Abstract: A flip-flop circuit includes a master latch and a slave latch, where a latch operation of the slave latch is controlled by a comparison result between an output signal of the master latch and an output signal of the slave latch. For example, a master latch gate receives an input signal and outputs the input signal under control of a clock signal and an inverted clock signal. A master latch receives the signal output by the master latch gate and latches the signal output by the master latch gate under control of the clock signal and the inverted clock signal. A slave latch gate receives the signal latched by the master latch and outputs the signal latched by the master latch under control of the clock signal and the inverted clock signal. A slave latch receives the signal output by the slave latch gate and latches the signal output by the slave latch gate under control of a slave latch control signal and an inverted slave latch control signal.

Abstract: A teacher-pupil flip-flop with reduced register delay including a gate circuit, a stack circuit, a keeper circuit, a teacher output circuit, a latch circuit and a pupil output circuit. The gate circuit switches after a setup delay in response to transitions of a clock signal. The stack circuit, coupled to the gate circuit output and to an input, switches an intermediate node pair to a preliminary state when the clock signal is low, and to a data state indicative of the input after the setup delay when the clock signal goes high. The keeper circuit maintains the data state and the teacher output circuit drives the output based on the data state while the clock is high. The latch circuit stores the data state and the pupil output circuit drives the output with valid data from the latch circuit after the clock signal goes low.

Abstract: A scan flip-flop (100A) that may operate as a positive flip-flop or a negative flip-flop in a normal operating mode has been disclosed. Scan flip-flop (100A) may include a master latching circuit (11), a slave latching circuit (12), and a clock circuit (13A). Clock circuit (13A) may receive a signal (XA), a control signal (control), and a mode signal (SCN). Signal (XA) may select between a positive flip-flop operation and a negative flip-flop operation when in a normal operating mode. Mode signal (SCN) may select between a normal operating mode and a scan test mode. Control signal (control) may disable signal (XA) so that scan flip-flop (100A) may operate in a known mode, such as a positive flip-flop, regardless as to the value of signal (XA). Scan flip-flop (100A) may reduce logic gates in clock lines which may be required in a conventional approach.

Abstract: A method and apparatus for disabling the scan output of flip-flops contained within an integrated circuit. Registers within the integrated circuit form a serial shift register chain when in the test mode of operation. The registers contain therein flip-flops, each of the flip-flops having at least one data input, a scan test input, a data output, and a scan output. The flip-flop is capable of storing either the signal appearing on the at least one data input or the signal appearing on the scan test input, based on the mode of operation of the flip-flop. The flip-flop includes a circuit coupled between the data output and the scan output for selectively disabling the scan output from following the value of the data output. Consequently, the scan output is enabled to output the logic value stored in the flip-flop when the flip-flop is in the test mode of operation and is disabled from outputting the logic value stored in the flip-flop when the flip-flop is in the normal mode of operation.

Abstract: A flip-flop circuit (100) that may have a reduced delay time between an edge of a clock input signal and a data output signal has been disclosed. A data signal may be received at a data input terminal (1), a clock input signal may be received at a clock signal input terminal (2), and data may be provided at a data output terminal (3). Data may be transferred from a master latch to a slave latch through a transfer circuit in response to an edge of a clock input signal. A transfer circuit may include a transfer device (6) which may have a control terminal connected to a clock signal input terminal (2) and a transfer device (5) which may have a control terminal connected to a buffered clock signal (C). In this way, delay time may be reduced while maintaining high-speed operations even if an input clock signal has a rounded or distorted waveform.

Abstract: A data latch circuit of the present invention, which corresponds to the semiconductor circuit, is provided with a master flip-flop and a slave flip-flop. The master flip-flop fetches a first signal in response to a first clock signal, holds first data corresponding to the first signal as binary data in response to the first clock signal, and also outputs the first data as a second signal. The slave flip-flop fetches the second signal in response to an OR-gated result obtained between the first clock signal and either one or a plurality of second clock signals, and the slave flip-flop holds second data corresponding to the second signal in response to the OR-gated result, and also the slave flip-flop outputs a third signal corresponding to the second data.

