Abstract: An oscillator circuit complementarily increases or reduces, in response to a transition of a signal level of a reference clock, a signal level of a first oscillation signal and a signal level of a second oscillation signal. An oscillation control circuit compares the first and second oscillation signals to a comparison voltage, and transitions the signal level of the reference clock in accordance with a result of the comparison. A reference control circuit increases or reduces the comparison voltage so that a difference between a signal level of an intermediate signal which is proportional to respective swings of the first and second oscillation signals and a reference voltage is reduced. A reference voltage control circuit increases or reduces the reference voltage according to a frequency difference between a basis clock and the reference clock.

Abstract: A locked loop circuit includes an oscillator and an extrapolator. The oscillator generates an output signal in response to a control value. The extrapolator determines, based on a first state of the oscillator and a transfer function of the oscillator the control value for the oscillator to transition the oscillator to a second operating state.

Abstract: A clock and data recovery (CDR) architecture which includes a frequency detector, a phase detector, a phase charge pump circuit, a frequency charge pump circuit and a voltage controlled oscillator is provided. The phase detector is configured to only include four AND gates to receive and evaluate the intermediate signals, generated by the frequency detector, and accordingly generate a phase control signal. The voltage controlled oscillator is configured to output a plurality of clock signals with different phases according to the current signals outputted from the phase and frequency charge pump circuits, and select at least one of the plurality of clock signals with different phases for sampling a data signal.

Abstract: Described herein are an apparatus, system and method for timing recovery in processors by means of a simplified receiver architecture that consumes less power consumption, has lower bit error rate (BER), and higher jitter tolerance. The apparatus comprises a phase interpolator to generate a clock signal; a first integrator to integrate a first portion of a data signal over a duration of a phase of the clock signal; a first sampler to sample the first integrated portion by means of the clock signal; a first circuit to store a first edge sample of the data signal; a second sampler to sample the stored first edge sample by means of the clock signal; and a clock data recovery unit to update the phase interpolator based at least on the sampled first integrated portion and sampled stored first edge sample of the data signal.

Abstract: A signal processing module with a timing comparator such as a time to digital converter is provided. The timing comparator comprises an error cancellation stage to remove a predicted effect of the imparted jitter from the timing comparator output signal. A jitter detector is used to detect the jitter from the comparator output signal, preferably residual jitter after the predicted effect of the jitter has been removed. Synchronous detection, such as correlation with the predicted jitter may be used to detect the jitter. The jitter detector adjusts a calibration factor of the timing comparator dependent on the detected jitter.

Abstract: An electronic circuit operating on a first clock signal includes a clock frequency overshoot detection circuit for detecting frequency overshoots in the first clock signal. The clock frequency overshoot detection circuit includes a shift register having an even number plurality of flip-flops. The flip-flops toggle to generate output bit patterns indicative of a frequency overshoot condition. A comparator connected to the shift register generates a comparison signal on detecting the frequency overshoot condition. A latch circuit connected to the comparator generates a frequency overshoot indication signal and the electronic circuit is shifted to a second (or safe) clock signal until the frequency of the first clock signal is rectified.

Abstract: Exemplary embodiments are directed to data and clock recovery in NFC transceivers. A transceiver may include a phase-locked loop configured to recover a clock from a received input signal in a first mode and enable for oversampling of an output signal in a second, different mode.

Abstract: An injection-locked phase-locked loop (ILPLL) with a self-aligned injection window is disclosed. In the ILPLL, a phase detector is provided to detect a phase difference between a pair of differential terminals of an injection-locked voltage-controlled oscillator (ILVCO) of the ILPLL. According to the detection, the phase detector generates a control signal, to align an oscillation output, generated from the pair of differential terminals of the ILVCO, with an injection pulse utilized in the ILVCO.

Abstract: A clock data recovery circuit includes a receiving circuit that takes in input data based on a sampling clock, a demultiplexer that converts serial data output from the receiving circuit into parallel data, a clock/data recovery part that detects phase information from the parallel data output from the demultiplexer and generates the sampling clock by adjusting the phase of a reference clock based on the phase information, a data pattern analyzer that carries out frequency analysis of the parallel data output from the demultiplexer, and an aliasing detector that detects a clock recovery state based on the analysis result of the frequency of the parallel data.

