Abstract: A semiconductor integrated circuit includes a delay locked loop (DLL) control block configured to generate a buffer enable signal, the buffer enable signal being a pulse signal that is periodically enabled when a smart power down signal is enabled, and a DLL circuit configured to control a phase of an external clock signal in response to the buffer enable signal to generate an output clock signal.

Abstract: Methods and apparatus are provided for improved startup of a voltage controlled delay loop that has an injection clock and a return clock. A control signal is determined for a plurality of delay elements in a voltage controlled delay loop by obtaining a histogram count of a number of occurrences of at least one predefined logic value for a plurality of delay settings of the voltage controlled delay loop; determining a histogram count that approximately corresponds to an alignment of at least one edge in the injection and return clocks; and determining the control signal based on the determined histogram count that approximately corresponds to the alignment. The voltage controlled delay loop can be started using the deter wined control signal. The histogram count can be obtained for a plurality of PVT combinations and the control signal can then be determined for each PVT combination.

Abstract: Some embodiments include a delay line configured to apply a delay to an input signal to provide an output signal; an input circuit configured to provide the input signal based on a first signal, such that the cycle time of the input signal is different from a cycle time of the first signal; an output circuit configured to provide a second signal based on the output signal, the second signal having a cycle time different from a cycle time of the output signal; and a controller configured to adjust the delay to control a timing relationship between the first signal and the second signal. Other embodiments are described and claimed.

Abstract: A clock distribution device to an exemplary aspect of the invention includes: a first clock output unit outputting a first clock synchronized to a reference clock; a second clock output unit outputting a second clock synchronized to the reference clock; a first clock distribution unit including a first branch point, branching the first clock at the first branch point and outputting a third clock; a second clock distribution unit including a second branch point, branching the second clock at the second branch point and outputting a fourth clock; and a phase difference detecting unit detecting a first phase difference between a phase of the third clock and a phase of the fourth clock, and the second clock output unit controls a second phase difference between a phase of the first clock and a phase of the second clock so that the first phase difference is reduced.

Abstract: A semiconductor memory apparatus having a clock signal generation circuit and a data output circuit is presented. The apparatus includes a delay locked loop (DLL), a phase locked loop (PLL), a frequency discrimination unit, and a data output buffer. The DLL circuit is configured to negatively delay a clock signal to generate a DLL clock signal. The PLL circuit is configured to receive the DLL clock signal to generate a control voltage in response to a frequency of the DLL clock signal and to generate a PLL clock signal of a frequency corresponding to a level of the control voltage. The frequency discrimination unit is configured to discriminate a frequency of the DLL clock signal in accordance with the level of the control voltage to generate a frequency discrimination signal. The data output buffer is configured to receive the DLL clock signal or the PLL clock signal to buffer output data signals.

Abstract: A scalable DLL (delay locked loop) circuit that has a calibration mechanism to auto tune locking precision. The delay locked loop circuit includes a multi-phase phase locked loop circuit for generating a plurality of phase signals according to a system clock, wherein one of the phase signals is a pixel clock; a phase detector for detecting an integral phase error and a fractional phase error between a reference signal and a feedback signal according to the pixel clock; a phase selector for selecting one of the phase signals according to the fractional phase error; and a delay circuit for shifting the phase of the reference signal according to the integral phase error and the selected phase signal to generate an output signal.

Abstract: A data center tracking circuit includes a clock tree, a sensing block, and a delay compensation block. The clock tree includes a plurality of clock buffers connected in series, buffers a clock, and outputs an output signal. The sensing block senses the phase change of the output signal on the basis of the clock, and outputs a sensing signal. The delay compensation block adjusts current to be supplied to the clock tree in response to the sensing signal, and adjusts the phase of the output signal.

Abstract: Provided herein are approaches for controlling remote slave DLL circuits with a master DLL circuit by conveying a relevant bias signal as a current signal instead of as a voltage signal.

Abstract: A method and apparatus is provided for providing a fine delay by switching on a capacitor delay. A coarse delay and/or a fine delay are implemented upon a reference signal based upon a phase shift between the reference signal and a feedback signal. A fine delay is implemented upon the reference signal based upon a phase shift between the reference signal and a feedback signal. Providing the fine delay includes switching on a capacitive delay. A synchronized output signal is generated based upon the fine delay.

