Abstract: The tension between fmax and Tco in a specialized processing block of a programmable integrated circuit device can be reduced by providing variable delays on the clock inputs of the pipeline registers within the specialized processing block. This allows the introduction of beneficial skew that allows slower functions to be performed within the specialized processing block rather than outside the block, thereby reducing Tco, without slowing down the clock—i.e., without reducing fmax. This technique may also apply to other specialized blocks such as memory.

Abstract: A frequency adjusting method of a CDR circuit and apparatus thereof are provided. The adjusting method is applied to a receiver apparatus connected to an outer apparatus. The outer apparatus, after actuated, sends out an outer data signal to the receiver apparatus according to its operational frequency and a PLL of the receiver apparatus outputs a transmitter clock according to an operational frequency of the receiver apparatus. The CDR circuit of the receiver apparatus generates a receiver clock according to the outer data signal. The CDR circuit is set in a phase mode such that the receiver clock follows transmitting frequency of the outer data signal. Then, a difference between frequencies of the receiver clock and the transmitter clock is checked. If the difference is larger than a threshold value, an operational frequency of the outer data signal is reduced.

Abstract: A clock selector operative on two clocks operating on different domains and responsive to a SELECT input provides a transition from a first clock to a second clock, and from a second clock to a first clock with a dead zone therebetween. The delay is provided by a doublet register having a first register coupled to a second register, the two registers operative on one of the clock domains. Additionally, a clock selector is operative on two clocks which are each accompanied by a clock availability signal where the state machine provides a variety of states to create a dead zone between selections, and to bring the state machine to a known state until a clock signal is again available.

Abstract: A phase recombination circuit includes a first phase input and a first one-shot pulse generator adapted to receive the first phase input and produce a first signal to pull a signal to a first state. The phase recombination circuit also includes a second phase input in phase relationship with the first phase input, and a second one-shot pulse generator adapted to receive the second phase input and produce a second signal to pull a signal to a second state.

Abstract: A digital pulse generator including a fractional delay filter is provided as having a plurality of step response functions that can be selected on a sample by sample basis by selection of filter coefficients. The step response functions are all identical but each have different group delay. Responsive to an input waveform having leading and trailing edges aligned with a system clock, the fractional delay filter can output the impulse responses as a pulse waveform having respective leading and trailing edges delayed by different respective fractions of a signal clock cycle from the respective leading and trailing edges of the input waveform. The pulse waveform as output can thus have desired pulse width and desired period of repetition with finer edge placement resolution of improved accuracy.

Abstract: A pulse edge selection circuit includes an input stage which selects and passes one clock from among a plurality of clocks and an output stage which outputs the clock to an edge detection circuit. The output stage has a combination of a plurality of NOR gates and a plurality of NAND gates, which are connected alternately, both the NOR gates and NAND gates having a plurality of input terminals. If the edge detection circuit is a type which detects falling edges of clocks and generates a pulse which rises on the falling edge of a first clock and falls on the falling edge of a second clock, a NOR gate is used as an output gate which outputs the first clock and the second clock. On the other hand, if a pulse is generated on rising edges, a NAND gate is used as an output gate.

Abstract: An input circuit is disclosed. The input circuit can include a cross voltage generating block that can be configured to perform charge-sharing on a pair of input signals whose phases are opposite to each other and generate a cross voltage, and an input buffer block that can be configured to buffer the pair of input signals at a voltage level corresponding to a voltage level of the cross voltage and generate an output signal.

Abstract: A phase generating apparatus generates an output clock having a desired phase according to a digital signal. The apparatus includes a phase selecting unit and a phase generating unit. The phase selecting unit selects one of a plurality of input clocks according to a portion of bits of the digital signal to generate a reference clock. Each of the input clocks respectively has a difference phase. The phase selecting unit divides the frequency of the reference clock, and selectively delays the frequency-divided reference clock according to another portion of bits of the digital signal to generate the output clock.

