An oscillator circuit uses a comparator, and the oscillator circuit controls charge-discharge of the Miller capacitance between the gate and the drain of a MOSFET serving as an amplifier of the gain unit and the gate capacitance of the MOSFET, and enables the comparator output to follow a relatively high-frequency control signal that is input externally. The oscillator circuit uses a comparator having a differential unit and a gain unit. The oscillator circuit includes a charge-discharge control unit that connects to the output of the differential unit and is configured to control charge-discharge of the Miller capacitance between the gate and the drain of a MOSFET (N2) serving as an amplifier of the gain unit and the gate capacitance of the MOSFET, and an output control unit configured to control the output of the gain unit.

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.

A device includes a transformer that further includes a primary and a secondary windings. A switch is coupled to the primary winding, and this switch is controlled by the received digital input signal. An oscillator is further formed on the secondary winding where the oscillator oscillates in response to variations of the received input signal. A detector coupled to the oscillator will then detect the oscillations in response to the variations of the received input signal. Thereafter, the detector generates a digital output based on the detected oscillations.

Various embodiments of the invention relate to a Multi-Band Voltage Controlled Oscillator (VCO). The multi-band VCO features a coupled-inductor based resonator. The resonator comprises a primary path and a secondary path inductively coupled to the primary path. The primary path comprises multiple LC tuning stages coupled in series with each stage having an adjustable capacitor and a primary inductor inductively coupled to the secondary path. The secondary path comprises multiple secondary inductors inductively coupled to respective primary inductors in the primary path. Furthermore, the secondary path comprises a plurality of controllable switches which are controlled to switch ON or OFF simultaneously to engage/disengage the inductive coupling between the primary path and the secondary path. Incorporating multiple LC tuning stages lowers voltage swing across each tuning stages, thus minimizing phase noise caused by nonlinearity in the resonator.

According to one embodiment, there is provided a semiconductor integrated circuit including an oscillation circuit, a charge pump circuit, a smoothing circuit, and a negative feedback circuit. The charge pump circuit is arranged between each of a power supply input terminal and the oscillation circuit and a power supply output terminal. The smoothing circuit is arranged between the charge pump circuit and the power supply output terminal. The negative feedback circuit is arranged on a path returning from the smoothing circuit to the oscillation circuit. The smoothing circuit includes a first zero point generation circuit.

A technique for tuning a ladder-shaped inductor that achieves a finer tuning resolution by severing one or more shorts, skipping the severing of one or more shorts, and severing one or more subsequent shorts within the ladder-shaped inductor. This technique can be applied to a voltage-controlled oscillator using a differential or single-ended ladder-shaped inductor as part of the resonant circuit. Within an oscillator, such a technique provides for a more precise modulation of the effective inductance of the ladder-shaped inductor, which enables an improved tuning resolution of the operating frequency of the oscillator.

A voltage controlled oscillator (VCO) is disclosed to provide reduced phase noise at higher operating frequencies. A buffer-first VCO configured according to an embodiment includes multiple VCO core circuits configured to provide synchronously tuned oscillator signals. Each VCO core circuit is coupled to a summing node through a buffer circuit that generates uncorrelated phase noise such that the summing node provides a summation output of the oscillator signals with reduced phase noise. A multiplexer-less VCO configured according to an embodiment includes multiple buffer-first VCO circuits configured to provide oscillator signals covering a range of frequencies. Each buffer-first VCO circuit is controlled or selected by an enable signal. Buffer circuits are configured to select one of the buffer-first VCO circuits for coupling to a transmission line during a given time period based on the enable signal. The transmission line is terminated in a matched impedance at each end of the line.

A CMOS gain element is disclosed herein. Also disclosed herein are splitters, comprising the CMOS gain element, and local oscillator distribution circuitry comprising the splitters and the CMOS gain elements. Semiconductor devices comprising the local oscillator distribution circuitry may have smaller footprints and reduced power consumption relative to prior art devices.

A voltage-controlled oscillator (VCO) includes a first transistor cross-coupled with a second transistor, and a transformer-coupled band-pass filter (BPF) including a first transformer and a second transformer. The first transformer is configured to control a gate and a drain terminal of the first transistor, and the second transformer is configured to control a gate and a drain terminal of the second transistor.

A FET driving circuit includes: inputs into which a DC voltage is inputted; outputs connected to gate and source electrodes of a FET; a switch; a capacitance connected across the switch; and an LC resonance circuit connected in series with the switch across the inputs. A voltage generated across the switch during switching is outputted to drive the FET. The LC resonance circuit has a first connector connected to one input and a second connector connected to the switch, and is configured with a path including an inductance and a path including an inductance and a capacitance. An impedance between the first and second connectors has two resonant frequencies. The impedance has a local maximum at the lower resonant frequency, which is higher than a switching frequency, and a local minimum at the higher resonant frequency, which is around double the switching frequency.