Abstract: A complementary waveform driver is disclosed that generates output signals SOUT with arbitrary high and low drive states with respect to an independently controlled baseline signal SBL. Accordingly, the driver can generate very fast and flexible waveforms with multiple levels and baseline components. The driver implements complementary differential pairs of transistors that alternately source and sink programmable currents to an output port, creating an output waveform with excellent rising and falling edge symmetry, and greatly improved fidelity, especially at low level voltage swings. A complementary amplifier stage defines the baseline voltage level. When combined with a programmable active load and window comparator, the driver is particularly suited for pin electronics in automatic test equipment (ATE) applications.

Abstract: A pulse generating apparatus efficiently generates a pulse signal by receiving a control signal. A voltage level controller 20 receives a control signal and outputs a certain voltage through a node N0. A output level variation element C is placed between a node N0 and a node N1. A switching element 30 applies a high voltage Vcc to the node N1. A switching element 40 applies a low voltage Vss to the node N1. The pulse is generated by a logic operation of the control signal and a voltage on a node N0.

Abstract: A duty ratio can be corrected to 1:1 without affecting the operation of a PLL or DLL circuit. A rising-edge control circuit (1a) generates a signal (S10) by inverting a signal (S6), and varies a time required for a high to low transition of the signal (S10). A comparator (A1) causes a transition of a signal (S2) when the signal (S10) becomes less than a reference value (Vref), so the duty ratio of the signal (S2) varies according to the length of its fall time. A duty-ratio detecting circuit (2) is a charge pump for drawing or passing a constant amount of current according to a voltage of the signal (S2). A duty-ratio correction filter (3) converts a signal (S8) obtained from the duty-ratio detecting circuit (2) into a smooth voltage signal (S9). This signal (S9) becomes a feedback signal to the rising-edge control circuit (1a) for correcting the duty ratio of the signal (S2) to 1:1.

Abstract: A system and method for preventing time-walking in a digital switching network when switching from a first clock to a second clock. The first and second clock can be identical in frequency and independent in phase, where the highest resolution frequency available is that of said first and second clock. The system can include a clock divider selection circuit, an enhanced digital phase aligner, and a clock select control circuit. The clock divider selection circuit can output an on-line divided clock and an off-line clock to the enhanced digital phase aligner. The enhanced digital phase aligner can sample the on-line divided clock with four phases of the off-line clock and output an off-line divided clock which is time shifted such that the off-line divided clock is in phase with the on-line divided clock within plus or minus one-half the clock period of the off-line clock.

Abstract: A clock switch controller has a clock status register which stores current clock data which identifies which of two or more clock signal sources is a current clock signal source currently in use as a system clock signal source. State machine logic of the controller automatically switches, in response to a clock switch signal, the system clock signal source from the current clock signal source to a new clock signal source of the two or more clock signal sources.

Abstract: A semiconductor integrated circuit is provided which has an internal core area in which a first set of transistors are regularly arranged, and a peripheral area in which a second set of transistors are arranged to constitute input/output circuits. In this semiconductor integrated circuit, the transistors arranged in the peripheral area include a plurality of transistors that are not used to constitute the input/output circuits, and these unused transistors constitute at least one driver for driving at least one of circuits constituted by the transistors arranged in the internal core area.

Abstract: A programmable multi-scheme clocking circuit supports multiple applications. In one implementation, the clocking circuit includes multiple clock sources such as a crystal oscillator, a RC oscillator, an internal oscillator, and an external clock. Each of the clock sources can be enabled by a respective control signal. A multiplexer couples to the clock sources and provides a clock signal from one of the clock sources as the output clock signal. External support circuitry (e.g., external tank circuits) for some of the clock sources (e.g., the crystal oscillator and the RC oscillator) can be coupled to the clocking circuit through one or more device pins. The pins to support the crystal oscillator, the RC oscillator, and the external clock signal are shared so that no additional device pins are required.

Abstract: A master and slave arrangement of processors includes a clock signal synchronization apparatus. The clock signals of two (processor) assemblies in micro-synchronous operation are only allowed to exhibit an extremely slight phase difference. A system clock signal is generated by a voltage controlled oscillator, which is fed by phase detectors with a filter at the output of each phase detector. Switches are provided between the filter output and the voltage controlled oscillator input. The phase detectors compare the system clock signal and a reference clock signal. A delay is provided at the input of one phase detector.

