The present application relates to a differential Colpitts voltage-controlled oscillator (VCO) circuit, which comprises a pair of transistors with control terminals biased by a common biasing voltage and a pair of couplers arranged to cross-couple corrector/drain of the transistors and the base/gate of the differential transistors. The pair of couplers have a coupling factor k.sub.c, which used to enhance the transconductance of the transistor pair, therefore can be used for power consumption reduction and phase noise minimalization.

A voltage controlled oscillator includes a series resonant circuit having a resonance frequency and an active voltage driving device coupled to the series resonant circuit. The active voltage driving device provides a driving voltage and has an output negative resistance in an operative voltage range at the resonance frequency. The active voltage driving device includes a cross-coupled differential pair having voltage supply terminals providing the driving voltage. The series resonant circuit is coupled between the voltage supply terminals of the cross-coupled differential pair.

The present application relates to a differential oscillator circuit. The differential oscillator circuit comprises a pair of transistors with control terminals biased by a common biasing voltage. The differential oscillator circuit further comprises a transformer having a primary coil coupled between first current terminals of the transistors and a secondary coil coupled in a closed series circuit with two varactors, which are arranged for being tuned by a first common tuning voltage. The differential oscillator circuit further comprises a series circuit comprising two further varactors coupled in series to second current terminals of the transistors. The two further varactors are arranged for being tuned by a second common tuning voltage.

Techniques are described for using valley detection for supply voltage modulation in power amplifier circuits. Embodiments operate in context of a power amplifier circuit configured to be driven by a supply voltage generated by a supply modulator and to receive an amplitude-modulated (AM) signal at its input. The output of the power amplifier circuit can be fed to a valley detector that can detect a valley level corresponding to the bottom of the envelope of the AM signal. The detected valley level can be fed back to the supply modulator and compared to a constant reference. In response to the comparison, the supply modulator can vary the supply voltage to the power amplifier circuit in a manner that effectively tracking the envelope of the power amplifier circuit's output signal, thereby effectively seeking a flat valley for the output signal's envelope.

A wireless communication apparatus includes an oscillator circuit configured to generate an oscillation signal corresponding to an oscillation frequency determined by an antenna, and a bias generator circuit configured to reconfigure an operation region mode of a transistor included in the oscillator circuit by adjusting a bias signal in response to an enable signal.

An inductor is disclosed that includes an arrangement of lobes, each of the lobes in the arrangement of lobes including a generator, the arrangement of lobes interconnected such that, when currents are provided by each generator in the arrangement of lobes, each lobe in the arrangement of lobes produces a magnetic field with a defined polarity relative to the arrangement of lobes. When the arrangement of lobes are appropriately interconnected, the magnetic field from the arrangement of lobes can be canceled.

In a PLL circuit, a multi-band control oscillator includes multiple bands gradually increasing or decreasing a frequency in accordance with a control signal and being separated from each other, is capable of selectively switching one band among the multiple bands, and generates a signal of a frequency corresponding to the control signal in the band that is switched as a reference signal. A band setting unit sets the band of the multi-band control oscillator. The band setting unit sets the band for a present or subsequent time after a control command generator finishes outputting the control command to gradually increase or decrease from a previous start frequency to a previous stop frequency and before the control command generator starts outputting the control command to gradually increase or decrease from a present start frequency.

Certain aspects of the disclosure are directed to electrostatic discharge protection of an integrated circuit clock. According to a specific example, circuitry includes a direct-current power supply, a voltage-controlled oscillation (VCO) circuit, an electrostatic protection circuit, and a voltage regulator. The VCO circuit has an oscillation frequency and includes an amplification circuit and capacitance circuitry. The electrostatic protection circuit is arranged to connect power to the VCO circuit while reducing variation in the oscillation frequency of the VCO circuit resulting from electrostatic energy. The voltage regulator is connected between the direct-current power supply and a power supply connection at which the direct-current power is connected to the VCO, and is configured to mitigate an imbalance of electric charges from adversely altering a tuning capacitance of the VCO established by the capacitance circuitry.

The present disclosure describes aspects of a switchable inductor network for wideband circuits. In some aspects, the switchable inductor network provides selectable inductance. The switchable inductor network includes a first coil and a second coil that includes a first inductive segment and a second inductive segment. Connection points of the second coil connect the second coil across a portion of the first coil. The switchable inductor network also includes a switch connected between the first inductive segment and the second inductive segment of the second coil. The switch is configured to change the selectable inductance of the switchable inductor network by selectively coupling the first inductive segment to the second inductive segment of the second coil in response to a control signal.

According to some embodiments, an integrated circuit device is disclosed. The integrated circuit device include at least one inductor having at least one turn, a magnetic coupling ring positioned adjacent to the at least one inductor, the magnetic coupling ring comprising at least two magnetic coupling turns, the at least two magnetic coupling turns are disposed adjacent to the at least one turn to enable magnetic coupling between the at least two magnetic coupling turns and the at least one turn The integrated circuit device also includes a power electrode and a ground electrode, wherein the power electrode and the ground electrode are coupled to the at least one inductor and the magnetic coupling ring to provide a first current in the at least one inductor having a direction opposite to a second current in the magnetic coupling ring to cancel at least a portion of a magnetic field generated by the at least one inductor.