Abstract: A signal generating circuit includes: an operating circuit arranged to generate a first control signal according to a reference clock signal and a feedback oscillating signal; a controllable oscillator arranged to generate an output oscillating signal according to the first control signal and a second control signal; a feedback circuit arranged to generate the feedback oscillating signal according to the output oscillating signal and a third control signal; a control circuit arranged to generate the second control signal and the third control signal according to an input signal; and a calibrating circuit arranged to calibrate the control circuit to adjust the second control signal by detecting a phase difference between the reference clock signal and the feedback oscillating signal.

Abstract: A phase lock loop (PLL) includes a PLL feedback circuit having a feedback divider. The feedback divider has a first dynamic latch, a first logic circuit, and a plurality of serially connected dynamic latches. Each of the serially connected dynamic latches receives and forwards additional data signals to subsequent ones of the serially connected dynamic latches in series. The second-to-last dynamic latch in the series outputs a fourth data signal to a last dynamic latch in the series. The last dynamic latch receives the fourth data signal and outputs a fifth data signal. A first feedback loop receives the fourth data signal from the second-to-last dynamic latch and the fifth data signal from the last dynamic latch. The first feedback loop comprises a NAND circuit that combines the fourth and fifth data signals and the first feedback loop outputs the first feedback signal.

Abstract: A digital control switching power supply unit includes an A/D converter circuit having a delay line circuit that has a delay element array whose delay time is controlled by a bias current, and that converts a current value into a digital signal using a signal transmission delay time, a phase difference detector circuit that detects a phase difference between a switching cycle and an A/D conversion cycle, a charge pump circuit that generates a control voltage in accordance with the phase difference, and a bias current indicator circuit that determines a bias current in accordance with an output voltage of the charge pump circuit and a result of a comparison of a detected value of the output voltage and a reference voltage, wherein the digital control switching power supply unit controls in such a way that the A/D conversion cycle is synchronized with the switching cycle.

Abstract: Methods and apparatus are provided for improving the performance of second order CDR systems. The integral state of the CDR system is initialized to a value that is based on an expected frequency profile that may be known a priori for certain applications. One or more quality of lock (QOL) metrics are also monitored that are derived from the integral register state value. A quality of a locking between a received signal and a local clock generated by a Clock and Data Recovery (CDR) system is evaluated by monitoring a state value of an integral register in a digital loop filter of the CDR system; evaluating one or more predefined criteria based on the integral register state value; and identifying a poor lock condition if the one or more predefined criteria are not satisfied.

Abstract: A phase locked loop includes a phase detector configured to compare a phase of an input clock with a phase of a feedback clock to produce a phase comparison result, an initial frequency value provider configured to detect a frequency of the input clock and provide a frequency detection result, a controller configured to generate a frequency control signal based on the phase comparison result and the frequency detection result, and an oscillator configured to generate an output clock in response to the frequency control signal.

Abstract: One or more PLLs are formed on an integrated circuit. Each PLL includes an interpolative divider configured as a digitally controlled oscillator, which receives a reference clock signal and supplies an output signal divided according to a divide ratio. A feedback divider is coupled to the output signal of the interpolative divider and supplies a divided output signal as a feedback signal. A phase detector receives the feedback signal and a clock signal to which the PLL locks. The phase detector supplies a phase error corresponding to a difference between the clock signal and the feedback signal and the divide ratio is adjusted according to the phase error.

Abstract: In one embodiment, an apparatus includes a jitter generator configured to receive a reference clock; add jitter to the reference clock; and output the reference clock with the included jitter to a phase lock loop (PLL). The PLL is used to generate a local oscillator (LO) signal for a transceiver. A jitter controller outputs a signal to the jitter generator to control a characteristic of the jitter added to the reference clock. The reference clock with the added jitter is used to reduce a fractional spur caused by a radio frequency (RF) attacker coupling into the PLL.

Abstract: The present disclosure discloses a digital phase locking loop and a method. The digital phase locking loop includes a trigger and a delay line. The trigger receives a delayed clock signal output by the delay line, and receives a signal of a selection end of a first delay element in the delay line; the selection end is in a gating state before triggering of the trigger. The trigger samples the signal of the selection end of the first delay element, and outputs the sampled signal to a selection end of a second delay element in the delay line; the selection end of the second delay element is in the gating state after triggering of the trigger. The signal of the selection end of the first delay element is sampled by the trigger, and the sampled result is used as the signal of the selection end of the second delay element, thus reducing glitches caused by transition.