Abstract: A phase synchronization apparatus includes a bias control unit configured to sequentially delay an input clock signal to generate bias control signals having multiple bits, a bias generation unit configured to generate a pull-up bias voltage having a level that corresponds to logical values of the bias control signals, and to generate a pull-down bias voltage in response to a control signal; and a voltage controlled oscillator configured to include a plurality of delay cells respectively having a pull-up terminal and a pull-down terminal to generate an output clock signal in response to the control voltage, wherein the pull-up bias voltage is supplied to the pull-up terminals of the respective delay cells and the pull-down bias voltage is supplied to the pull-down terminals of the respective delay cells.

Abstract: The semiconductor integrated circuit includes a clock generating section having a digital control signal generating part operable to generate a clock signal and a digital control part. The clock generating section further includes a phase-frequency comparator and a control register. The comparator is supplied with a reference signal CLKin and a feedback signal. The control register is supplied with an output signal of the comparator, and stores two or larger bits of digital control information. The clock generating section further includes a control data storing circuit for previously storing sets of initial set data for lock operations. In response to operation select information, initial set data are stored at upper bit of the control register from the control data storing circuit. Thus, it becomes possible to reduce the number of steps to store control information in a register for digitally controlling the clock signal generating part.

Abstract: A Phase Lock Loop (PLL) with gain control is provided. The PLL has a dual-path configuration, where a first and a second VCO control voltage are generated in response to a phase or frequency difference between a PLL input signal and an output signal. The PLL comprises a dynamic voltage gain control (DVGC) unit and a voltage-to-current (V2I) unit, where the DVGC creates a baseline reference current in response to the first VCO control voltage and the V2I provides a substantially linear current in response to the second VCO control voltage. The currents from the DVGC and V2I are combined and fed into a current-controlled oscillator, which generates a PLL output frequency signal. Frequency gain of the VCO is substantially reduced, thus providing a PLL with improved tuning precision.

Abstract: The object is to provide a delay circuit capable of improving the accuracy of delay time with a simple circuit configuration. A delay circuit includes a first delay unit including a plurality of delay elements connected in series for detecting delay time characteristics of the first delay unit, a detection unit detects the number of delay elements used in the first delay unit to delay an input signal by a reference time, a second delay unit including a plurality of delay elements connected in series so as to output a signal delayed in accordance with the delay time characteristics of the first delay unit, and a selection unit selects the number of delay elements in the second delay unit to delay the input signal in accordance with the number of delay elements detected by the detection unit.

Abstract: Embodiments of the present disclosure provide methods, systems, and apparatuses related to a delay element array for time-to-digital converters. Some embodiments include a voltage controlled oscillator; a time-to-digital converter including a delay element array to output delayed versions of a signal and logic to generate a digital word that represents phase information of the signal based at least in part on the delayed versions; and a phase detector to generate a digital phase error based at least in part on the digital word. Other embodiments may be described and claimed.

Abstract: A delay adjusting circuit including a delay part in which delay elements of n+1 (n?2) stages are connected to each other in series, a first phase comparator for detecting whether a first edge that is a transition edge of a signal of an n?1-th stage of the delay part from a first logic level to a second logic level advances from a first reference signal edge that is a transition edge of a first reference signal from the first logic level to the second logic level, a second phase comparator for detecting whether a second edge that is a transition edge of a signal of an n+1-th stage of the delay part from the first logic level to the second logic level delays from the first reference signal edge, and a delay element adjusting part that corrects a second reference signal so that the first edge advances from the first reference signal edge in the first phase comparator and the second edge delays from the first reference signal edge in the second phase comparator, and that outputs a reference bias signal for adjust

Abstract: A semiconductor memory device includes a delay locked loop for achieving a delay locked state by correcting a phase difference between a reference clock and an internal delayed clock and for indicating the state that a larger delay amount than a maximum delay amount of a delay line is required, or a smaller delay amount than a minimum delay amount of delay line is required. A control unit resets the delay locked loop according to the state of the delay line.

Abstract: A delay locked loop (DLL) of a semiconductor device has a relatively small area and low current consumption while having a function of correcting a duty ratio. The semiconductor device includes a split unit configured to receive and split a reference clock to output a first clock corresponding to a first edge of the reference clock and a second clock corresponding to a second edge, a voltage generation unit configured to generate a first voltage corresponding to a duty ratio of the first clock and a second voltage corresponding to a duty ratio of the second clock, a voltage comparison unit configured to compare levels of the first and second voltages with each other, and a clock delay unit configured to receive one of the first and second clocks to delay the received clock of which delay amount is determined in response to an output signal of the voltage comparison unit.