Abstract: In order to prevent the value of a flipflop from being indefinite during a period from a power-on time to the time a first clock signal is inputted, a reset circuit for a flipflop is configured to supply a clock to a clock input terminal of each of flipflops at the power-on time, so that an output of each flipflop never becomes indefinite. For example, in the case that an input/output of tristate buffers coinected in common to the same bus are controlled by a corresponding number of flipflops, respectively, a pass-through current caused for an output collision on the bus can be prevented with a relatively small scale of circuit.

Abstract: A clock provider system (100) receives an input clock X1 and, shifted by 90.degree., an input clock X2 and provides output clock Y as a free selectable logical function Y=f(X1, X2). A signal provider (103) comprises non-inverting delay units (150) and inverting delay units (160) each forwarding the input clocks X1 and X2 with a substantially equal delay. According to the required logical function, a distributor unit (170) sends the delayed signals to control inputs of a switch matrix (100) for providing intermediate signal Z. At the output, an inverter (102) inverts Z and provides Y. In the switch matrix (100), transistor chains (115, 116, 125, 126) alternatively pull an intermediate node (130, signal Z) either to a first (191) or to a second (192) reference potential. Thereby, near reference transistors (111, 114, 121, 124) are made conductive prior to near node transistors (112, 113, 122, 123).

Abstract: A slave clock generation system and method suitable for use with synchronous telecommunications networks generates one or more slave clocks from a selected reference clock using a direct digital synthesis technique. A multiplexer selects a reference clock from a number of available sources, each of which can be at its own spot frequency, based on a predetermined selection order. Toggle detectors monitor each of the available clock sources, and block the selection of any that are not within a specified frequency range. A local oscillator establishes short-term and long-term measurement periods; the cycles of the selected reference clock are counted over consecutive short-term measurement periods to determine the relative frequency of the selected clock with respect to the frequency of the local oscillator. The cycle counts are fed to a phase-to-clock converter, which produces a slave clock output having a frequency that varies with the relative frequency measured for the selected clock.

Abstract: A timing signal generation circuit according to the present invention includes: a delay circuit for transmitting an input clock signal while delaying the clock signal, the delay circuit having a plurality of intermediate taps capable of outputting the clock signal at their corresponding positions in the delay circuit; a detection delay circuit for transmitting the clock signal while delaying the clock signal, the detection delay circuit having a plurality of intermediate taps capable of outputting the clock signal at their corresponding positions in the detection delay circuit; a plurality of sample/hold circuits each having a sampling signal terminal, the sampling signal terminals being connected to corresponding ones of the plurality of intermediate taps of the detection delay circuit; a plurality of boundary delay circuits for detecting an edge of the clock signal, the boundary detection circuits being connected to respective output terminals of the sample/hold circuits; and an output selection circuit for

Abstract: A clock switching system for providing synchronous glitch-free switching of a clock source from among one or more asynchronous clock sources comprises a multiplexor device for providing a system clock output signal corresponding to a first asynchronous clock source input, and a switch control circuit for generating first and second control signal. In response to the first control signal, the multiplexor device enables simultaneous coupling of a selected second asynchronous clock source to be switched to the multiplexor circuit, and decoupling the first asynchronous clock source input. Further in response to the first control signal, the system clock output is held at a first output level. In response to the second control signal, the second asynchronous clock source is coupled to the system clock output while both signals are at the first output level.

Abstract: A semiconductor device for generating first and second internal clocks complementary with each other from an external clock and usable for both a system of a type using a complementary clock and a system of a type generating a 180.degree. phase clock internally, is disclosed. A first clock input circuit (buffer) is supplied with a first external clock and outputs a first internal clock. A second clock input circuit (buffer) is supplied with a second external clock complementary with the first external clock and outputs a second clock. A 1/2 phase clock generating circuit generates a 1/2 phase shift signal 180.degree. out of phase with the first internal clock. A second external clock state detection circuit judges whether the second external clock is input to the second clock input buffer.

Abstract: A 2/N mode clock generator that generates bus clock signals through the use of bus clock enable signals selecting bus clock pulses that are in phase and out of phase with a core clock signal. The clock generator maintains synchronization between the bus clock signal and the core clock signal so that they are always in a predetermined phase relationship.