Abstract: Phase error of a time-to-digital converter (TDC) within an all-digital phase-locked loop (ADPLL) is compensated by predicting possible phase error, which are predicted according to an estimated quantization error, a period of a digital-controlled oscillator (DCO), a gain of the TDC or a combination thereof. By appropriate inductions, the possible phase error may be further indicated by the quantization error, a code variance corresponding to a half of a reference period received by a TDC module having the TDC, a dividing ratio of a frequency divider of the ADPLL, a fractional number related to the quantization error or a combination thereof. A digital phase error cancellation module is also used for generating the possible phase error for compensating the phase error of the TDC.

Abstract: A clock generator circuit for producing a clock output having a controlled duty cycle is disclosed. A bi-stable circuit provides the clock output which is switchable to a first state in response to an edge of the input clock signal and to a second state in response to a feedback signal. A duty cycle detection circuit is configured to source a current to a node and to sink a current from the node depending upon the output clock state. A capacitor is connected to receive a duty cycle current relating to the current at the node, with a comparator circuit being configured to sense a voltage on the capacitor and to produce the feedback signal when the voltage is at a selected level.

Abstract: A digital phase-locked loop apparatus using FSK includes a PFD detecting phase differences between a reference clock and a frequency-divided signal, and a first adder for generating first digital control codes by adding first digital codes, second digital codes, and channel frequency codes including channel information to each other, the first digital codes being converted from time differences between first and second pulses. The apparatus further includes a digital filter correcting errors of the first digital control codes to generate second digital control codes, a DCO for varying an oscillating frequency in accordance with a digital tuning word based on the second digital control codes, and a dual modulus division unit dividing the oscillating frequency into a frequency-divided signal.

Abstract: A signal generator provides a plurality of oscillating signals, whereby each oscillating signal has a different peak voltage and has a predictable and consistent phase relationship with the other oscillating signals. The signal generator includes a plurality of stacked oscillators arranged between two reference voltages, such that each oscillator in the stack generates an oscillating signal having a different peak voltage. Each oscillator stage in a designated oscillator includes a transistor that is connected to a transistor of a corresponding stage in another oscillator. This arrangement of the oscillators provides for charge transfer between the corresponding stages to provide for similar voltage swings in each oscillating signal, as well as to provide for predictable phase relationship between the oscillating signals.

Abstract: Control circuitry and method of controlling for a sampling phase lock loop (PLL). By controlling the duty cycle of a sampling control signal, in accordance with the PLL reference and output signals, spurious output signals from the sampling PLL being controlled can be reduced.

Abstract: A dual loop PLL for generating an oscillator signal initially operates in a digital loop to achieve a frequency lock between an input reference signal and a feedback signal and then the PLL operates in an analog loop to achieve a phase lock. After attaining the phase lock, the analog loop is used to maintain the phase lock across frequency and phase variation due to changes in temperature and supply.

Abstract: A method and apparatus for generating a clock that can be switched in phase within a reduced interval of dead time are disclosed.

Abstract: The present invention relates to a PLL circuit and an associated method that allows the PLL circuit to operate at a higher operating frequency with a wider bandwidth and a better out-band noise suppression. The PLL circuit comprises a delay locked loop (DLL), a phase-frequency detector (PFD), a loop filter, a voltage controlled oscillator (VCO) and a frequency divider.

Abstract: Provided is a PLL circuit including automatic frequency control circuit and an operating method thereof. The voltage controlled oscillator is primarily controlled by an automatic frequency control circuit, and is secondarily controlled by a loop filter. The voltage controlled oscillator outputs a coarsely-tuned oscillation signal when primarily controlled, and outputs a finely-tuned oscillation signal when secondarily controlled. The PLL circuit can have a quick frequency fixing time, and output the oscillation signal having a broad and stable frequency. Moreover, the noise characteristic of the PLL circuit is enhanced.