Abstract: Deskewing method and apparatus, including: an up/down detection unit samples a received data signal and determines in which of first through third areas of the data signal the logic level of the data signal transitions by using the result of the sampling, a lower limit detection unit detects a lower limit of the first area if the logic level of the data signal transitions in the first area, an upper limit detection unit detects an upper limit of the third area if the logic level of the data signal transitions in the third area, a phase detection unit determines a delay amount according to the upper limit detected by the upper limit detection unit and the lower limit detected by the lower limit detection unit, a buffer unit delays the data signal by the delay amount determined by the phase detection unit.

Abstract: An apparatus for setting an operation mode in a DLL circuit generates a locking completion signal according to a level of a phase comparing signal obtained by comparing phases of a reference clock and a feedback clock. During three or more cycles of a pulse signal, it is determined whether a logic value of levels of the phase comparing signal is a specific combination, and the locking completion signal is selectively enabled.

Abstract: A DLL circuit includes: a phase determining circuit that compares phases of respective rising edges of CK and LCLK to generate a determining signal R-U/D; a phase determining circuit that compares phases of respective falling edges of CK and LCLK to generate a determining signal F-U/D; a first adjusting circuit that adjusts a position of an active edge of LCLKR based on the determining signal R-U/D; a second adjusting circuit that adjusts a position of an active edge of LCLKF based on the determining signal F-U/D; a clock generating circuit that generates LCLK based on LCLKR and LCLKF; and a stop circuit that stops an adjusting operation by the second adjusting circuit in response to an adjusting direction of the active edge of LCLKR being opposite to each other to an adjusting direction of the active edge of LCLKF.

Abstract: Delay locked loop circuits and methods are disclosed. In the embodiments, a delay locked loop may include a phase detector to detect a phase difference between a clock signal and a reference clock signal, and a charge pump that receives the detected phase difference. A low pass filter may filter an output from the charge pump. The delay locked loop may further include a delay line having a plurality of delay elements, the plurality of delay elements including a first selectable group and a second selectable group that is larger than the first selectable group. A first clock signal from the first group of delay elements may be provided to the phase detector to first synchronize the delay locked loop, and following the synchronization, a second clock signal from the second group may be employed to synchronize the delay locked loop.

Abstract: Methods and apparatus are provided for digital compensation of clock timing errors in a VCDL. Clock timing errors in a clock and data recovery system having a voltage controlled delay loop comprised of a plurality of delay elements are compensated for by evaluating a phase of data recovered from an input signal; generating one or more uncompensated clock phase adjustment values based on the phase evaluation; generating one or more compensation terms that compensate for a non-ideal delay for one or more of the delay elements; and determining an adjustment to one or more clock phases produced by the voltage controlled delay loop based on the uncompensated clock phase adjustment values and the one or more compensation terms. The one or more compensation terms can be subtracted from the uncompensated clock phase adjustment values to generate the adjustment to the one or more clock phases.

Abstract: A DLL circuit and a synchronous memory device perform stable operation in a power down mode although the entry and exit into/from the power down mode is repeated rapidly. The synchronous memory device operates in a normal mode and a power down mode. A delay locked loop (DLL) generates a DLL clock having frozen locking information when exiting the power down mode. A controller precludes phase update operation of the DLL when a predetermined time passes after entering the power down mode to thereby obtain a time margin for a phase update operation undertaken in the normal mode.

Abstract: A method of calibrating a PLL that includes forcing a control voltage input to a voltage controlled oscillator to be a reference voltage and setting a calibration divider coupled to receive an output clock signal from the voltage controlled oscillator such that the calibration divider utilizes one of a plurality of divisors that results in the output clock signal having a high frequency can substantially avoid overshoot and glitch problems associated with conventional PLL calibrations.

Abstract: A delay locked loop circuit includes a clock buffering block to generate first and second internal clocks corresponding to first and second edges of a source clock in response to a clock buffering control signal, respectively, wherein generation of the second internal clock is controlled by a duty correcting operation terminating signal and a delay locking signal, a delay locking block to compare phases of the first and second internal clocks with those of first and second feedback clocks, respectively, to enable the delay locking signal according to a delay locking and delay the first and second internal clocks as many as times corresponding to the comparison results, respectively, thereby outputting first and second delay locking clocks, a duty correcting block to mix phases of the first and second delay locking clocks, and a first signal generating block to generate the duty correcting operation terminating signal.

