Abstract: A computer of the present invention contains: a CPU; plural peripheral devices controlled by the CPU; a data transmission bus between the CPU and the peripheral devices and between the peripheral devices; and a clock signal source for supplying clock signals for CPU operation and data transmission. The clock signal source contains a PLL synthesizer, and two clock signals (one for the CPU and the other for the bus) are outputted from the PLL synthesizer to stop unnecessary signals (other than the clock signals) from being produced.

Abstract: A circuit arrangement for generating non-overlapping clock phases including a first circuit, a second circuit, and a multiplexer. The first circuit combines two input signals to form an output signal, and a first input provides for application of a common clock signal. The second circuit combines two input signals to form an output signal, and a first input provides for application of the common clock signal. The multiplexer has a first input connected to an output of the first circuit, a second input connected to an output of the second circuit, and an output connected to a second input of each of the first and second circuits, and has a third input that switches between the first and second inputs of the multiplexer for application of the clock signal. A plurality of non-overlapping clock phases are provided by output signals of the first and second circuits and of the multiplexer.

Abstract: Embodiments of the present invention provide for generating a sampled differential pattern signal with reduced jitter. In one embodiment of the present invention, a seed frequency generator provides a differential seed frequency signal. The differential seed frequency signal is converted to a single ended seed frequency signal by a differential-to-single ended converter. The pattern generation logic utilizes the single ended seed frequency signal to generate single ended pattern signals. Single ended-to-differential samplers then generate a sampled differential pattern signal by sampling the single ended pattern signal according to the differential seed frequency signal.

Abstract: A power saving hierarchical clock gating circuit includes a first level clock gate, a plurality of second level clock gates connected to the first level clock gate, and a plurality of third level clock gates for selectively providing a clock signal to a functional block. Each third level clock gate is connected between a second level clock gate and a register, or other low level device, of the functional block for selectively providing the clock signal to the register. Accordingly, the clock signal is conveyed from the first level clock gate through a second level and a third level clock gate to a register when the corresponding first, second, and third level clock gates are activated by associated decision logic.

Abstract: Several local clock buffers are disclosed, each including an input section and an output section. The input sections are substantially identical, and include control logic and gating logic. The control logic produces a gating signal dependent upon multiple control signals and a time-delayed global clock signal. The gating logic produces an intermediate clock signal dependent upon the global clock signal and the gating signal. The output section produces at least one local clock signal dependent upon the intermediate clock signal. In one embodiment, the output section produces a first local clock signal dependent upon the intermediate clock signal and a second local clock signal dependent upon the first local clock signal. In another embodiment, the gating logic produces the intermediate clock signal dependent upon the global clock and gating signals and a feedback signal. The output section produces the feedback signal and one or more local clock signals.

Abstract: A clock system for providing a high-speed clock signal to a plurality of integrated circuits is disclosed. The clock system includes an analog signal generator for producing a periodic analog signal of a predetermined frequency and fanout circuitry. The fanout circuitry is coupled to the analog signal generator and includes a transmission line and an RF coupler. The system further includes a plurality of receivers. Each receiver has reference signal input circuitry and clock signal input circuitry. Both the reference signal circuitry and the clock signal circuitry are receptive to coupling locally generated common mode noise. The clock signal circuitry is disposed proximate the RF coupler to provide an RF coupling therebetween.

Abstract: A method for operating a master latch and a slave latch coupled to the master latch includes the steps of attempting to operate the master latch and the slave latch in a first mode in which (1) the master latch is held in an open condition; and (2) the slave latch is pulsed so as to latch data passed through the open master latch. If the master latch and the slave latch do not operate in the first mode, the master latch and the slave latch are operated in a second mode in which (1) a first clock signal is employed to latch data with the master latch; and (2) a second clock signal is employed to latch data latched by the master latch with the slave latch.

Abstract: A system and method for multiple-phase clock generation is disclosed. In one embodiment, a multiple-stage voltage controlled oscillator (“VCO”) transmits a plurality of clock phases to a clock divider circuit which produces the desired number of clock phase outputs. The clock divider circuit in this embodiment includes a state machine, e.g., a modified Johnson counter, that provides a plurality of divided down clock phases, each of which is connected to a separate modified shift register. Each modified shift register contains D-type flip-flops and each D-type flip-flop provides a separate clock phase output. In one embodiment the number of clock phase outputs of the multiple-phase clock is a function of the number of VCO clock phases times the number of desired states in the modified Johnson counter.