Abstract: A clock generator having a delay locked loop and a delay control circuit. The delay locked loop receives an input clock signal and adjusts an adjustable delay circuit to generate an output clock signal that is synchronized with received input clock signal. The delay control circuit coupled to the delay locked loop generates a control signal to initialize the delay measure operation to adjust the adjustable delay circuit, after comparing the phase difference of the input clock signal and the output clock signal. The delay control circuit further generates a start measure control signal to start measuring a delay applied to the measurement signal propagating through the adjustable delay circuit, and generates a stop measure control signal to stop the delay measurement of the measurement signal. The delay adjustment of the delay locked loop is then adjusted to apply the delay measurement when synchronizing the input and output clock signals.

Abstract: Frequency synthesizer with immunity from oscillator pulling. The frequency synthesizer for generating an output frequency includes an oscillator that is capable of generating a first frequency. The frequency synthesizer also includes an output divider coupled to the oscillator. The output divider is configurable to allow the oscillator to generate a second frequency to prevent degradation in phase noise due to an interference to the first frequency of the oscillator, and to generate the output frequency from the second frequency.

Abstract: An all digital phase-locked loop (ADPLL) includes: a phase counter accumulating a frequency setting word value and the phase of a digitally controlled oscillator (DCO) clock and detecting a fine phase difference between a reference clock and a retimed clock; a phase detector detecting a digital phase error value compensating for a phase difference between the frequency setting word value and the DCO clock according to the fine phase difference to detect a digital phase error value; a digital loop filter filtering the digital phase error value and controlling PLL operational characteristics; a lock detector generating a lock indication signal according an output of the digital loop filter; a digitally controlled oscillator varying the frequency of the DCO clock according to the output from the digital loop filter; and a retimed clock generator generating the retimed clock by retiming the DCO clock at a low frequency.

Abstract: A PLL circuit is provided capable of reducing phase noise and facilitating design. In the PLL circuit, a PLL receives a reference frequency and an output from a VC-TCXO, performs a lock operation. In a lock state, a selector selects an output of a first divider that divides the reference frequency. When PLL detects input of reference frequency being lost or an unlock state, the PLL outputs an alarm signal to the selector. When receiving the alarm signal from the PLL, the selector switches from the output of the first divider to an output of a second divider that frequency-divides an output of the VC-TCXO, and outputs the same. Then, a PLL receives an output of the selector and an output of a VCXO and performs a lock operation.

Abstract: A delay locked loop (DLL) of a semiconductor integrated circuit includes a first delay line configured to variably delay a source clock signal and output a locked clock signal, a phase comparator configured to compare the phase of the source clock signal with the phase of a feedback clock signal, a second delay line configured to variably delay the locked clock signal, a first delay controller configured to control the first delay time of the first delay line, a second delay controller configured to control the minimum delay time of the second delay line, and an operation mode controller configured to control the first and second delay controllers in response to an output signal of the phase comparator, and switch operation modes of the first and second delay controllers depending on locking state of the delay lines.

Abstract: A reference quantity generator for generating a reference quantity includes a reference source configured to provide a reference source signal, a digitally controlled signal source and a digital controller. The digitally controlled signal source is configured to provide a digitally controlled quantity. The reference quantity is determined based on the digitally controlled quantity. The digital controller is configured to provide a digital control signal to control the digitally controlled signal source to adapt the digitally controlled quantity based on the reference source signal using a feedback.

Abstract: A phase locked loop (PLL) device is configurable in an analog phase locked loop and a hybrid analog-digital phase locked loop. In an analog mode, at least a phase detector, an analog loop filter, and a voltage controlled oscillator (VCO), are connected to form an analog loop. In a digital mode, at least the phase detector, the voltage controlled oscillator (VCO), a time to digital converter (TDC), a digital loop filter and a digital to analog converter (DAC) are connected to form the hybrid digital-analog loop.

Abstract: An improved approach is described for implementing a clock management system. A multi-part phase locked loop circuit is provided to handle the different clock needs of the circuit, where each of the phase locked loops within the multi-part phase locked loop circuit may feed a clock output to one or more divider circuits. The divider circuits may be dedicated to specific components. For example, a SoC PLL may generate a clock output to a SoC divider that is dedicated to providing a clock to content address memory (CAM) components. This approach allows the clock management system to efficiently generate clock signals with variable levels of frequencies, even for complicated circuits having many different functional portions and components.

