Abstract: A frequency multiplier includes a first ring oscillator, a second ring oscillator that is turned on complementarily to the first ring oscillator, a combining circuit that combines a first output signal of the first ring oscillator and a second output signal of the second ring oscillator to generate a final output signal, and a calibration circuit that corrects a discontinuous pulse included in the final output signal based on feedback of the final output signal.

Abstract: A clock generator includes a phase controller configured to generate phase control information in response to comparing a phase of an input clock signal against a phase of a division clock signal, and an oscillator configured to generate a plurality of oscillation signals at an equivalent output frequency but different phases, in response to the phase control information and duty control information. A duty cycle converter is provided, which is configured to generate a plurality of output clock signals at the output frequency by adjusting duty cycles of the plurality of oscillation signals, such that the plurality of output clock signals have duty cycles smaller than the duty cycles of the plurality of oscillation signals. A clock divider is provided, which is configured to generate the division clock signal by dividing the output frequency of one of the plurality of output clock signals, such that the division clock signal has a division frequency smaller than the output frequency.

Abstract: Proposed are an ultra-low jitter low-power phase-locked loop using a power-gating injection-locked frequency multiplier-based phase detector (PG-ILFM PD) and an operating method thereof. The proposed PG-ILFM PD includes a replica voltage controlled oscillator (R-VCO) configured to cut off the power supply of the R-VCO repeatedly based on a reference signal SREF and a fundamental sampling phase detector (FSPD) configured to receive an output signal SILFM of the R-VCO as a reference signal for sampling and detect a phase error of a main voltage controlled oscillator (M-VCO).

Abstract: Proposed are an ultra-low jitter low-power phase-locked loop using a power-gating injection-locked frequency multiplier-based phase detector (PG-ILFM PD) and an operating method thereof. The proposed PG-ILFM PD includes a replica voltage controlled oscillator (R-VCO) configured to cut off the power supply of the R-VCO repeatedly based on a reference signal SREF and a fundamental sampling phase detector (FSPD) configured to receive an output signal SILFM of the R-VCO as a reference signal for sampling and detect a phase error of a main voltage controlled oscillator (M-VCO).

Abstract: Disclosed is an integrated circuit, which includes a DTC block including DTCs, receiving a first reference signal and a first division signal, and outputting a second reference signal and a second division signal based on the first reference signal, the first division signal, and control codes, a TDC comparing phases of the second reference signal and the second division signal and outputting a comparison signal, a digital loop filter filtering the comparison signal, an oscillator generating an output signal based on the filtered comparison signal, a delta-sigma modulator outputting a first signal and a quantized noise signal based on first and second division ratio signals, a divider dividing a frequency of the output signal based on the first signal and outputting the first division signal, and a probability modulator generating the control codes based on the quantized noise signal. Probability density functions of the control codes are time-invariant.

Abstract: Disclosed is an integrated circuit, which includes a DTC block including DTCs, receiving a first reference signal and a first division signal, and outputting a second reference signal and a second division signal based on the first reference signal, the first division signal, and control codes, a TDC comparing phases of the second reference signal and the second division signal and outputting a comparison signal, a digital loop filter filtering the comparison signal, an oscillator generating an output signal based on the filtered comparison signal, a delta-sigma modulator outputting a first signal and a quantized noise signal based on first and second division ratio signals, a divider dividing a frequency of the output signal based on the first signal and outputting the first division signal, and a probability modulator generating the control codes based on the quantized noise signal. Probability density functions of the control codes are time-invariant.

Abstract: A tunable oscillator circuit is disclosed. The tunable oscillator circuit includes an inductor/capacitor (LC) tank circuit comprising a primary inductor coupled in parallel with a first capacitor bank. The LC tank resonates to produce an oscillating voltage at a frequency. The tunable oscillator circuit also includes a 90 degree phase shift buffer coupled to the LC tank and a transconductor. The transconductor is coupled to the 90 degree phase shift buffer and a secondary inductor. The tunable oscillator circuit also includes a secondary inductor that is inductively coupled to the primary inductor and receives a gain-scaled oscillating current from the transconductor. By changing the transconductance, the gain-scaled oscillating current in the secondary inductor will change, thus the effective primary inductance and the oscillation frequency can be tuned.

Abstract: Multi-mode oscillators supporting multiple modes and having different desirable characteristics (e.g., good phase noise or low power consumption) in different modes are disclosed. In an exemplary design, an apparatus includes first and second transistors of a first transistor type (e.g., NMOS transistors) and third and fourth transistors of a second transistor type (e.g., PMOS transistors) for a multi-mode oscillator. The third and fourth transistors are coupled (e.g., directly) to the first and second transistors. The first and second transistors are enabled in a first mode to provide signal gain for the oscillator and generate an oscillator signal in the first mode. The first to fourth transistors are enabled in a second mode to provide signal gain for the oscillator and generate the oscillator signal in the second mode. Different supply voltages may be provided at different supply nodes of the oscillator in the first and second modes.

Abstract: A tunable oscillator circuit is disclosed. The tunable oscillator circuit includes an inductor/capacitor (LC) tank circuit comprising a primary inductor coupled in parallel with a first capacitor bank. The LC tank resonates to produce an oscillating voltage at a frequency. The tunable oscillator circuit also includes a 90 degree phase shift buffer coupled to the LC tank and a transconductor. The transconductor is coupled to the 90 degree phase shift buffer and a secondary inductor. The tunable oscillator circuit also includes a secondary inductor that is inductively coupled to the primary inductor and receives a gain-scaled oscillating current from the transconductor. By changing the transconductance, the gain-scaled oscillating current in the secondary inductor will change, thus the effective primary inductance and the oscillation frequency can be tuned.

Abstract: Embodiments of the invention may provide for a frequency synthesizer capable to generate an output signal in which the frequency is a fractional portion of the reference frequency without a fractional divider. Based on mathematical relationship (“relatively prime”) between the reference frequency and other injection frequencies mixed with the output signal of a voltage controlled oscillator, the synthesizer is able to generate signals evenly spaced in the frequency domain like Fractional-N PLLs. The synthesizer may include an Integer-N PLL, a SSB mixer, frequency dividers, and frequency multipliers. A Integer-N PLL may include a Phase and Frequency Detector, a Charge Pump, a Loop Filter and a Dual Modulus Divider. By not requiring a fractional divider, the frequency synthesizer is able to avoid adopting any compensation circuits such as Sigma-Delta modulator to suppress fractional spurs. Therefore, the chip area, power consumption and complexity will be reduced considerably.