Abstract: Disclosed is a phase clock generator. The phase clock generator can include transistors and a buffer. The transistors are connected between a power line and a grounding line and are provided in a form of a 4×N matrix to receive a plurality of phase-delayed signals through their gate terminals. Four transistors can form a unit column between the power line and the grounding line. From ground line to power line, the first two transistors of the unit column provide a pair of NMOS transistors, and the second two transistors provide a pair of PMOS transistors. The buffer is connected to a line, which is provided between the pair of the NMOS transistors and the pair of the PMOS transistors forming the unit column, to transmit a clock signal.

Abstract: A circuit for glitchless switching between asynchronous clocks includes a select circuit and enable circuits. The select circuit receives a selection signal for selecting one of the clock input signals and to generate enabling signals for activating the corresponding enable circuits on the basis of the current output signal. The feedback logic in the circuit ensures that at any given instance only one of the clock input signals is outputted so as to avoid the formation of glitches. The circuit can be applied to switches between any number of asynchronous clocks.

Abstract: There is provided a signal generating apparatus including: a multiphase oscillating portion for generating a number of base signals having the same frequency and a predetermined phase difference of which the signal level transitions between a first level and a second level, and where periods during which the signal level of any given base signal is at the first level and the signal level of the next base signal having the predetermined phase delay relative to the given base signal is at the first level overlap; and a transition time point changing portion for generating a pulse signal by changing the time point when each base signal transitions from the first level to the second level to a time point before the next base signal transitions from the second level to the first level.

Abstract: A phase recombination circuit includes a first phase input and a first one-shot pulse generator adapted to receive the first phase input and produce a first signal to pull a signal to a first state. The phase recombination circuit also includes a second phase input in phase relationship with the first phase input, and a second one-shot pulse generator adapted to receive the second phase input and produce a second signal to pull a signal to a second state.

Abstract: A clock circuit which may include a first clock input for receiving a first clock signal and a second clock input for receiving a second clock signal. A clock calibration unit is connected to the first clock input and the second clock input. The calibration unit may calibrate the second clock signal relative to the first clock signal. The clock calibration unit may have a calibration output for outputting a calibrated clock signal. The clock circuit may include a switch unit connected to the first clock input and the calibration output. The switch unit can select a selected clock signal selected from the first clock signal and the calibrated signal. The switch unit has a switch output for outputting the selected clock signal. A switch control unit is connected to the switch unit for controlling which signal is selected based on a selection criterion and a clock circuit output is connected to the switch unit for outputting the selected clock signal.

Abstract: A programmable clock control circuit includes a base block, a chop block, and a pulse width variation block coupled between the chop block and the base block that receives the chop block output and provides a pulse width variation output to the base block. The pulse width variation block is programmable to vary the chop block output to provide at least three different output pulse widths. The circuit also includes a clock delay block coupled an output of the base block to delay the output pulse and having a clock signal output.

Abstract: An apparatus and method are disclosed for generating one or more clock signals. A clock signal is generated based on pattern signals and a reference clock signal. When the reference clock signal transitions high, the state of a first pattern signal is output, and when the reference clock signal transitions low, the state of a second pattern signal is output. Successive states of the first and second pattern signals, selected according to the reference clock signal, provide the generated clock signal.

Abstract: A high-level period of each of n first pulse signals partially or wholly overlaps a period during which all of n second pulse signals are at the low level. A high-level period of each of the n second pulse signals partially or wholly overlaps a period during which all of the n first pulse signals are at the low level. Each of n first drive transistors includes a source connected to a ground node, a drain connected to a first node, and a gate receiving a corresponding one of the first pulse signals. Each of n second drive transistors includes a source connected to the ground node, a drain connected to a second node, and a gate receiving a corresponding one of the second pulse signals. A current mirror circuit allows a current corresponding to a current flowing through the second node to flow through the first node.