Abstract: A phase locked loop control system includes a digital controlled oscillator (DCO) that is controlled by logic cells in response to comparison of the oscillator output with a reference clock related signal. Delay cell number adjustment, delay cell load adjustment and cycle control are operative to digitally control the DCO frequency to obtain wide frequency range and limited jitter.

Abstract: A charge pump includes an UP current mirror and a DN current mirror. The UP current mirror is controlled by an input UP signal and supplies charge onto an output node. The DN current mirror is controlled by an input DN signal and draws charge from the output node. The input UP and DN signals may be received from a phase detector in a Phase-Locked Loop (PLL). To prevent disturbances on bias nodes of the UP and DN current mirrors that otherwise might occur, replica circuits of portions of the UP and DN current mirrors are provided. Each replica circuit is coupled to a bias node of a corresponding current mirror, but is controlled by an input signal of opposite polarity to the input signal that controls the current mirror so that the replica circuit creates disturbances that tend to counteract disturbances created by switching of the current mirror.

Abstract: A programmable memory interface circuit includes a programmable DLL delay chain, a phase offset control circuit and a programmable DQS delay chain. The DLL delay chain uses a set of serially connected delay cells, a programmable switch, a phase detector and a digital counter to generate a coarse phase shift control setting. The coarse phase shift control setting is then used to pre-compute a static residual phase shift control setting or generate a dynamic residual phase shift control setting, one of which is chosen by the phase offset control circuit to be added to or subtracted from the coarse phase shift control setting to generate a fine phase shift control setting. The coarse and fine phase shift control settings work in concert to generate a phase-delayed DQS signal that is center-aligned to its associated DQ signals.

Abstract: The present invention provides ABS precision improving means under ADPLL environment or environment close to the ADPLL environment and realizes shortening of process time of the ABS. In a digital frequency comparator in an ABS circuit, a DFF for storing an initial phase difference in a DPE signal output from a DPFD is prepared. Immediately after start of ABS operation, a DPE signal output from the DPFD is recorded as a signal expressing an initial phase difference in an internal circuit of the DPFD into the DFF. After that, the digital frequency comparator performs ABS by using a signal obtained by subtracting the initial phase error recorded in the DFF from an input DPE signal, thereby realizing high-speed and stabilized ABS operation.

Abstract: Controlling a PLL includes providing a voltage controlled oscillator (VCO) and coupling an output of the VCO to a shifter circuit. The shifter circuit has a shifter circuit output, the shifter circuit also including an activation input for receiving an activation signal, the shifter circuit causing at least one pulse of the output signal to be suppressed at the shifter output upon receipt of the activation signal. Controlling also includes coupling the shifter circuit output to a first frequency divider.

Abstract: Embodiments include implementing a phase detector for a delay-locked loop (DLL) circuit that is operable to detect substantially 270 degree and substantially 540 degree phase differences between two clock signals.

Abstract: Digitally controllable delay lines including fine grain and coarse grain delay elements, and methods and system to calibrate the delay lines in fine grain increments. Calibration may include calibrating a number of fine grain elements for which a combined delay is substantially equal to a delay of a coarse grain element, and calibrating numbers of fine grain and coarse grain elements which a combined delay corresponds to a period of a reference clock. A digitally controlled delay line may be implemented as part of a digital delay locked loop (DLL), and calibration parameters may be provided to a slave DLL having a similarly implemented delay line. A digitally controllable DLL may provide relatively low-power, high-resolution over a spectrum of process, voltage, and temperature variations, and may be implemented in relatively high-speed applications previously reserved for analog DLLs.

Abstract: An apparatus for clock/voltage scaling includes a device power manager arranged to supply a scalable frequency clock to an interface; a delay-locked loop, supplied by a constant fixed frequency clock and a constant voltage, arranged to generate a unique code depending on process, voltage, and/or temperature; and controlled delay line elements coupled to the delay-locked loop, arranged to generate an appropriate delayed data strobe based on the unique code. A method for a digital phase lock loop high speed bypass mode includes providing a first digital phase lock loop in a first high speed clock domain; providing a second digital phase lock loop in a second clock domain; controlling an output of a first glitchless multiplexer according to preselected settings using a device power manager synchronized locally; and controlling an output of a second glitchless multiplexer using a control logic element of the second digital phase lock loop.