Abstract: A clock control circuit receives an external clock signal and generates an internal clock signal. Through use of internal programming and an external trigger signal, the clock control circuit blocks out one or more of the clock cycles of the external clock signal to generate the internal clock signal. The clock control circuit can be used in any semiconductor device, and especially in synchronous flash memory devices with a burst operation. In the synchronous flash memory devices, one or more of the internal clock cycles are blocked out to account for increased delays during certain data sensing operations such as word line switching during data reading. In the synchronous flash memory devices, the sensed data is stored in input/output buffers and transferred out synchronously to the external clock signal.

Abstract: In order to use a digital oscillator to generate a target frequency ZT with a "high" or "low" level constant in time from a working clock by variable division by a first division factor, two divider circuits which can be respectively triggered by the positive or the negative edges of a working clock, and to which a control word can be directed alternately by means of a first controlled switch, and which are connected on their output sides to a second controlled switch to obtain a clock pulse. To that end each divider circuit has a logic module which detects the occurrence of the edge of the control word and stores this event, with this event triggering a division by a second division factor.

Abstract: A data processing apparatus functions as a timer or counter by counting clock pulses of a system clock signal to generate a timing signal. The system clock signal is generated as one of either a first or a second basic clock signal generated by two respective oscillators. Even if the second basic clock signal which has a lower frequency fluctuates, the data processing apparatus can accurately generate a pulse signal having a desired period. When the first basic clock signal is selected as the system clock signal, the second basic clock signal is measured with the system clock signal. When the second basic clock signal is selected as the system clock signal, a numerical value up to which the clock pulses of the system clock signal are counted is corrected on the basis of the measured second basic clock signal.

Abstract: A clock generating system used to generate a clock signal which compensates for chip operating conditions. The system includes a delay line oscillator and a reference clock which determines the actual propagation time of delay elements on the chip. A clock generator which includes a number of serially connected delay units uses this information to generate a clock signal for the chip logic functions. The output clock rums the chip logic functions at the proper frequency for the current chip conditions.

Abstract: A circuit for the glitch-free changeover between digital signals includes a multiplexer having a multiplicity of signal input terminals, signal select terminals and a signal output terminal. Furthermore, the circuit includes a counter logic unit for counting pulses in the output signal of the multiplexer and for outputting a count signal when a specific count value is reached. A delay logic unit delays a multiplexer select signal and outputs a switching signal and a delayed multiplexer select signal. During a set switching signal the counter logic unit is activated and the circuit output is deactivated.

Abstract: In integrated circuits, to modify the operation of the charge pumps or voltage step-up circuits, they are sent a variable frequency signal at the input with the aim of breaking the regularity of the pulse train that enters the charge pump. This limits the risks of entry into resonance and limits radiation at a given frequency. The variable frequency signal is typically produced by a logic circuit and by a main oscillator whose transmission of certain pulses is masked by the combined action of different masking signals. The duty cycle ratios of the masking signals are less than that of the signal from the main oscillator. Such duty cycle ratios are preferably produced following the passage of a signal to a lower frequency than that of the signal of the main oscillator in a circuit for the detection of high transitions.

Abstract: A variable clock generator includes a clock multiplier that generates from a reference clock at least two clock signals which are out of phase with each other and a clock divider which receives a plurality of divider patterns and which receives at least two clock signals from the clock multiplier. The clock divider generates an output clock based on the divider patterns and the clock signals. In a particular embodiment, the clock divider includes a plurality of loadable linear feedback shift registers each having an output. An EXCLUSIVE OR gate that is responsive to the outputs of the linear feedback shift registers then EXCLUSIVE ORs the outputs of the linear feedback shift registers to produce the output clock. Preferably, the size of the linear feedback shift registers corresponds to the size of the divider patterns.

Abstract: A method and apparatus for clocking an integrated circuit. The apparatus includes an integrated circuit having a clock driver disposed in a first side of a semiconductor substrate, and a clock distribution network coupled to the clock driver and disposed in a second side of the semiconductor substrate to send a clock signal to clock an area of the integrated circuit.

Abstract: A digital pulse generator having a high-speed clock (22) and two clock pulse counters (10 and 12), one (10) to time the start of each pulse and one (12) to time the pulsewidth, based on clock counts supplied from a microcontroller (14) to which a user inputs desired pulse parameters. The combination of the high-speed clock (22) and the clock pulse counters (10 and 12) produces precise and reliable output pulses for a variety of applications, and at a relatively low cost. Operation may be selected to be in internal mode, in which successive pulses are produced at a desired period, or an external mode, in which a pulse is generated after a selected time delay. A trigger signal input circuit (48, 32) and a trigger signal output circuit (42), both with adjustable impedances, facilitate interconnection of multiple digital pulse generators as needed for a given application.

