

A circuit device includes an oscillation circuit. The oscillation circuit includes a first variable capacitance circuit whose capacitance change characteristic with respect to a capacitance control voltage is a positive characteristic and a second variable capacitance circuit whose capacitance change characteristic with respect to the capacitance control voltage is a negative characteristic, and oscillates a resonator. The circuit device further includes a switch circuit. The switch circuit receives a first input voltage at a first input terminal thereof, receives a second input voltage at a second input terminal thereof, outputs a first output voltage selected from a plurality of voltages including the first input voltage and the second input voltage to a first output terminal thereof to which the first variable capacitance circuit is electrically coupled, and outputs a second output voltage selected from the plurality of voltages to a second output terminal thereof to which the second variable capacitance circuit is electrically coupled.

The invention relates to a resonator circuit, the resonator circuit comprising a transformer comprising a primary winding and a secondary winding, wherein the primary winding is inductively coupled with the secondary winding, a primary capacitor being connected to the primary winding, the primary capacitor and the primary winding forming a primary circuit, and a secondary capacitor being connected to the secondary winding, the secondary capacitor and the secondary winding forming a secondary circuit, wherein the resonator circuit has a common mode resonance frequency at an excitation of the primary circuit in a common mode, wherein the resonator circuit has a differential mode resonance frequency at an excitation of the primary circuit in a differential mode, and wherein the common mode resonance frequency is different from the differential mode resonance frequency.

A variable capacitor circuit includes a capacitor block including a first varactor element comprising a first transistor having a first size, a second varactor element comprising a second transistor having a second size different from the first size, a first terminal commonly connected to a source and a drain of the first transistor, a second terminal commonly connected to a source and a drain of the second transistor, and an RC circuit connected to a gate of the first transistor and a gate of the second transistor.

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.

An oscillator circuit has a reconfigurable oscillator amplifier. The reconfigurable oscillator amplifier is used to be coupled to a resonant circuit in parallel. The reconfigurable oscillator amplifier supports different circuit configurations for different operation modes, respectively. The reconfigurable oscillator amplifier has at least one circuit component shared by the different circuit configurations. The reconfigurable oscillator amplifier employs one of the different circuit configurations under one of the different operation modes.

Embodiments of the present disclosure may provide a circuit comprising a tank circuit. The tank circuit may include an inductor having a pair of terminals, a first pair of transistors, and a first pair of capacitors. Each transistor may be coupled between a respective terminal of the inductor and a reference voltage along a source-to-drain path of the transistor. Each capacitor may be provided in a signal path between an inductor terminal coupled to a respective first transistor in the first pair and a gate of a second transistor in the first pair.

An apparatus includes an oscillation ring comprising N oscillators, where N is an even integer that is greater than 3, the N oscillators connected in series in a loop by N connection nodes, each oscillator of the N oscillators comprising a pair of cross-coupled inverting amplifiers. The apparatus also includes N inductors arranged in a star configuration such that each inductor of the N inductors connects to a corresponding connection node of the oscillation ring and a common connection node of the star configuration. The apparatus may also include N capacitor banks. Each of the N capacitor banks may include a plurality of activation switches for loading a corresponding oscillator with capacitance. A method includes providing the above apparatus and activating selected activation switches to adjust an oscillation frequency for the oscillation ring toward a desired value.

A variable capacitor circuit includes a capacitor block including a first varactor element comprising a first transistor having a first size, a second varactor element comprising a second transistor having a second size different from the first size, a first terminal commonly connected to a source and a drain of the first transistor, a second terminal commonly connected to a source and a drain of the second transistor, and an RC circuit connected to a gate of the first transistor and a gate of the second transistor.

The embodiments of the invention relate to a radio frequency oscillator, the radio frequency oscillator comprising a resonator circuit 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 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 configured to excite the resonator circuit in the common mode to obtain a common mode oscillator signal oscillating at the common mode resonance frequency.