Abstract: Techniques for the design and use of a digital signal processor, including for processing transmissions in a communications system. Reduced glitch occurs in switching from a first clock input to a second clock input driving a clock multiplexer. The clock multiplexer receives a first clock input and provides a clock output and determines a low phase output level in the clock output. For a limited period of time, a low phase output level is forced. The clock multiplexer receives a second clock input and determines a low phase input level in the second clock input signal. Switching to providing the clock output in response to the second clock input occurs during the low phase input level in the second clock input signal. Then, the output of the clock multiplexer follows the phase level of the second clock signal.

Abstract: Clock switch-over circuits and methods provide clock signals to clock routing networks. According to one embodiment, a multiplexer selects between a first clock signal and a second clock signal in response to a switch select signal received from a control circuit. A storage circuit stores an enable signal in response to an output clock signal of the multiplexer. A logic circuit transmits the output clock signal of the multiplexer to a clock routing network in response to the enable signal from the storage circuit. At least one signal is transmitted from the clock switch-over circuit to the control circuit.

Abstract: A clock signal generation apparatus includes a clock signal generation circuit generating a plurality of clock signals, and a self-test circuit measuring a phase difference of one pair of clock signals. The self-test circuit includes a clock signal selection circuit selecting the pair of clock signals among the plurality of clock signals, a phase detection circuit generating a phase difference pulse signal, a test signal generation circuit generating a test signal having a frequency which is lower than the phase difference pulse signal, and a counter circuit counting the pulse number of the test signal.

Abstract: The present invention is applicable to an electronic device including a master, a slave, a bus coupling the master and the slave and a clock generator for providing a system clock to the master and slave. The clock generator determines whether the received data is correct on a cycle-by-cycle basis. The clock generator suppresses an edge of a next clock cycle of the system clock signal if the data is not to be correct. The clock generator allows the edge of a next clock cycle of the system clock signal if the data is correct.

Abstract: An apparatus for generating a reference clock for a DLL circuit includes a buffering unit configured to buffer an external clock so as to generate a first reference clock and a second reference clock, and to invert the second reference clock so as to generate a negative second reference clock. A duty cycle compensating unit generates a reference clock from the first reference clock and the negative second reference clock.

Abstract: Clock multiplexing techniques generate an output clock signal by detecting edges of a selected input clock signal and toggling the output clock signal based on detected edges of the selected input clock signal. Toggle signals are generated based on detected edges of the selected input clock signal. Toggle signals are used to control when the output clock signal is to toggle high or low. A latch holds the state of the output clock signal in its current state until changed by receipt of a toggle signal. Switching from use of a first clock signal to use of a second clock signal occurs regardless of whether the first input clock is operating. A delay is introduced that prevents glitches in the output clock signal that are less than one half clock period of the next selected input clock signal in duration.

Abstract: Disclosed is an SSC controller that exercises control to supply a control signal to a phase interpolator which receives an input clock signal and varies the phase of an output clock signal in accordance with the control signal, and to frequency-modulate the output clock signal. In an SSC controller, a counting operation control circuit outputs a counting operation control signal that controls count enable and disable. A p-counter receives a frequency-divided clock signal from a frequency divider and counts the signal when the counting operation control signal from the counting operation control circuit indicates count enable. Upon counting up to a predetermined first value, the counting operation control circuit generates a first output signal and sets its count value to zero. When the counting operation control signal indicates count disable, the p-counter stops counting.

Abstract: An apparatus for generating a pulse having a pulse width substantially independent of process variation in resistive and capacitive values. The apparatus includes a PTAT current source to generate a first current to charge a capacitor to produce a first voltage; a ?VGS current source to generate a second current through a resistor to produce a second voltage V2; a comparator to generate the pulse in response to the first and second voltages; and a circuit to enable the charging and discharging of the capacitor. The use of the distinct current sources (e.g., PTAT and ?VGS) enables the pulse generator to be configured substantially process independent of resistive value. The use of a MOSFET capacitor for the capacitor enables the pulse generator to be made substantially process independent of capacitive value. An additional bandgap current source in parallel with the ?VGS current source reduces the pulse width dependency on temperature.