Abstract: A digital PLL circuit includes: a digital phase comparator to detect a phase difference between a master clock and a slave clock and output a phase difference detection value; a correction circuit to correct the phase difference detection value to a phase value in accordance with a comparison result between the phase difference detection value and a threshold; and a slave clock generation circuit to generate the slave clock in accordance with the phase value.

Abstract: A locked loop may have an adjustable hysteresis and/or a tracking speed that can be programmed by a user of an electronic device containing the locked loop or controlled by an integrated circuit device containing the locked loop during operation of the device. The looked loop may include a phase detector having a variable hysteresis, which may be coupled to receive a reference clock signal and an output clock signal from a phase adjustment circuit through respective frequency dividers that can vary the rate at which the phase detector compares the phase of the output clock signal to the phase of the reference clock signal, thus varying the tracking speed of the loop. The hysteresis and tracking speed of the locked loop may be programmed using a variety of means, such as by a temperature sensor for the electronic device, a mode register, a memory device command decoder, etc.

Abstract: An onion waveform generator and a spread spectrum clock generator (SSCG) using the same are provided. The onion waveform generator includes a value generation unit and an accumulating unit. The value generation unit outputs a counting value. The accumulating unit accumulates the counting value to output a waveform value. The accumulating unit switches from an increasing mode to a decreasing mode if the waveform value is a third boundary value, and the accumulating unit switches from the decreasing mode to the increasing mode if the waveform value is a fourth boundary value.

Abstract: The invention relates to the conversion into digital information of the time difference between a first signal and a second signal. In particular, in order to determine a fractional part of the number of periods of a first signal for a period of a second signal, the following are alternately performed: /1/ delaying the second signal relative to the first signal and determining a first digital information item, a function of the fractional part, /2/ delaying the first signal relative to the second signal and determining a second digital information item, a function of the fractional part. Then the fractional part is calculated as a function of the previously obtained first and second digital information items.

Abstract: A PLL circuit includes a polyphase reference clock output circuit that outputs reference clocks, a polyphase frequency divider circuit that outputs divided clocks, which is obtained by dividing frequencies of the reference clocks, a selection switch circuit that selects one of the reference clocks or one of the divided clocks, and outputs the selected clock as a selected clock, a digital VCO that uses the selected clock as an operating clock, and outputs delay amount data indicating a phase difference between an output clock and an ideal phase, where the output clock has a frequency that fluctuates according to a value of frequency control input data, and the ideal phase is calculated according to the output clock and the value of the frequency control input data, and a selection circuit that selects and outputs the output clock synchronized with the divided clocks according to the delay amount data.

Abstract: A clock generator is disclosed that includes a lock detector. The lock detector is configured to generate a lock signal based on control signals of a phase lock loop circuit that generates an output clock of a desired frequency that is phase locked to a reference clock. The lock detector generates a mismatch signal based on a comparison between the phases of the reference clock and the output clock to generate a compare result. The lock detector delays the compare result by a time period Td and AND the delayed compare result with the compare result to generate the mismatch signal. The lock detector includes a lock-counter that counts a number of reference clock cycles when the mismatch signal remains at 0. The lock signal indicates that a lock-state is achieved when the number of counted reference clock cycles equals a set-value.

Abstract: A spread spectrum clock generator includes a voltage-controlled oscillator generating an operation clock, a feedback control unit, a modulated pulse generation unit generating a pulse signal obtained by performing a delta-sigma modulation on a component fluctuating a frequency of the operation clock, a level set unit setting an amplitude of the pulse signal, an adder adding a voltage generated by the feedback control unit and the pulse signal whose amplitude is set by the level set unit, and a low pass filter filtering a signal outputted from the adder and generating a control voltage applied to the voltage-controlled oscillator. The feedback control unit compares a phase of the operation clock with a phase of a reference clock, and based on results of the comparison, generates a voltage used as a reference to oscillate the voltage-controlled oscillator.

Abstract: A delay locked loop includes initialization circuitry that ensures that a DLL is initialized to an operating point that is not to close to either end of a delay vs. control voltage characteristic. The initialization circuitry forces the DLL to initially search for a lock point starting from an initial delay, the delay is varied in one direction, forcing the DLL to skip the first lock point. The initialization circuitry only allows the DLL to vary the delay of the voltage controlled delay loop in the one direction from the initial delay until the operating point is reached.