Abstract: Digitally controlled delay-locked loops can have a phase detector, control logic, and a delay chain. The control logic generates digital signals in response to an output signal of the phase detector. The delay chain generates a delay that varies in response to the digital signals. In some embodiments, the control logic maintains logic states of the digital signals constant in response to an enable signal to maintain the delay of the delay chain constant in a lock mode of the digitally controlled delay-locked loop. In other embodiments, the delay of the delay chain varies by a discrete time period in response to a change in logic states of the digital signals, and the maximum phase error between a phase of the reference clock signal and a phase of the feedback clock signal is less than the discrete time period when the digitally controlled delay-locked loop is in a lock mode.

Abstract: Disclosed herein is a wake-up circuit for a bias input of a circuit such as a slave DLL circuit, to allow it to be placed in a reduced power mode and be “awoken” (brought up to a control bias level) in a sufficiently small enough amount of time. The wake-up circuit couples a bias input node to a voltage level that is higher then the control bias level in response to a wake-up event, and then it couples the control bias node to the bias input node in response to their voltage levels being sufficiently close to one another.

Abstract: An integrated circuit includes a chain of delay elements, a first phase detector, and a controller. The chain of delay elements is configured to delay an input clock signal for providing an output clock signal phase shifted with respect to the input clock signal by a selected value. The first phase detector is configured to provide a common control signal to each delay element based on a phase difference between the input clock signal and a signal output from one of the delay elements to adjust a delay of each delay element. The controller is configured to provide an independent control signal to each delay element to individually adjust the delay of each delay element such that the delay of each delay element is equal.

Abstract: A register controlled delay locked loop (DLL) circuit, including: a phase comparator configured to compare phases of a source clock and a feedback clock with each other, and a clock delay circuit configured to delay a phase of an internal clock synchronized with a clock edge of the source clock in response to an output signal of the phase comparator. The clock delay circuit delays the phase of the internal clock using first delay units for a predetermined delay duration, and thereafter delays the phase of the internal clock using second delay units, the second delay unit providing a longer delay than the first delay unit. A delay replica model is configured to reflect actual delay conditions of the source clock in an output clock of the clock delay circuit to output the feedback clock.

Abstract: Apparatus, systems, and methods are disclosed that operate to delay a periodic input signal in one or more delay elements of a group of delay elements to generate a periodic output signal and to vary a power supply to the delay elements. Additional apparatus, systems, and methods are disclosed.

Abstract: A delay locked loop (DLL) circuit includes an initial operation setting unit configured to generate an initial operation signal in response to a reference clock signal and an operation start signal; a shift register configured to generate a delay control code in response to the initial operation signal, a phase comparison signal, and an initial setting code; a delay line configured to delay the reference clock signal or a feedback clock signal in response to the initial operation signal and the delay control code, thereby generating a plurality of unit delay clock signals; and an initial delay monitoring unit configured to generate the initial setting code in response to the reference clock signal and the plurality of unit delay clock signals.

Abstract: A delayed lock loop for preventing a stuck fail in a dead-zone includes a clock buffering block for generating a first and a second internal clock signals; a phase comparison block for delaying a feedback signal by a first predetermined value and for respectively comparing a phase of a delayed feedback signal and a phase of the feedback signal with a phase of the external clock signal; a clock selecting block for selecting one of the first and second internal clock signals based on one comparison result to thereby generate a selected internal clock signal; a stuck checking block for determining a delay value based on the other comparison result; a delay line block for delaying the selected internal clock signal by the delay value; and an output buffer for buffering an outputted signal from the delay line block to thereby generating a DLL clock signal.

Abstract: A delay locked loop (DLL) of a semiconductor device has a relatively small area and low current consumption while having a function of correcting a duty ratio. The semiconductor device includes a split unit configured to receive and split a reference clock to output a first clock corresponding to a first edge of the reference clock and a second clock corresponding to a second edge, a voltage generation unit configured to generate a first voltage corresponding to a duty ratio of the first clock and a second voltage corresponding to a duty ratio of the second clock, a voltage comparison unit configured to compare levels of the first and second voltages with each other, and a clock delay unit configured to receive one of the first and second clocks to delay the received clock of which delay amount is determined in response to an output signal of the voltage comparison unit.