Abstract: It is to achieve a logic signal selection circuit having high timing resolution and high speed.

Abstract: A power management system is disclosed. The system includes an oscillator interface for use in a power management system, a power recycle circuit for use in a power management system, a pad clock and self test for use in a power management system, a clock enable circuit for use in a power management system, a power level detect circuit for use in a power management system, an internal source clock generation circuit for use in a power management system, and a power-save mode change detection circuit for use in a power management system. The oscillator interface includes an interface circuit for interfacing with an external oscillator used as a source of oscillations. A clock stabilization filter masks out spurious crystal frequencies in the oscillations during start-up of the power management system following an enabling of a feedback loop. The clock stabilization filter has circuitry which provides that the oscillations will start with a rising transition after filtering.

Abstract: A clock forwarding circuit of a semiconductor integrated circuit which increases an operation timing margin of a data receive port and reduces power consumption, and a clock forwarding method, are provided. In the clock forwarding circuit for performing the clock forwarding method, upon abnormal operation of the semiconductor integrated circuit, such as during power-up or initialization, the data receive port captures the amount of interconnection delay of a data line and generates a receive clock signal which is self-generated, from a delayed send clock transmitted from a data send port via the data line. On the other hand, when the circuit operates in a normal operation mode, the data receive port receives data transmitted from the data send port via the data line, in response to the self-generated receive clock. Accordingly, the amount of interconnection delay of the data line is previously captured and data is received in response to the self-generated receive clock.

Abstract: The entire data path of a synchronous integrated circuit device is initialized in a test mode upon power-up of the synchronous integrated circuit device. Upon power-up of the integrated circuit device in the test mode, a clock signal (either an external clock signal or an associated internal clock signal) is internally clocked. As the clock signal goes to a low logic state upon power-up of the device, a master latch (flip-flop) element of the integrated circuit device is loaded with data and is allowed to conduct; a slave latch (flip-flop) element of the integrated circuit device does not conduct. As the clock signal goes to a high logic state, the data in the master latch is latched. Also upon the high logic state of the clock, the slave latch element is loaded with data and is allowed to conduct.

Abstract: Oscillating circuitry built in integrated circuitry (1) comprises a ring oscillator (31) for generating a first clock, an external oscillator (40) capable of generating a second clock in either one of two oscillating modes which is determined according to an external circuit (12 and 13, or 6 through 8) connected to terminals (2 and 3) thereof, and an internal clock selection circuit (41) which delivers the first clock as an internal clock to the integrated circuitry (1) just after the integrated circuitry (1) is activated or reset, stops the delivery of the first clock and simultaneously furnishes a signal held at a logic high level as the internal clock in response to a control signal for instructing a selection of the second clock, and then determines whether or not the external oscillator (40) is generating the second clock properly, and which furnishes the second clock as the internal clock when it determines that the external oscillator (40) is generating the second clock properly.

Abstract: A processing system includes circuitry and methodology for selecting clock generation modes between phase-locked loop and static delay line loop circuitries. The node may be selectable through an externally accessible pin, an internal bond wire option, a boundary test scan control point, or other programmable register or control point.

Abstract: After a level of a selection signal C is changed, a currently output clock signal present at an output line is interrupted (set to be a low level) at the fall of the level of the currently output clock signal (A or B), and a switching operation is started. After the switching, the supply of an extracted clock signal to the output line is resumed when the level of the extracted clock signal (A or B) is changed. The best clock signal, which is synchronized with a plurality of source clock signals, can be provided to another system such as an IC card without increasing the number of parts. No noise is generated at a clock signal switching time, and the time required for switching can be kept to a minimum.

Abstract: A phased lock loop (PLL) clock circuit generates a clock signal at 1x the desired clock frequency while maintaining substantially a 50% duty cycle. A first loop provides a feedback signal to maintain clock frequency, while a second loop provides a feedback signal and controls duty cycle. Two clock signals from a ring oscillator are fed to a level shifter, where each clock signal triggers a respective rising or trailing edge of the output clock signal. The level shifter is provided with a delay for controlling timing of the trailing edge of the output clock signal. The output clock signal is fed to a equi-current buffer where a charge pump, driven by the output clock signal, charges and discharges a capacitor in proportion to the duty cycle of the output clock signal, producing a feedback control voltage. The feedback control voltage is applied to the delay of the level shifter to maintain a substantially 50% duty cycle.

