A clock data recovery circuit includes a bang bang phase detector receiving data and a clock signal and determining whether a phase of the clock signal leads or lags a phase of the data, a digital loop filter receiving an output of the bang bang phase detector and filtering input jitter, an accumulator accumulating an output from the digital loop filter, an encoder encoding an output of the accumulator to generate a phase interpolation code, and a phase interpolator configured to generate the clock signal with an output phase in accordance with the phase interpolation code. The digital loop filter comprises a first sigma delta modulation (SDM) arithmetic block circuit connected to the bang bang phase detector.

A memory controller may include: a request checker identifying memory devices corresponding to requests received from a host among the plurality of memory devices and generating device information on the identified memory devices to perform operations corresponding to the requests; a dummy manager outputting a request for controlling a dummy pulse to be applied to channels of selected memory devices according to the device information among the plurality of channels; and a dummy pulse generator sequentially applying the dummy pulse to the channels coupled to the selected memory devices, based on the request for controlling the dummy pulse. A memory controller may include an idle time monitor outputting an idle time interval of the memory device and a clock signal generator generating a clock signal based on the idle time interval and outputting the clock signal to the memory device through the channel to perform a current operation.

A memory controller may include: a request checker identifying memory devices corresponding to requests received from a host among the plurality of memory devices and generating device information on the identified memory devices to perform operations corresponding to the requests; a dummy manager outputting a request for controlling a dummy pulse to be applied to channels of selected memory devices according to the device information among the plurality of channels; and a dummy pulse generator sequentially applying the dummy pulse to the channels coupled to the selected memory devices, based on the request for controlling the dummy pulse. A memory controller may include an idle time monitor outputting an idle time interval of the memory device and a clock signal generator generating a clock signal based on the idle time interval and outputting the clock signal to the memory device through the channel to perform a current operation.

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 novel phase locked loop design utilizing novel phase-frequency detector, charge pump, loop filter and voltage controlled oscillator is disclosed. The phase-frequency detector includes a dual reset D-flip flop for use in multi-GHz phase locked loops. Traditional dead zone issues associated with phase frequency detector are improved/addressed by use with a charge transfer-based PLL charge pump.

A time to digital converter has a counter, a first phase difference detector, a first capacitor, a second capacitor having capacitance N times a capacitance of the first capacitor, a comparator to compare a charge voltage of the first capacitor with a charge voltage of the second capacitor, a first charge controller, a first phase difference arithmetic unit, a second phase difference detector, a second charge controller, a second phase difference arithmetic unit to operate the phase difference between the first signal and the second signal, and a third phase difference arithmetic unit to detect a fractional phase difference between the first signal and the second signal. The first phase difference arithmetic unit operates the phase difference between the first signal and the second signal, based on a reference phase, when the counter suspends a measurement operation.

A master-slave delay locked loop system comprises a master delay locked loop (“MDLL”) and at least one slave delay locked loop (“SDLL”). The MDLL generates one or more biases. Each of the at least one SDLL has a slave calibration unit and slave delay elements. The slave calibration unit calibrates the slave delay elements using a slave calibration loop and the generated one or more bias. Thus, each of the SDLL is calibrated to account for any electrical noise, pressure, voltage, and temperature variations that the respective SDLL experiences.

An integrated circuit with a phase-locked loop (PLL) is provided. The PLL may include a phase frequency detector, a charge pump, a source follower circuit, a variable oscillator, a frequency divider, and a control block. The phase frequency detector may be configured to align or lock a feedback clock signal to a reference clock signal. The control block includes clock loss detection circuits that are used to determine whether the reference clock signal or the feedback clock signal has stopped toggling. In response to detecting a clock loss event for either the reference or the feedback clock signal, the control block may disable the phase frequency detector to place the charge pump in a tristate mode and may apply a predetermined bias voltage to the source follower circuit to help minimize electrical overstress.

In a PLL circuit, first an ILFD is connected to an output voltage Vtune from an LPF, thereby causing the ILFD to operate as an oscillator. The ILFD, a DIV, PFD, CP, and LPF form a PLL and thereby locking operations are initiated. When a predetermined time elapses, an output frequency from the ILFD converges into a certain value and the PLL is subjected to a locked state. After the locked state is reached, a sample hold circuit SH holds the output voltage Vtune from the loop filter as of that time and frequency adjustment of the ILFD is completed. Similar frequency adjustment is sequentially performed on other ILFDs.

An apparatus includes a signal generator. The signal generator includes a voltage controlled oscillator (VCO) coupled to provide an output signal having a frequency. The signal generator further includes an asymmetric divider coupled to receive the output signal of the VCO and to provide an output signal. The output signal of the asymmetric divider has a frequency that is half the frequency of the output signal of the VCO. The asymmetric divider presents a balanced load to the VCO.