Abstract: According to some embodiments, non-overlapping clocks are to be generated.

Abstract: A conditional clock buffer circuit includes a clock output and is coupled to receive a clock input and a condition signal. The conditional clock buffer circuit includes a first circuit coupled to receive the clock input and a second circuit coupled to receive the clock input and the condition signal. The first circuit is configured to generate a first state on the clock output responsive to a first phase of the clock input. The second circuit is configured to conditionally generate a second state on the clock output responsive to the condition signal during a first portion of a second phase of the clock input. In one implementation, one or more of the conditional clock buffer circuits may be included in a clock tree. The clock tree may also include one or more levels of buffering.

Abstract: The clock-generating circuit for generating a clock signal, includes a ring oscillator having an odd number of inverters connected in a ring configuration. The ring oscillator is activated to generate a clock signal when an activating signal is at a first level and is de-activated to cease generation of the clock signal when the activating signal is at a second level. A latch circuit is connected to an output node of the ring oscillator, and holds a level of the output node of the ring oscillator in response to transition of the activating signal from the first level to the second level. When the activating signal is lowered from the H level to the L level, the level of the clock signal is latched such that generation of a glitch in the clock signal will be prevented from occurring.

Abstract: A clock signal supply circuit includes a sine wave oscillator and a circuit operating with an oscillation signal, as a clock signal, outputted from the sine wave oscillator, a waveform shaping circuit is provided correspondingly to the circuit, the circuit and the waveform shaping circuit are constructed in the same circuit unit, and the oscillation signal is converted into a rectangular wave by the waveform shaping circuit in the circuit unit and is supplied to the circuit.

Abstract: There is provided a pulse generator capable of generating a pulse with a reduced number of transistors that toggle in response to a clock signal, thereby reducing power consumption. The pulse generator includes a plurality of unit cells, wherein an nth unit cell (n is a natural number more than 2) generates a pulse in response to a divided-by-N clock signal (N is a natural number), a signal output from an (n−1)th unit cell and a signal output from an (n+1 )th unit cell. The nth unit cell is reset or generates the pulse whose width is equivalent to the width of the clock signal, according to the logic level of the signal output from the n+1th unit cell.

Abstract: A circuit, system, and method are provided for regulating the mark-to-space ratio of a clocking signal. In instances where the mark-to-space ratio is targeted at 1:1 (i.e., a 50% duty cycle), then a regulated signal is formed which will produce a 50% duty cycle whenever that regulated signal is forwarded to a buffer which will produce a duty cycle other than 50% if the input signal were not regulated. The regulated signal is derived from a feedback circuit which will take into account the periodic nature of the clocking signal and whatever threshold skews might be attributable to the clock buffer. The feedback signal derives its input from a tap connected to receive the clocking signal from an output of the buffer, and the tap forwards that clocking signal to switching transistors which impute the periodic clocking frequency onto a threshold skewed output which will then form the regulated signal. Any skew resulting from the oscillator will not be passed to the node which bears the regulated signal.

Abstract: A clock controlling circuit and method for eliminating the delay difference in the entire clock propagation line. Circuit scale is reduced as compared to a case of using a PLL or DLL circuit. A timing averaging circuit 10 is fed with clocks from a position on a forward route 111 of a direction-reversed clock propagation path, adapted for being fed with input clocks at its one end, and from a position on a return route 112 corresponding to the position on the forward route 111. The timing difference between these clocks is averaged to output an averaged timing difference.

Abstract: An improved clocking circuit is provided for generating a half swing clock. Previous circuit operations required an additional supply voltage rail (Vdd/2), but the preferred embodiment exploits charge sharing to generate a half swing clock with less power and without the additional supply voltage rail. To drive clock nodes to Vdd/2, a shunt transistor is opened, and the fully charged clock node shares its charge with the fully discharged clock node. When capacitances have been properly matched, both nodes will settle at Vdd/2.

