A circuit device includes a phase comparison circuit that performs phase comparison between a reference clock signal and a feedback clock signal, a control voltage generation circuit that generates a control voltage, a voltage controlled oscillation circuit that generates a clock signal, a dividing circuit that divides the clock signal and outputs the feedback clock signal, a processing circuit that sets a division ratio of the dividing circuit, a first register in which slope information of a waveform signal for spreading the frequency of the clock signal is set, and a second register in which amplitude information of the waveform signal is set. The processing circuit generates a waveform signal value based on the slope information and the amplitude information set in the first and second registers, and outputs division ratio data based on the waveform signal value and the division ratio setting value to the dividing circuit.

A method comprises: using a plurality of gain stages cascaded in a ring topology to form a ring oscillator configured to output an oscillation signal; controlling a supply voltage of said ring oscillator using a low-speed DAC (digital-to-analog converter) in accordance with a coarse control word; providing a capacitive load at an inter-stage node of said ring oscillator using a varactor array controlled by a control voltage array; establishing said control voltage array using a high-speed DAC array in accordance with a fine control word; adjusting the coarse control word upon a start-up to make an oscillation frequency of said oscillation signal approximately equal to target value; and adjusting the fine control word in a closed loop manner in accordance with a detection of a timing error of said oscillation signal.

A method comprises: using a plurality of gain stages cascaded in a ring topology to form a ring oscillator configured to output an oscillation signal; controlling a supply voltage of said ring oscillator using a low-speed DAC (digital-to-analog converter) in accordance with a coarse control word; providing a capacitive load at an inter-stage node of said ring oscillator using a varactor array controlled by a control voltage array; establishing said control voltage array using a high-speed DAC array in accordance with a fine control word; adjusting the coarse control word upon a start-up to make an oscillation frequency of said oscillation signal approximately equal to target value; and adjusting the fine control word in a closed loop manner in accordance with a detection of a timing error of said oscillation signal.

Dynamic voltage frequency scaling to transition to a target clock frequency and associated target voltage is provided. Dynamic voltage frequency scaling to a different clock frequency is performed by gradually changing the clock frequency using discrete variable-size steps, while dynamically switching to faster or slower reference clock frequencies as appropriate to harmonize the frequency trajectory with system requirements.

Dynamic voltage frequency scaling to transition to a target clock frequency and associated target voltage is provided. Dynamic voltage frequency scaling to a different clock frequency is performed by gradually changing the clock frequency using discrete variable-size steps, while dynamically switching to faster or slower reference clock frequencies as appropriate to harmonize the frequency trajectory with system requirements.

A clock distribution circuit may include a data clock generation circuit configured to be input a power source voltage and configured to generate an internal clock signal according to an external clock signal; and a global distribution circuit includes a first circuit and a second circuit coupled to a global line, configured to be input a power source voltage and configured to receive the internal clock signal through the first circuit and distribute the internal clock signal to an exterior of the clock distribution circuit through the second circuit, wherein a first bias voltage provided to the first circuit and a second bias voltage provided to the second circuit are controlled independently of each other.

A clock distribution circuit may include a data clock generation circuit configured to be input a power source voltage and configured to generate an internal clock signal according to an external clock signal; and a global distribution circuit includes a first circuit and a second circuit coupled to a global line, configured to be input a power source voltage and configured to receive the internal clock signal through the first circuit and distribute the internal clock signal to an exterior of the clock distribution circuit through the second circuit, wherein a first bias voltage provided to the first circuit and a second bias voltage provided to the second circuit are controlled independently of each other.

A method for a radar device is described. According to one example implementation, the method comprises generating an RF signal using a voltage-controlled oscillator (VCO), wherein the frequency of the RF signal depends on a first tuning voltage and a second tuning voltage. The method also comprises setting the second tuning voltage using a phase-locked loop coupled to the VCO, with the result that the frequency of the RF signal corresponds to a desired frequency. The first tuning voltage is changed in such a manner that the second tuning voltage set by the phase-locked loop corresponds approximately to a predefined value. Another example implementation relates to a method for a radar device comprising: generating an RF signal using a VCO, wherein the frequency of the RF signal depends on a tuning voltage, setting the tuning voltage using a phase-locked loop coupled to the VCO, with the result that the frequency of the RF signal corresponds to a desired frequency, and determining a differential VCO gain of the VCO. The bandwidth of the phase-locked loop is set on the basis of the determined VCO gain.

A method for a radar device is described. According to one example implementation, the method comprises generating an RF signal using a voltage-controlled oscillator (VCO), wherein the frequency of the RF signal depends on a first tuning voltage and a second tuning voltage. The method also comprises setting the second tuning voltage using a phase-locked loop coupled to the VCO, with the result that the frequency of the RF signal corresponds to a desired frequency. The first tuning voltage is changed in such a manner that the second tuning voltage set by the phase-locked loop corresponds approximately to a predefined value. Another example implementation relates to a method for a radar device comprising: generating an RF signal using a VCO, wherein the frequency of the RF signal depends on a tuning voltage, setting the tuning voltage using a phase-locked loop coupled to the VCO, with the result that the frequency of the RF signal corresponds to a desired frequency, and determining a differential VCO gain of the VCO. The bandwidth of the phase-locked loop is set on the basis of the determined VCO gain.

An apparatus includes a digital frequency synthesizer (DFS). The DFS includes a time-to-digital converter (TDC) to provide an output signal that represents a phase difference between a reference signal and a feedback signal. The DFS further includes a scaling circuit, which has an adaptively changed gain, to provide a scaled residue signal used to cancel an effect of the residue signal in the DFS.