A duty adjustment circuit, and a delay locked loop circuit and a semiconductor memory device including the same are provided. The duty adjustment circuit includes a pulse generator configured to generate a pulse signal at a constant pulse width regardless of a frequency of a reference clock signal, based on frequency information, a code generator configured to generate a first predetermined number of delayed pulse signals by delaying the pulse signal, as a first code in response to the pulse signal, and a duty adjuster configured to receive a delay clock signal, and generate a duty correction clock signal by adjusting a slope of rising transition and a slope of falling transition of the delay clock signal in response to the first code and a second code.

In a method and device to align phases of a first clock signal and a second clock signal, include a phase detector, a delay generator, and a controller. The phase detector is configured to generate a preceding signal and a succeeding signal with respect to the first clock signal to detect a relationship between phases of the first clock signal and the second clock signal. The delay generator is configured to delay the first clock signal when the second clock signal falls behind the succeeding signal with respect to the first clock signal. The controller is configured to determine whether the phases of the first clock signal and the second clock signal are aligned with each other according to the relationship detected by the phase detector.

A synchronization circuit may include: a delay line configured to delay a reference clock signal; a division circuit configured to generate a divided feedback clock signal by dividing a feedback clock signal at a division ratio which is set according to a division ratio control signal; a phase detection circuit configured to generate a phase detection signal by detecting the phase of the divided feedback clock signal based on the reference clock signal; and a delay line control circuit configured to control a delay time of the delay line according to the phase detection signal and the divided feedback clock signal.

A system for generating an RFPWM signal comprises a delta sigma modulator having a plurality of outputs, a phase-locked loop comprising a plurality of phase quantization outputs, at least one multiplexer having a plurality of signal inputs, a plurality of selector inputs, and at least one output, the signal inputs communicatively connected to the phase quantization outputs of the phase-locked loop and the selector inputs electrically connected to the outputs of the delta sigma modulator, and a driver having an input communicatively connected to the output of the multiplexer and an output generating an RFPWM signal. A method of generating an RFPWM signal is also described.

An example method for clock and data recovery (CDR) includes generating, in a set of slicers of a receiver, in addition to a data signal and a first error signal, at least one additional error signal. The method further includes receiving, at a frequency detector (FD) of a CDR unit of the receiver, the data signal, the first error signal, and the at least one additional error signal, and processing them to generate a FD output. The method still further includes multiplying the FD output by a user-defined FD gain, and adding the FD output, as multiplied by the FD gain, in a frequency path of the CDR unit.

A phase-locked loop according to the present disclosure includes a reference-phase generation circuit that sequentially generates a reference phase value, and an oscillating circuit that generates a first clock on a basis of a difference between the reference phase value and a feedback phase value. The phase-locked loop further includes a signal generation circuit that generates, on a basis of the first clock, a plurality of second clocks varying in phase, and generates a third clock by switching the plurality of second clocks a plurality of times in each of cycle periods each corresponding to one cycle of the reference clock. The phase-locked loop further includes a phase detection circuit that determines a phase value of the third clock and outputs the determined phase value as the feedback phase value.

A delay-locked loop includes a voltage control delay line and a phase detector. The phase detector includes: a sampler unit generating multiple samples obtained by sampling a data signal in a time interval corresponding to a half of a unit interval based on a clock; a mode selection unit selecting a series of samples among the multiple samples in such a way that the mode selection unit selects the series of samples starting from an odd-numbered sample, or selects the series of samples starting from an even-numbered sample, according to a mode selection signal; and an XOR unit performing an XOR operation on the samples that are adjacent to each other and outputting an operation result, the output operation result is used for controlling the voltage-controlled delay line. The delay-locked loop can greatly reduce power consumption and an area of the voltage control delay line.

An example method for clock and data recovery (CDR) includes generating, in a set of slicers of a receiver, in addition to a data signal and a first error signal, at least one additional error signal. The method further includes receiving, at a frequency detector (FD) of a CDR unit of the receiver, the data signal, the first error signal, and the at least one additional error signal, and processing them to generate a FD output. The method still further includes multiplying the FD output by a user-defined FD gain, and adding the FD output, as multiplied by the FD gain, in a frequency path of the CDR unit.

A clockless delay adaptation loop configured to adapt to random data includes a first and a second delay line, an autocorrelator, and a controller. The autocorrelator receives an input signal for the delay adaptation loop and the output from the first delay line, and includes a first logic circuit configured to output a first autocorrelation and a second logic circuit configured to output a second autocorrelation. The controller is configured generate a control signal for one of the first and second delay lines based on the first and second autocorrelations. In some examples, the first logic circuit is an XNOR gate, and the second logic circuit is an OR gate. In some examples, the OR gate can have a gain that is two times a gain of the XNOR gate. In some examples, an amplifier having two times the gain of the XNOR gate is coupled to the OR gate.

A method of calibrating a clock phase and a voltage offset includes receiving an input data signal that is periodically toggled. A clock phase calibration operation is performed based on an up signal and a down signal, such that phases of a plurality of clock signals are adjusted. The up signal and the down signal are generated based on the input data signal, a reference voltage and the plurality of clock signals. A voltage offset calibration operation is performed based on the up signal, the down signal and a first sample data signal, such that a voltage level of the reference voltage is adjusted. The first sample data signal is generated by sampling the input data signal based on one of the plurality of clock signals. The clock phase calibration operation and the voltage offset calibration operation are performed independently of each other and not to overlap with each other.