Abstract: An apparatus and method for compensating skew across a plurality of data interfaces includes using a recovered clock signal at an incoming clock rate to regulate output from a deskew interface. The recovered clock is drawn from one of the data interfaces and the data from all the data interfaces is deskewed to the recovered clock signal. A deskew buffer is provided for each data interface. Link logic may also be run in accordance with the recovered clock signal. Alternatively, the link logic may run at a local clock rate and an elastic buffer is coupled between the deskew interface and the link logic.

Abstract: A method and apparatus for driving a differential clock signal involves a first power supply, second power supply, first clock path, and second clock path. The differential clock driver is arranged to receive a differential clock signal from the first clock path and generate a differential clock signal on the second clock path. The generated differential clock signal has a maximum voltage potential less than a maximum voltage potential of the first power supply voltage potential and a minimum voltage potential greater than a minimum voltage potential of the second power supply voltage potential.

Abstract: A clock generating circuit of a semiconductor integrated circuit device includes a plurality of stages of frequency-dividing circuits connected in series, of which a first stage receives a reference clock signal, each frequency-dividing circuit requiring no reset signal; and a plurality of buffers respectively transmitting a reference clock signal and output clock signals of the plurality of frequency-dividing circuits to an internal circuit of the semiconductor integrated circuit device. Therefore, a plurality of clock signals having different frequencies with aligned edges can be generated without the need for separately providing an external pin for inputting the reset signal or a circuit for generating the reset signal.

Abstract: Methods and structure for improving accuracy of a master delay line associated with slave delay lines wherein the master delay line is design utilizing a higher clock frequency then the clock frequency applied to associated slave delay lines. The higher clock frequency applied to the master delay line in accordance with the present invention permits the master delay line to be comprised of fewer delay elements than would be the case for a master delay line using the same basic clock frequency as associated slave delay lines. The lower number of delay elements comprising the master delay line (i.e., the shorter length of the master delay line) helps reduce static phase errors associated with the master delay line inherent in the design, layout and fabrication of a longer delay line.

Abstract: A novel clock control circuit and method in which phase synchronization with respect to an external clock can be realized without recourse to the external clocks. A clock controlling circuit includes a delay circuit sequence comprised of N stages of units each made up of a first delay circuit 10 and a first interior division circuit 11 for delaying the output signal of the first delay circuit, and a phase difference detection circuit 14 for detecting the clock period and the delay time difference of the delay circuit sequence from the input clock IN and a clock END output by the delay circuit sequence as a phase difference of the two signals. A plural number of second interior division circuits 12, fed with an output signal of the first delay circuit, delays a transition edge of an output signal of the first delay circuit by t2−n×T/N to output the delayed signal.

Abstract: A clock controller and clock generating method are provided for AC self-test timing analysis of a logic system. The controller includes latch circuitry which receives a DC input signal at a data input, and a pair of continuous out-of-phase clock signals at capture and launch clock inputs thereof. The latch circuitry outputs two overlapping pulses responsive to the DC input signal going high. The two overlapping pulses are provided to waveform shaper circuitry which produces therefrom two non-overlapping pulses at clock speed of the logic system to be tested. The two non-overlapping pulses are a single pair of clock pulses which facilitate AC self-test timing analysis of the logic system.

Abstract: A semiconductor integrated circuit device includes internal circuits divided into blocks that are controlled block by block for activation. Each internal circuit receives a clock signal from a clock distribution network of a block including that internal circuit. The clock signal is supplied to the clock distribution network by buses of a tree structure and a clock drive control gate. The clock drive control gate stops, in response to an enable signal for controlling activation of internal circuits block by block, the clock signal from being supplied, when internal circuits of a corresponding block are inactivated.

Abstract: Provided are a method and a system to distribute clock signals in digital circuits to ensure that the multiple clock signals reach multiple loads associated with the digital circuit, concurrently. To that end, an off-chip set of clock paths, which includes one or more clock buffers, are connected between two sets of clock paths on an integrated digital circuit. The multiple clock signals are routed to the off-chip set of clock paths to reduce, or remove, propagational delay in multiple clock signals that arise from the propagation of the same through the on-chip clock paths. This is achieved by the clock paths of the off-chip set of clock paths having differing resistivities, differing lengths or both.