Abstract: A multi-clock pulse synchronizer circuit with and IN-section receiving and storing prescribed in-pulses and input clock signals and responsively outputting intermediate pulses; and an OUT-section for receiving and storing the intermediate pulses, synchronous with certain output clock signals and processing them to generate certain output-signals, for better avoiding metastability.

Abstract: A method and a completely integrable circuit arrangement are proposed for recovery of a timing signal from a data stream. Two groups of phase regulators are supplied with a locally existing reference timing signal, preferably in each case one of mutually complementary reference timing signals. One phase regulator in each case, which has assumed a state within its operating range, is selected to provide the recovered timing signal, while a phase regulator which is currently not selected is kept in the state within its operating range which is diametrically opposite to the state of the currently selected phase regulator. On reaching the limit of the operating range of the currently selected phase regulator, a changeover is made to the phase regulator which has been kept ready until this point.

Abstract: It is to realize a function clock generation circuit with which a wiring area and cell area, and further a power consumption can be reduced, and a timing design is easy. An input terminal D of a through latch circuit LTC11 is connected to an input line of an enable signal EN, an inversion clock input terminal G is connected to the input line of the clock signal, one input terminal of a NAND gate NAND11 is connected to an output terminal Q of a through latch circuit LTC11, the other input terminal is connected to the input terminal of the clock signal CK, and the output terminal is connected to the input terminal of an inverter INV11. Then, in the through latch circuit LTC11, the enable signal EN is sampled at the rising edge of the clock signal CK, and according to the value, the clock pulse immediately after the sampling is passed or blocked by the logical gate LGT comprising a NAND gate NAND11 and an inverter INV11.

Abstract: An apparatus for multiplexing a pair of test clock signals and a pair of system clock signals onto a pair of output clock signals includes a first means for coupling a first test clock signal to a first output clock signal when a test mode control signal is active, for driving the first output clock signal to an inactive clock signal level when the test mode control signal transitions to an inactive state, and for coupling a first system clock signal to the first output clock signal beginning with a first full clock pulse of the first system clock signal which occurs after the test mode control signal transitions to the inactive state.

Abstract: A deviation of a clock rate of the timepiece clock signal is determined relative to a reference clock rate of a reference clock signal (CR) which is either issued while the mobile unit is switched on or is contained in a received signal. The reference clock rate is higher than the clock rate of the timepiece clock signal. A count number (N) is calculated based on the deviation of the clock rate of the timepiece clock signal. The clock signal is generated such that the clock pulses the clock signal are successively issued each time the clock pulses of the timepiece clock signal counted up to the count number.

Abstract: Generator of clock pulses having a period selectable between a first period, a second period of greater duration than that of the first period and a third period, with duration imposed by the transitions of a synchronization signal (SYNC) from a first to a second logic level, comprising: a resettable oscillator controlled by a binary selection signal having a first and second logic level, in order to generate periodic pulses having the first or second period depending on the logic level of the said selection signal, the oscillator comprising a pulse extractor triggered by the periodic pulses and by the transitions from first to second logic level of the synchronization signal in order to generate, with each pulse and transition received as input, one of the said periodic clock pulses, acting as reset signal for the oscillator, and a finite state logic machine, having at least two states A, B and inputs for receiving the synchronization signal and the periodic pulses, and generating the selection signal at a f

Abstract: A 2/N mode clock generator that generates bus clock signals through the use of bus clock enable signals selecting bus clock pulses that are in phase and out of phase with a core clock signal. The clock generator maintains synchronization between the bus clock signal and the core clock signal so that they are always in a predetermined phase relationship.

Abstract: The present invention provides a clocking circuit allowing individual macrocells in a particular macrocell block of a CPLD to use different polarities of the same clock. The input clock pin can now drive all the macrocells directly, which can eliminate additional buffering states and improve the clock to out timing, Tco, by (for example) 300 ps. The clocks are presented directly to the clock selection multiplexers for each macrocell. Additional functioning may be realized by implementing additional configuration bits inside the clocking architecture.

Abstract: A circuit and method for switching between different frequency clock domains that are out of phase. The circuit has a select input for selecting which frequency domain is to be output, a first circuit associated with the first clock domain, and a second circuit associated with the second clock domain. The first and second circuits are responsive to the select input and work together to disengage the first clock before the second clock is engaged.

