Described is a low power and low jitter phase locked loop (PLL) or delay locked loop (DLL) with digital leakage compensation. The compensation is provided by an apparatus which comprises: a circuitry to generate a pulse with a digitally controlled pulse width, wherein the pulse width is proportional to a static phase error of a PLL or a DLL; and a charge pump coupled to the circuitry, wherein the charge pump is to receive the pulse and to source or sink current to or from a node according to the pulse width.

Described is a low power and low jitter phase locked loop (PLL) or delay locked loop (DLL) with digital leakage compensation. The compensation is provided by an apparatus which comprises: a circuitry to generate a pulse with a digitally controlled pulse width, wherein the pulse width is proportional to a static phase error of a PLL or a DLL; and a charge pump coupled to the circuitry, wherein the charge pump is to receive the pulse and to source or sink current to or from a node according to the pulse width.

Provided is a circuit device including: 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 of the waveform signal 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 clock generator circuit includes a charge pump unit, a low-pass filter unit, a current-controlled clock generator and a voltage-to-current converter unit. The charge pump unit provides a pump current at an output terminal thereof. The low-pass filter unit is coupled to the output terminal of the charge pump unit, and develops a control voltage at an output terminal thereof based on the pump current. The voltage-to-current converter unit is coupled to the output terminal of the low-pass filter unit, the current-controlled clock generator and the charge pump unit, and provides a control current to the current-controlled clock generator. Each of the low-pass filter unit and the voltage-to-current converter unit includes a resistive element.

Provided is clock signal generator configured to generate a target output clock signal based on a reference clock signal, the clock signal generator includes a digital-to-time converter (DTC) configured to delay a reference clock signal based on an input code to generate a delay clock signal, and output the delay clock signal, a DTC controller configured to determine an initial gain value of the DTC based on a result of comparing at least one delay amount of the DTC with a period of a previously generated output clock signal, and generate the input code based on the initial gain value, and a phase locked loop configured to generate the target output clock signal based on the delay clock signal and a division clock signal of the previously generated output clock signal, the target output clock signal being locked to the delay clock signal.

A PLL frequency synthesizer includes a voltage controlled oscillator that outputs an oscillation signal having a frequency corresponding to a control voltage value, a phase comparison unit that outputs a phase difference signal representing a phase difference between a feedback oscillation signal and a reference oscillation signal, a charge pump that outputs a charge and discharge current according to the phase difference, a loop filter that outputs the control voltage value, which is increased or decreased according to a charge and discharge amount of a capacitive element, to the voltage controlled oscillator, a detection unit that detects a change rate of the control voltage value, and a control unit that adjusts the charge and discharge current, a characteristic of the loop filter, or a characteristic of the voltage controlled oscillator based on a detection result of the detection unit.

A clock and data recovery circuit includes a sampling circuit, a phase detector, a first processing circuit, a second processing circuit and an oscillator circuit. The sampling circuit is configured to sample input data according to an output clock, and generate a sampling result. The phase detector is configured to generate a detection result according to the sampling result. The first processing circuit is configured to process the sampling result to generate a first digital code. The second processing circuit is configured to accumulate a portion of the first digital code to generate a second digital code. A rate of change of a code value of the second digital code is slower than a rate of change of a code value of the first digital code. The oscillator circuit is configured to generate the output clock according to the detection result, the first digital code and the second digital code.

A clock generator circuit includes a charge pump unit, a low-pass filter unit, a current-controlled clock generator and a voltage-to-current converter unit. The charge pump unit provides a pump current at an output terminal thereof. The low-pass filter unit is coupled to the output terminal of the charge pump unit, and develops a control voltage at an output terminal thereof based on the pump current. The voltage-to-current converter unit is coupled to the output terminal of the low-pass filter unit, the current-controlled clock generator and the charge pump unit, and provides a control current to the current-controlled clock generator. Each of the low-pass filter unit and the voltage-to-current converter unit includes a resistive element.

A PLL circuit of one embodiment has a structure for preferably setting the FV characteristic of an LC-VCO. The PLL circuit includes a voltage controlled oscillator, a phase comparator, a charge pump, a loop filter, and an FV characteristic adjustment unit setting the FV characteristic. The voltage controlled oscillator has an FV characteristic indicating the relationship between a control signal and a frequency and outputs an oscillation signal having a frequency corresponding to the control signal based on the FV characteristic. The phase comparator detects a phase difference between an input signal and the control signal. The charge pump outputs a corrected voltage value changed according to the phase difference. The loop filter outputs a control voltage value changed in response to corrected voltage value variations. The FV characteristic adjustment unit generates an FV characteristic control signal by a mean corrected voltage value.

Apparatus and methods for timing offset compensation of frequency synthesizers are provided herein. In certain embodiments, an electronic system includes a frequency synthesizer, such as a fractional-N phase-locked loop (PLL), which generates an output clock signal based on timing of a reference clock signal. Additionally, the electronic system includes an integer PLL configured to compensate for a timing offset, such as a phase offset and/or frequency offset, of the frequency synthesizer based on timing of the output clock signal.