Abstract: An apparatus comprising a first circuit and a second circuit. The first circuit may be configured to present a plurality of output clock signals and a first control signal in response to a reference clock signal and a feedback signal. The second circuit may be configured to select one of the plurality of output clock signals as the feedback signal in response to the first control signal.

Abstract: Disclosed is a clock signal control device which has: an oscillator which generates a clock signal; a pulse detecting circuit which detects the frequency or duty of the clock signal and outputs a control signal based on the result of detection; and a clock signal supply selecting circuit which generates a supply clock signal from the clock signal generated from the oscillator in response to the control signal from the pulse detecting circuit.

Abstract: In semiconductor integrated circuit devices containing a macro, a skew occurs between the clock pulse supplied to the latch in that mother circuit and the clock pulse supplied to the latch inside the macro. These clock skews obstruct the high frequency operation of the semiconductor integrated circuit device clock frequency so the semiconductor integrated circuit device cannot be operated at high speed.

Abstract: A clock distribution system and method for an integrated circuit includes a power supply line and a plurality of clock distribution elements. The power supply line is operable to provide resistive-capacitive (RC) filtered power. The clock distribution elements are coupled to the power supply line. The clock distribution elements are operable to be powered by the RC filtered power supply to distribute a reference clock signal.

Abstract: A method for computing a position for a zero-skew driver insertion point in an area occupied by nodes driven by the driver is described. The zero-skew driver insertion point is the position in the area where the spread of the signal arrival times at the nodes driven by the driver is minimized. The method includes: expressing a function describing a distance from each of the nodes to the zero-skew driver insertion point, expressing the variance of the function, minimizing the variance of the function, and solving an equation representative of the minimization of the variance of the function to determine the position of the zero-skew driver insertion point. In one embodiment, the minimizing the variance of the function includes: taking a first derivative of the function with respect to the distance, and setting the first derivative of the function to zero.

Abstract: A tree wiring distributes an externally supplied clock signal to a plurality of first clock buffers. Routes of the tree wiring are designed so that the externally supplied clock signal can reach the plurality of first clock buffer substantially at the same time. The plurality of first clock buffers are connected to all intersections existing on a mesh wiring in one to one correspondence. The plurality of first clock buffers supply a clock signal supplied thereto through the tree wiring, to the mesh wiring. The mesh wiring protrudes from the intersections thereof which face toward outside by a predetermined length in order to keep load imposed on the plurality of first clock buffers uniform. A plurality of second clock buffers are connected to the mesh wiring, and supply clock signals supplied thereto from the plurality of first clock buffers through the mesh wiring, to a plurality of circuit elements.

Abstract: A multi-phase clock generation circuit includes a clock generation circuit, first frequency divider circuit, first clock selection circuit, second to nth frequency divider circuits, second to nth clock selection circuits, and clock selection control section. The clock generation circuit generates 2n (n is a positive integer) reference clock signals having the same frequency and different phases. The frequency divider circuit frequency-divides one of the reference clock signals by 2 to generate clock signals 180° out of phase with each other. The first clock selection circuit selects one of each of the clock signals and a corresponding reference clock signal and outputs the selected signals as clock pulses. Each of the second to nth frequency divider circuits frequency-divides a clock pulse to generate clock signals 180° out of phase with each other.

Abstract: A semiconductor device includes a transmission line bounded by a first buffer and a second buffer. The first and second buffers are placed such that the transmission line has a length between a minimum and a maximum, thereby permitting narrow clock signal pulses to be transmitted with reduced distortion.

Abstract: In a semiconductor integrated circuit having a first circuit which outputs n (n is an integer of 2 or more) clock signals CKi (i is an integer of 1 to n) each of which is delayed by a delay time of i×T (T is a constant time) from a reference signal, and a second circuit which carries out signal processing using n clock signals input from the first circuit via n signal wirings, for at least a part of the n signal wirings, the positions of the edges of two clock signals transmitted on the two adjacent signal wirings are separated, as seen on the time base, by more than T in the time.

Abstract: An apparatus having a plurality of serially cascaded delay cells each configured to generate a phase of a multi-phase signal and an intermediate signal, where (i) each of the delay cells is generally configured to respond to a bias signal and one of the intermediate signals and (ii) a first of the delay cells is generally configured to respond to an input signal.