Abstract: Various embodiments of a semiconductor integrated circuit. According to one exemplary embodiment, a semiconductor integrated circuit includes a multi-phase clock generator that is configured to generate a multi-phase internal clock; a first edge combining unit that is configured to generate a first output clock having a first frequency by combining rising edges of clocks included in the internal clock, and transmit the first output clock to a first port; and a second edge combining unit that is configured to generate a second output clock having a second frequency by combining rising edges of clocks included in the internal clock, and transmit the output clock to a second port.

Abstract: A start-up circuit receives a start-up signal instructing start-up of an equipment mounted with the circuit, and executes a predetermined sequence when start-up is instructed by the start-up signal. An oscillator generates a clock signal. A sequence circuit receives the start-up signal and a clock signal output from the oscillator, measures time by counting the clock signal when the start-up signal transits to a predetermined level, and executes a predetermined event at a predetermined timing. The oscillator operates for a period where the start-up signal is at the predetermined level if the start-up signal is at the predetermined level during the period the power key of the equipment mounted with the circuit is being pushed.

Abstract: In a synchronous semiconductor device (250), an input/output control circuit is formed of a clock input I/O (260), a clock control signal input I/O (270) and a signal change detection circuit (280). The clock input I/O (260) includes a first input buffer (264) having a large threshold, a second input buffer (266) having a small threshold and an input selector (268). The signal change detection circuit (280) controls the input selector (268) so that a first input from the first input buffer (264) is normally selected and a second input from the second input buffer (266) is temporarily selected only when the signal change detection circuit (280) detects that a logic level of a clock control signal (279) is changed from a non-activated level to an activated level.

Abstract: A mobile communication device includes an analog clock and a digital clock circuit. The analog clock circuit is configured to generate an oscillating output. The digital clock circuit is configured to generate a digital clock output having a frequency that is substantially equal to the frequency of the oscillating output.

Abstract: Phase mixers, clock signal generators, memories and methods for providing an output signal having a phase relative to the phase difference of input clock signals are disclosed. One such phase mixer includes a phase mixer circuit having inputs and an output. The phase mixer is configured to receive a plurality of input clock signals and generate an output clock signal at the output having a phase relative to the plurality of input clock signals. The phase mixer further includes an adjustment circuit coupled to the phase mixer circuit. In some phase mixers, a control circuit coupled to the phase mixer circuit and the adjustment circuit is included. The control circuit is configured to generate a control signal based on the input signals to adjust an electrical load-to-drive ratio of the phase mixer.

Abstract: Oscillator system and method thereof. The oscillator system includes a first voltage-to-current converter configured to receive a first voltage and generate a first current based on at least information associated with the first voltage, and a second voltage-to-current converter configured to receive a second voltage and generate a second current based on at least information associated with the second voltage. Additionally, the oscillator system further includes a current-mode N-bit digital-to-analog converter configured to receive at least the second current and a first clock signal and to generate a third current based on at least information associated with the second current and the first clock signal. N is a first integer. The first clock signal is associated with a first clock frequency corresponding to a first clock period. Moreover, the oscillator system further includes a current comparator coupled to the first voltage-to-current converter and the current-mode N-bit digital-to-analog converter.

Abstract: A wireless communication device is described having a transmitter that generates electromagnetic interference when operating in a transmit mode. The wireless communication device comprises a clock circuit including a first clock element configured to generate a first clock output, and a second clock element configured to generate a second clock output. Also included is a controller configured to switch between the first clock output and the second clock output when the transmitter is operating in the transmit mode.

Abstract: A clock generator includes a first input end and a second input end. The first input end is capable of receiving a first clock signal including a first state transition and a second state transition defining a first pulse width. The second input end is capable of receiving a second clock signal having a third state transition. A time period ranges from the first state transition to the third state transition. The clock generator can compare the first pulse width and the time period. The clock generator can output a third clock signal having a second pulse width ranging from a fourth state transition to a fifth state transition. The fifth state transition of the third clock signal is capable of being triggered by the second state transition of the first clock signal or the third state transition of the second clock signal depending on the comparison of the first pulse width and the time period.

