Disclosed is a frequency dividing circuit, a frequency dividing method and a phase locked loop. The frequency dividing circuit comprises: a clock selection unit outputting a first clock signal, select a second clock signal lagging behind the first clock signal by (½-1/M) of one phase; an integer frequency dividing unit performing frequency division on the first clock signal to provide a frequency-divided clock signal; a trigger unit triggering the frequency-divided clock signal according to the second clock signal to obtain a modulation clock signal; a switching signal unit providing a switching signal according to the modulation clock signal and a preset target output frequency. The clock selection unit selects and further outputs a third clock signal as the first clock signal according to the target phase selection information, to adjust the frequency of the frequency-divided clock signal, reduce noise and improve loop bandwidth of the phase locked loop.

A signal generating electric circuit, a signal generating method, a digit-to-time converting electric circuit and a digit-to-time converting method. The signal generating electric circuit includes: a first generating electric circuit configured for, based on a first frequency control word and a reference time unit, generating a periodic first output signal; and a second generating electric circuit configured for, based on a second frequency control word and the reference time unit, generating a periodic second output signal. The first frequency control word includes a first integer part and a first fractional part, the second frequency control word includes a second integer part and a second fractional part, the first integer part is equal to the second integer part, the first fractional part is not zero, the second fractional part is zero, and a period of the first output signal and a period of the second output signal are not equal.

A phase locked loop includes a phase detector outputting a first signal corresponding to a phase difference of a reference frequency signal and a division frequency signal, a charge pump amplifying a first signal to output a second signal, a loop filter filtering the second signal to output a third signal, a voltage-to-current converter receiving the third signal and outputting a fourth signal, a digital-to-analog converter outputting a fifth signal based on the fourth signal and a digital compensation signal, an oscillator outputting an output frequency signal having a frequency corresponding to the fifth signal, a divider dividing the frequency of the output frequency signal to output the division frequency signal and a compensation frequency signal, and an automatic frequency calibrator compensating for the voltage-to-current converter based on a difference between a frequency of the compensation frequency signal and a frequency of a reference frequency signal.

A digital-to-time converter (DTC)-based open loop frequency synthesis and calibration circuit may be used to provide a precise clock signal. The DTC calibration circuit may include a DTC to generate a DTC clock signal based on a received input clock frequency and a received initial digital input code, a phase-lock loop (PLL) to generate a PLL clock signal based on a received PLL input, a binary phase-detector (PD) to generate a PD output based on a comparison between the DTC clock signal and the PLL clock signal, a plurality of calibration bins to generate a signed accumulated PD portion based on the PD output, and an adder to generate a calibrated DTC input code based on a combination of the signed accumulated PD portion and a subsequent digital input code, where the DTC generates a calibrated clock signal based on the calibrated DTC input code.

An apparatus includes a power converter circuit configured to generate a voltage level on a regulated power supply node using a clock signal, and a clock generation circuit configured to dither a frequency of the clock signal. To transition from a first frequency to a second frequency, the clock generation circuit is configured to change, during an initial transition period, the clock signal between the first and second frequencies such that a particular percentage of clock pulses have the second frequency. During one or more intermediate transition periods, the clock generation circuit is configured to change the clock signal between the first and second frequencies such that a percentage of clock pulses having the second frequency increases relative to a prior transition period. During a final transition period of the series, the clock generation circuit is configured to set the frequency of the clock signal to the second frequency.

Systems and methods provide a fractional signal from a delta sigma modulator to a summer, a combination of an integer value and the fractional signal to a divider, and a divided clock signal from the divider in response to the combination and the input clock signal. The systems and methods also delay the divided clock signal in response to a truncation phase error and gain calibration factor from a calibration unit to provide an output clock signal having equal periods.

Described is an apparatus comprising: a multi-modulus divider; and a phase provider to receive a multiphase periodic signal and operable to rotate phases of the multiphase periodic signal to generate an output which is received by the multi-modulus divider.

An apparatus includes a digitally controlled oscillator (DCO), which includes an inductor coupled in series with a first capacitor. The DCO further includes a second capacitor coupled in parallel with the series-coupled inductor and first capacitor, a first inverter coupled in parallel with the second capacitor, and a second inverter coupled back-to-back to the first inverter. The DCO further includes a digital-to-analog-converter (DAC) to vary a capacitance of the first capacitor.

An oscillator provides a plurality of clock signals, including a first clock signal having a first frequency and a first period, wherein each clock signal has the first frequency and is phase shifted from the first clock signal by an integer times a predetermined fractional amount of the first period. A multiphase frequency divider receives the plurality of clock signals and provides a divided clock output, and includes an integer frequency divider which provides the divided clock output based on a modified clock input and a clock selector which provides a current clock as the modified clock input during a first portion of the divided clock output and a next clock as the modified clock input during a subsequent portion of the divided clock output. The next clock is selected from the plurality of clock signals based on a selected fractional phase shift amount indicated by a sigma-delta modulator.

A semiconductor device according to the present embodiment includes a plurality of switching elements and a plurality of variable capacitance elements. The switching elements are switching elements connected in series between a first control terminal and a second control terminal and plural types of capacitance control signals can be supplied to the first control terminal and the second control terminal. The variable capacitance elements have capacitance control terminals connected to corresponding one ends of the switching elements, respectively.