Abstract: A clock distribution system and method for an integrated circuit includes a power supply line and a plurality of clock distribution elements. The power supply line is operable to provide resistive-capacitive (RC) filtered power. The clock distribution elements are coupled to the power supply line. The clock distribution elements are operable to be powered by the RC filtered power supply to distribute a reference clock signal.

Abstract: In a clocking network with clock distribution in the gigahertz frequencies, low voltage swings are generated and applied instead of full voltage swings. The low voltage swing circuits are differential low voltage swing circuits. True and complement signals are transmitted in the global path, enabling cancellation of common mode noise picked up along the path from the generation point to the destination local ends, where the noise is subtracted from the signals. The low voltage swing circuits include a differential translator/driver, differential repeaters and differential receivers/translators to enable centrally generated low voltage swing clock signals to be distributed throughout the chip and to be faithfully converted to full voltage swing clock signals at the local ends.

Abstract: A system and method for generating and optimizing clock signals with non-overlapping edges on a chip using a unique programmable on-chip clock generator. Overlapping of the edges of the clocking signals is avoided by adjusting an amount of delay introduced in the on-chip clock generator circuit. The amount of delay is adjusted by programming the on-chip clock generator using either hardware and/or software programming. In hardware programming, the amount of delay adjusted by physically altering the composition of delay elements in the on-chip clock generator. In software programming, the delay is adjusted using software commands to control the operation of delay elements in the on-chip clock generator, or to select the paths that delay the signals.

Abstract: Provided are a method and a system to distribute clock signals in digital circuits to ensure that the multiple clock signals reach multiple loads associated with the digital circuit, concurrently. To that end, an off-chip set of clock paths, which includes one or more clock buffers, are connected between two sets of clock paths on an integrated digital circuit. The multiple clock signals are routed to the off-chip set of clock paths to reduce, or remove, propagational delay in multiple clock signals that arise from the propagation of the same through the on-chip clock paths. This is achieved by the clock paths of the off-chip set of clock paths having differing resistivities, differing lengths or both.

Abstract: A system and integrated circuit (die) including a clock generator that includes an on-chip inductor and uses the inherent capacitance of the load to generate a sinusoidal clock signal. The inductor is connected between a current source and an inverting switch. The output of the switch is a substantially sinusoidal signal that connected directly to at least a portion of the clock driven circuits without intermediate buffering. In the preferred embodiment, the clock generator is a dual phase design that includes a pair of cross-coupled MOSFET's, a pair of solid state on-chip inductors, and a current source. Each of the on-chip inductors is connected between the current source and the drain of one of the MOSFET's. The outputs of the clock generator are provided directly to the clock inputs of at least a portion of the clock driven circuits on the die.

Abstract: A clock system includes a provisioning layer corresponding to a plurality of input clocks, and a plurality of layers arranged according to a hierarchy. The first layer in the hierarchy is operable to arrange the input clocks into groups and for each group select a corresponding group output clock. The remaining layers in the hierarchy are operable to arrange the group output clocks from a next layer higher in the hierarchy into groups and for each group select a corresponding group output clock. The lowest layer in the hierarchy is operable to select one of the group output clocks from the next layer higher in the hierarchy as a selected clock.

Abstract: An integrated circuit having at least two clock systems in which the appropriate clock signal, starting from a clock input, can be forwarded through clock trees to individual switching elements or switching blocks. In this arrangement, each clock tree has an associated controlled switch which, for selected operating states, can be used to apply a single common clock signal to the clock trees, where at least a first clock tree has a PLL unit connected upstream of it, and an output of this clock tree is connected to an input of the PLL unit in order to form a phase locked loop, and the switches are actuated in selected operating states such that the common clock signal is supplied to a last clock tree, and an output of this clock tree is connected to the other input of the PLL unit for the at least first clock tree.

Abstract: A conditional clock buffer circuit includes a clock output and is coupled to receive a clock input and a condition signal. The conditional clock buffer circuit includes a first circuit coupled to receive the clock input and a second circuit coupled to receive the clock input and the condition signal. The first circuit is configured to generate a first state on the clock output responsive to a first phase of the clock input. The second circuit is configured to conditionally generate a second state on the clock output responsive to the condition signal during a first portion of a second phase of the clock input. In one implementation, one or more of the conditional clock buffer circuits may be included in a clock tree. The clock tree may also include one or more levels of buffering.