Abstract: A semiconductor integrated circuit (10D) for receiving a parallel data signal and a first clock signal and outputting a serial data signal and a second clock signal, wherein a first clock generation circuit (15) produces a third clock signal obtained by multiplying the first clock signal by X/Y. A second clock generation circuit (11) has a variable transmission characteristic, and produces a fourth clock signal obtained by multiplying the third clock signal by N. A parallel/serial conversion section (12) converts the parallel data signal, which has been converted by a scaler (16), to the serial data signal in synchronism with the fourth clock signal. A frequency divider (13) produces a fifth clock signal obtained by dividing a frequency of the fourth clock signal by N. A selector (14) selectively outputs, as the second clock signal, one of the third and fifth clock signals.

Abstract: A first plurality of clock signals including a first clock signal and a second clock signal is received, the first and second clock signal out of phase with each other. A second plurality of clock signals comprising a third clock signal and a fourth clock signal is received, the third and fourth clock signals out of phase with each other. A plurality of enable signals are received. A fifth clock signal is determined based on the first plurality of clock signals and the plurality of enable signals. A sixth clock signal is determined based on the second plurality of clock signals and the plurality of enable signals. A seventh clock signal is determined based on the fifth clock signal and the sixth clock signal.

Abstract: An apparatus for supplying an overdriving signal in a memory apparatus. The apparatus includes: a voltage detecting block that outputs a plurality of detection signals according to the level of an external voltage, and a pulse generator that outputs the overdriving signals having different pulse widths according to the plurality of detection signals.

Abstract: The present invention relates to a method and an apparatus, during a phase switching process, for choosing all of outputted phases upon the clock phases devoid of phase switching so as to avoid glitches during clock switching. Compared with the conventional approach for removing glitches by controlling a clock switching sequence, an improvement of a phase rotator is further disclosed in the present invention, which eliminates the glitches of the outputted phase clock so as to realize a glitch-less phase switching in a phase interpolation circuit.

Abstract: A method and apparatus to implement clock signal adaptation is provided to characterize an input clock signal that is to be adapted and in response, generate adaptation updates at each subsequent clock cycle of the input clock signal. In a first embodiment, clock signal adaptation occurs through duty cycle correction (DCC) to substantially achieve a 50% duty cycle. In an alternate embodiment, clock signal adaptation occurs through a multiplication operation that is applied to the clock signal to be adapted, whereby the multiplication operation is parameterizable to allow odd/even multiplication. In an alternate embodiment, clock signal adaptation occurs through a phase-shift operation that is applied to the clock signal to be adapted, whereby the phase-shift operation is parameterizable to allow all possible fractions and percentages of phase shifts.

Abstract: A pulse generator is provided that includes: a current source, a source follower whose output controls the gate of a FET and a differential stage whose input voltage consists of inverting square waves and its output voltage consists of extremely narrow pulses widths, for example, of 30 to 40 ps and amplitude of 1.5 Volts.

Abstract: In a device for generating a clock signal having a desired phase from input multi-phase clock signals, an intermediate clock generator generates, by using one of the input multi-phase clock signals as a reference clock signal, multi-phase intermediate clock signals in which one cycle is equal to a plurality of cycles of the reference clock signal. A first phase selector selects one of the multi-phase intermediate clock signals. A second phase selector selects one of the multi-phase clock signals. A latch circuit latches the intermediate clock signal selected by the first phase selector with the clock signal selected by the second phase selector.

Abstract: A duty cycle correction circuit apparatus includes a flip-flop, a feedback unit connected between an input node and an output node of the flip-flop to invert an output signal of the flip-flop and to output the inverted signal as an output signal of the feedback unit, and a selection unit to select and output one of a first clock signal and a second clock signal to the flip-flop in response to the output signal of the feedback unit, wherein the first clock signal has a half-period phase difference with respect to the second clock signal. Using clock signals with a half-period phase difference therebetween and a simple digital circuit, the duty cycle correction circuit can correct a duty ratio to 50:50 regardless of an initial condition.