Abstract: Upon a triggering event, a delay chain shifts data out at a higher rate than incoming packets and a processor controls bypassing circuitry to reduce the latency of hardware implementations of, for example, 802.11a OFDM receivers, with long delay chains. The signal processing algorithms used to recover symbol timing need a large number of samples stored in a delay chain, often consisting of pipelined registers. Such a delay chain introduces a large lag between the time samples have been acquired by the data converters and the time they are processed. This delay makes it difficult for higher level network layer implementations to meet the deadlines of 802.11a WLAN protocol. The proposed scheme implements dynamic reduction in the depth of the delay chain once timing recovery has been performed. A multi-step scheme achieves exponential reduction in the number of elements in the delay chain in every step.

Abstract: The delay locked loop circuit includes a charge pump circuit that may charge and discharge in response to an assertion of an up signal and a down signal, respectively. The delay locked loop circuit also includes a detection circuit that may assert the up signal indicating an occurrence of a transition of a first clock signal and may assert the down signal indicating an occurrence of a transition of a second clock signal. The delay locked loop circuit further includes a delay circuit that may provide a plurality of delayed clock signals and an additional delayed clock signal, each corresponding to a delayed version of the first clock signal. Further, a false lock circuit may provide a reset signal to the detection circuit dependent upon whether a predetermined number of successive clock edges associated with the delayed clock signals occur within a given clock cycle of the first clock signal.

Abstract: Some embodiments include a delay line configured to apply a delay to an input signal to provide an output signal; an input circuit configured to provide the input signal based on a first signal, such that the cycle time of the input signal is different from a cycle time of the first signal; an output circuit configured to provide a second signal based on the output signal, the second signal having a cycle time different from a cycle time of the output signal; and a controller configured to adjust the delay to control a timing relationship between the first signal and the second signal. Other embodiments are described and claimed.

Abstract: Disclosed herein is improved delay locked loop (DLL) initialization circuitry that alters the measurement used to initialize the variable delay line's delay (e.g., entry point or exit point) by using three clock phases: the DLL reference clock (input to the delay line), the reference clock as trimmed by a delay Tref, and the feedback clock as trimmed by a delay Tfb. By using these three phases at the appropriate time, the measurement is aware of the Tac trim for both positive (Tref) and negative (Tfb) trims. Specifically, measurement ‘start’ and ‘stop’ signals each pass through only one of delays Tref and Tfb, such that error in the measurement is a function of both Tref and Tfb. This improves the accuracy of the measurement such that additional shifting of the DLL is not necessary after initialization, and allows a wide trim range even for high clock frequencies.

Abstract: One embodiment provides an electronic system including a delay locked loop and a control circuit. The delay locked loop is configured to be enabled and update lock state data and to be disabled and store the locked state data. The control circuit is configured to periodically enable the delay locked loop in standby mode at an update interval and for an enable period. The control circuit controls the length of the update interval and the length of the enable period to adjust lock state acquisition time for the delay locked loop in exiting the standby mode.

Abstract: One aspect relates to a clock signal synchronizing device, in particular to a delayed locked loop (DLL) with capability to correct static duty-cycle offset and to filter clock-jitter. One aspect relates to a clock signal synchronizing method with capability to correct static duty-cycle offset and to filter clock-jitter. In accordance one aspect, there is provided a clock signal synchronizing device including a delay circuit having a variable delay time and delaying an incoming clock signal or a signal generated therefrom to output a delayed clock signal. Also included is a negator for inverting the delayed clock signal to output an inverted delayed clock signal. Also included is a delay control circuit for controlling the delay circuit to adjust the phase relation between the incoming clock signal and the inverted delayed clock signal and a phase interpolator.

Abstract: Embodiments of a multiphase generator with duty-cycle correction are generally described herein. In some embodiments, the multiphase generator comprises controllable delay stages arranged in series and dual-edge phase detector circuitry. The dual-edge phase detector circuitry may generate a control signal to adjust the delay provided by the delay stages based on corresponding rising edges and corresponding falling edges of same-state signals operated on by the delay stages. Other circuits, systems, and methods are described.

Abstract: A DLL circuit includes a delay line for delaying a clock signal, the delay line including a plurality of cascade-connected variable delay elements, the variable delay elements having a differential circuit structure in which a delay value thereof can be varied by a bias current, a first controller for setting the bias current, and a second controller for selecting an output-producing variable delay element from the plural its of the variable delay elements.