Abstract: A conditional clock buffer circuit includes a clock output and is coupled to receive a clock input and a condition signal. The conditional clock buffer circuit includes a first circuit coupled to receive the clock input and a second circuit coupled to receive the clock input and the condition signal. The first circuit is configured to generate a first state on the clock output responsive to a first phase of the clock input. The second circuit is configured to conditionally generate a second state on the clock output responsive to the condition signal during a first portion of a second phase of the clock input. In one implementation, one or more of the conditional clock buffer circuits may be included in a clock tree. The clock tree may also include one or more levels of buffering.

Abstract: An integrated circuit has a clock input for receiving a primary clock signal, clock reconfiguring device fed by the clock input for generating one or more secondary reconfigured clock signals, and utility circuitry fed by the clock reconfiguring device for constituting application utility functions under synchronization by the secondary clock signals. In particular, the clock input a clock upscaling device for from the primary clock signal generating an intermediate clock signal with an upscaled frequency for thereby feeding the clock reconfiguring device. Furthermore, the clock reconfiguring device a has late-programmable and low power memory driven by the intermediate clock signal for generating the secondary reconfigured clock signals. These are wave-shape patterns read-out from a plurality of separately and sequentially drivable memory locations.

Abstract: A semiconductor integrated circuit device for minimizing clock skew over clock wiring shortened for reduced wiring delays. A plurality of stages of clock drivers are provided on clock wiring paths ranging from a clock generator to flip-flops. Clock lines connecting upper stage clock drivers are equalized in length in the form of a tree structure, and clock lines connecting lower stage clock drivers are made as short as possible.

Abstract: To input buffers included in a peripheral pad group inputting an external signal and a DQ pad group for data input/output, clock signals from a synchronizing circuit are transmitted through a clock distributing circuit having a plurality of clock transmission nodes arranged in a shape of a tree. The synchronizing circuit accomplishes phase synchronization between a signal from a node nearest to the clock distributing circuit with an external clock signal. Thus, a skew in clock signals applied to the input and output buffers can be eliminated.

Abstract: A phase alignment technique includes providing a clock signal to a first clock distribution spine and providing at least one additional clock distribution spine. One PLL (Phase Locked Loop) is provided for each additional clock distribution spine, each PLL having an REF input and an FBK input and an output. The REF input of each PLL is connected to the first clock distribution spine and the FBK input of each PLL is connected to its respective clock distribution spine and the output of each PLL is connected to its respective clock distribution spine to provide a clock signal thereto. Each PLL provides phase alignment between the clock signal on the first clock distribution spine and the clock signal outputted by the PLL to its respective clock distribution spine. The first clock distribution spine and each additional clock distribution spine and its respective PLL may be disposed on an integrated circuit die.

Abstract: An electronic circuit has a clock input for receiving an input clock signal. A clock processing circuit derives derived clock signals from the input clock signal, for example by frequency dividing the input clock signal. A dual edge triggered sampling circuit samples the derived clock signals at both rising and falling edges of the input clock signal. The sampled clocks are thus synchronized and are used to control operation of processing circuitry.

Abstract: An apparatus comprising a first circuit and a second circuit. The first circuit may be configured to present a plurality of output clock signals in response to a reference clock signal and a feedback signal. The second circuit may be configured to select one of the plurality of output clock signals as the feedback signal in response to a first control signal. The first control signal may be configured to minimize a difference in delay between the plurality of output clock signals.

Abstract: The interleaved clock generator generates N interleaved clock signals in response to an input clock signal. The interleaved clock generator comprises an interleaved clock generator of a first type for receiving the input clock signal and for generating M interleaved intermediate clock signals in response to the input clock signal. The interleaved clock generator of the first type includes either a multi-stage serial-delay circuit or a ring counter circuit. The interleaved clock generator additionally comprises M interleaved clock generators of a second type, each of which is each for receiving a respective one of the intermediate clock signals from the clock generator of the first type and for generating N/M of the N interleaved clock signals in response to the respective one of the intermediate clock signals.