Abstract: A totem pole driver with cross conductive protection and default low impedance state output employs a totem pole output formed by top and bottom output transistors. A first circuit path switches the bottom output transistor on or off in response to a switching signal. A second circuit path, slower than the first circuit path, switches the top output transistor on in response to the switching signal after the bottom output transistor is switched off. A third circuit path switches the top output transistor off in response to a sync signal known to lead the switching signal. An emergency voltage supply is made available to hold the bottom output transistor on and the top output transistor off if the regulated circuit voltage is lost.

Abstract: A timer which provides both the surveying and counting functions. It contains a counter, a multiplexer, an edge-triggered controller, a time-base latching circuit, and a pulse-detecting circuit. It not only can be used as a timer, but can also be used as a counter to count the number of the external signals so as to detect the width of an external signal.

Abstract: A clock signal providing circuit with enable and pulse generator with enable for use in a block clock circuit of a programmable logic device (PLD), the block clock circuit for allocating multiple clock signals to each macrocell of the PLD. The clock signal providing circuit includes circuitry which functions to change states in response to a pin clock signal when an enable signal is active, and to maintain its current state when the enable signal is inactive. The pulse generator includes circuitry which functions to provide a pulse at a first edge of a pin clock signal if an enable signal remains active from prior to receipt of the first edge of the pin clock signal.

Abstract: Systems allowing smooth, trouble-free, "transparent" switchover from a "Primary clock" to a "Secondary clock", with no loss of clock or essential pulse-width, and where the "Secondary clock" may be completely separate from, and independent of, the "Primary clock.

Abstract: In a semiconductor integrated circuit having an internal wiring conductor for transferring an internal signal, an intermediate voltage generator generates an intermediate voltage equal to a half of a power supply voltage, and a driver circuit receives the intermediate voltage and the internal signal, for generating to the internal wiring conductor a positive/negative pulse signal having the intermediate voltage as a reference level, in response to a rising/falling edge of the internal signal. A receiver circuit receives the positive/negative pulse signal transferred through the internal wiring conductor. An output of the receiver circuit is set in response to a positive pulse of the positive/negative pulse signal, and reset in response to a negative pulse of the positive/negative pulse signal.

Abstract: In a clock signal control circuit of a semiconductor device, a first clock signal is externally supplied to a first terminal of the semiconductor device in an external clock signal mode. In an external element using mode, a second clock signal is generated on said first terminal by a clocked inverter and a self-biasing resistor composed of a P-channel MOS transistor and N-channel MOS transistor, using elements externally connected between the first terminal and a second terminal of the semiconductor device. The clock signal on said second terminal in the external clock signal mode or the external element using mode is supplied to the internal circuit of the semiconductor device using a Schnmitt trigger type of logic gate. In the external clock signal mode, the clocked inverter and the self-biasing resistor are turned off such that the generation of the second clock signal is inhibited. Further, in a clock signal stop mode, the supply of the clock signal is inhibited.

Abstract: A circuit for detecting timing errors and for selecting the correct clock edge for mid-point data sampling, includes a rising edge sampling device for sampling an input data signal at a rising edge of an input clock and generating a first interim data signal. A falling edge sampling device samples the input data signal at a falling edge of the input clock and generates a second interim data signal. An error signal generation devise, arranged in each of the rising edge and falling edge sampling devices, generates an error signal if designated setup time and hold time requirements are not met. The error signal is one of an error-rise or error-fall signal. A state machine receives the first and second interim signals and the error signal. The state machine automatically outputs the first interim data signal to a logic device if the error-fall signal is detected, and outputs the second interim data signal to the logic device if the error-rise signal is detected.

Abstract: A first signal .phi.1 is produced from an external clock CLK. A second ond signal .phi.2 is produced from a clock enabling signal CKE for controlling an internal clock of a SDRAM. A phase compensated signal .phi.3 is produced by advancing the phase angle of the signal .phi.1. A control signal .phi.4 is produced by a D-type flipflop from the signals .phi.1 and .phi.2. A phase-advanced internal clock .phi.6 is produced from the signals .phi.3 and .phi.4 through an RS-type flipflop and an OR gate. The phase-advanced internal clock .phi.6 thus has no error producing waveform.

Abstract: A state machine is configured with a phase-locked loop clock signal generator which can operate at a rate faster than an externally generated reference clock signal applied to the phase-locked loop. The output of the phase-locked loop is used to trigger registers coupled to the state machine at a selected rate to enable signals at output terminals of the state machine to be updated at a rate different than the rate of the externally generated reference clock signal.