Abstract: The phase locked loop (PLL) with adjustable phase shift is described. The PLL includes a voltage controlled oscillator which is capable of generating multiple phase shifted output signals, and multiple phase detectors capable of determining the phase differences between the output signals and a reference clock. The PLL further includes a weighting device capable of weighting the phase differences and generating a control signal for the voltage controlled oscillator.

Abstract: A delay locked loop capable of preventing delay locking time from being increased, even if the operational environment fluctuates. The delay locked loop circuit includes a delay line for delaying and outputting a reference clock signal, a phase detection unit for detecting a phase difference between the reference clock signal and an output signal of the delay line and then outputting a phase detection signal and a first delay mode decision signal, a control unit for outputting a delay control signal to control the delay line according to the phase detection signal and a second delay mode decision signal, and an error decision unit for detecting an error of the first delay mode decision signal according to the delay control signal and the output signal of the delay line and outputting the second delay mode decision signal according to a result of the error detection.

Abstract: A delay locked loop (DLL) circuit for a synchronous dynamic random access memory (SDRAM) is provided. If a locking state is broken due to an external change such as a change of tCK or power supply voltage, indicating that a delay of a delay replication modeling unit involved in a DRAM is abruptly changed, the locking state can be recovered within a certain time, e.g., 200 tCK, by creating an internal reset signal in the DLL circuit by a circuit that monitors the state and then conducting a phase update using a rough delay value.

Abstract: A delay line including a phase detector having two inputs and one output. The first input of the phase detector is connected to an input of the delay line. The second input of the phase detector is connected to an output of the delay line. The output of the phase detector is connected to a control circuit which controls current flow at a control node to produce a control voltage at the node. A voltage-controlled delay unit is responsible to the control voltage to control a delay applied to a signal at an input of the delay line.

Abstract: Delay lock loop circuits are described, which may include two or more delay stages that each includes a plurality of selectable delay elements. A reference signal drives an input of the first delay stage, which provides a first output. The first output drives an input of the second delay stage, which provides a second output. The circuits further include a first selector register that is associated with the first delay stage. A value maintained in the first selector register determines a number of the selectable delay elements utilized in the first delay stage. The circuits further include a second selector register associated with the second delay stage. A value maintained in the second selector register determines a number of the selectable delay elements utilized in the second delay stage. Modification of the values maintained in the first and second selector registers are synchronized to the first and second outputs, respectively.

Abstract: A DLL circuit includes a delay line (CDL) (10) that delays a clock signal at a relatively coarse adjustment pitch, a delay line (FDL) (20) that delays the clock signal at a relatively fine adjustment pitch, and phase detecting circuits and counter control circuits that control delay amounts of the delay lines (10, 20). The counter control circuits control the delay line (10) by a linear search method, and control the delay line (20) by a binary search method. As a result, even when the number of bits of the count signal for adjusting the delay line (20) is increased, a delay amount can be determined at a high speed.

Abstract: A duty cycle correction circuit and a delay locked loop circuit including the same are capable of reducing area and power consumption of a circuit. The delay locked loop circuit includes a delay locked loop unit, a delay controller, a duty cycle ratio correction circuit, and a duty cycle ratio detector. The delay locked loop unit outputs an internal clock by delaying an external clock in order to compensate a clock skew. The delay controller outputs a delay internal clock by delaying the internal clock in response to correction signals. The duty cycle ratio correction circuit outputs an internal correction clock by increasing or decreasing a high level section of the internal clock according to the correction signals. The duty cycle ratio detector outputs the correction signals in accordance with a duty cycle ratio of the internal correction clock.

Abstract: A delay locked loop circuit for compensating for a phase skew of a memory device includes a first delay locking unit configured to delay an external clock of the memory device by a first amount of delay to output a first internal clock, a second locking unit configured to delay the external clock by a second amount of delay to output a second internal clock, the second amount of delay being greater than the first amount of delay, and a selecting unit configured to select one of the first internal clock and the second internal clock as an internal clock of the memory device.

Abstract: Memories, multi-phase clock signal generators, and methods for generating multi-phase duty cycle corrected clock signals are disclosed. For example, one such clock signal generator includes a delay-locked loop having a first multi-tap adjustable delay line configured to delay a reference signal to provide a plurality of clock signals having different phases relative to the reference clock signal. A periodic signal generated by the delay-locked loop is provided to a second multi-tap adjustable delay line as an input clock signal. Clock signals from taps of the second multi-tap adjustable delay line are provided as the multi-phase duty cycle corrected clock signals.