Abstract: An internal clock generator, system and method of generating the internal clock are disclosed. The method comprises detecting the level of an operating voltage within the system, comparing the level of the operating voltage to a target voltage level and generating a corresponding detection signal, and selecting between a normal clock and an alternate clock having a period longer than the period of the normal clock in relation to the detection signal and generating an internal clock on the basis of the selection.

Abstract: An apparatus for generating a reference clock for a DLL circuit includes a buffering unit configured to buffer an external clock so as to generate a first reference clock and a second reference clock, and to invert the second reference clock so as to generate a negative second reference clock. A duty cycle compensating unit generates a reference clock from the first reference clock and the negative second reference clock.

Abstract: A duty detector includes a clock converter, a hold pulse generator, a first logic operator, and an up/down counter. The clock converter receives a clock signal to generate an up clock signal and a down clock signal having phases opposite to each other. The hold pulse generator generates a hold pulse signal that is deactivated during a counting interval corresponding to first through (N?1)-th period intervals of the clock signal and is activated during a holding interval corresponding to an N-th period interval. The first logic operator outputs a counting clock signal by performing a first logic operation on the hold pulse signal and a sampling clock signal. The up/down counter determines a logic level of the up clock signal and a logic level of the down clock signal at an edge timing of the counting clock signal, increases or decreases a counting value in response to the determination result, and outputs duty information of the clock signal, based on a final counting value.

Abstract: A frequency-control circuit, which is configured to receive a first signal having a first untuned frequency from a first oscillator, and to alter one or more pulses of the first signal to tune an output frequency of an output clock signal to have an average frequency at the desired target frequency. In some embodiments, the two oscillators of intentionally different frequencies are periodically switched at a duty factor, which is dependent on an absolute temperature, to generate a calibrated, precise, and temperature-stable clock.

Abstract: A semiconductor integrated circuit includes a voltage supplying unit that supplies a first regulated voltage and a second regulated voltage by using a first reference voltage and a second reference voltage, respectively, and a clock buffer unit that supplies an output clock clocking within a range of the first regulated voltage and the second regulated voltage.

Abstract: A clock generator (622) includes a first circuit (812) and a second circuit (814). The first circuit (812) includes a first clock input configured to receive a first clock signal at a first frequency, a second clock input configured to receive a second clock signal at the first frequency, and an output. The second clock signal is out-of-phase with the first clock signal. The second circuit (814) is coupled to the first circuit (812) and includes a mode signal input configured to receive a mode signal. The output of the first circuit (812) is configured to provide a generated clock signal whose effective frequency is based on the first and second clock signals and the mode signal.

Abstract: The disclosure includes a latch structure and self-adjusting pulse generator using the latch. In an embodiment, the system includes a first latch and a pulse generator coupled to provide a timing signal to the first latch. The pulse generator includes a second latch that has characteristics matching the first latch.

Abstract: A digital signal multiplexor and multiplexing method are provided with which switching between different input signals is achieved without producing glitches in the output signal, even in the event of one or more of the input signals stopping and starting at unknown times.

Abstract: The present invention relates to a control method for the operation modes of an oscillator and the apparatus thereof, for which the method and the apparatus can be applied to the electronic circuits with multi-operation modes of the oscillator so as to correctly choose the desirable oscillator operation mode. Furthermore, an oscillator checking circuit sets up the oscillation mode automatically and judges if the oscillator operates properly. Hence, there is no need for the user to set up the oscillator operation mode manually.

Abstract: An apparatus and method are disclosed for generating one or more clock signals. A clock signal is generated based on pattern signals and a reference clock signal. When the reference clock signal transitions high, the state of a first pattern signal is output, and when the reference clock signal transitions low, the state of a second pattern signal is output. Successive states of the first and second pattern signals, selected according to the reference clock signal, provide the generated clock signal.