Abstract: An apparatus comprising a first circuit and a second circuit. The first circuit may be configured to generate one or more first control signals in response to a reference impedance. The second circuit may be configured to operate in (i) a first mode in response to a first state of a second control signal and (ii) a second mode in response to a second state of the second control signal. When the second circuit is in the first mode, an output impedance of the second circuit may be adjusted in response to the one or more first control signals and the one or more first control signals may be presented at a first input/output of the second circuit. When the second circuit is in the second mode, the output impedance of the second circuit may be adjusted in response to one or more third control signals received at a second input/output of the second circuit.

Abstract: A storage element (16) is formed to have a reset signal (R,RB) that overrides the operation of a clock signal (C,CB). The storage element has two voltage swings used for two different internal logic levels. The storage element (16) is also formed to ensure that the two voltage levels do not saturate the transistors within the storage element (16).

Abstract: The semiconductor integrated circuit includes a first transistor which flows a current from a high voltage source to a first node, a second transistor which flows a current from the first node to a low voltage source. Furthermore, a first inverter receives an input signal and drives the first node based on this input signal, and a second inverter drives a second node based on a voltage of the first node.

Abstract: Flip-flop circuitry having an input configured to receive an input signal and an output configured to deliver an output signal corresponding to the input signal; a clock terminal configured to provide timing signals for reception of the input signal at the input and transmission of the output signal at the output; two on-path inverters connected serially between the input and output, and configured not to respond to the timing signals; and two feedback inverters respectively connected in parallel with the two on-path inverters, the first and second feedback inverters being configured to respond to the timing signals.

Abstract: A device and method for improving the synchronization and metastability resolving capabilities of a flip flop. At least one master latch resolves a metastable condition of a received data signal thereby generating a stable data signal which is received and then displayed by a slave latch. Latches with superior metastability time resolution are configured in a master-slave relationship along with a novel clocking scheme whereby the clock signal supplied to the master latch is inverted as compared to that which is supplied to slave latch. As a result, the input data is latched on a falling edge of a clock signal and subsequently displayed on the rising edge of the clock signal providing at one half cycle for the input data to settle before passing out the data thereby allowing metastabilities to resolve during that period.

Abstract: A semiconductor integrated circuit including: a first latch to pass or store a signal in accordance with a logic value of a first internal clock signal; a second latch connected in series to the first latch, to pass or store a signal in accordance with a logic value of a second internal clock signal, with inverted operational characteristics in regard to the first latch; comparators to compare signal logic values at signal-input and -output nodes of the first latch; and the second latch; a first clock controller to generate a signal having a specific logic value in dependence on whether nodes of the first latch have the same or different signal logic values, as the first internal clock signal, based on the output of the first comparator; and a second clock controller to generate a signal having a specific logic value in dependence on whether nodes of the second latch have different signal logic values, as the second internal clock signal, based on the output of the second comparator.

Abstract: An error-correcting partial latch stage includes a first pass gate having an input for receiving a data input signal, an output, and a control node for receiving a control signal, a second pass gate having an input coupled to the output of the first pass gate, an output for providing a data output signal, and a control node for receiving the control signal, an inverter having an input coupled to the output of the first pass gate and an output; and a correcting inverter stage having a first input coupled to the output of the inverter, and second and third inputs for receiving voting signals from adjacent error-correcting latch stages, and an output coupled to the output of the second pass gate. A full latch stage includes three interconnected partial latch stages. The full latch stage has a high degree of immunity from SEU events and from on-chip noise coupling.

Abstract: A flip-flop circuit comprising: a master latch circuit; a slave latch circuit coupled to the master latch circuit; and a correction circuit for increasing an amount of charge that can be absorbed by the master latch circuit in response to a soft-error event when the slave latch circuit is in a transparent phase and when both the master and slave latch circuits are storing the same data.

Abstract: An apparatus comprising a first circuit, a second circuit and a third circuit. The first circuit may be configured to receive a first input signal and a second input signal and present a first signal and a second signal. The second circuit may be configured to present a first output signal in response to the first input signal, the first signal and the second signal. The third circuit may be configured to present a second output signal in response to the second input signal, the first signal and the second signal.

Abstract: A scannable asynchronous preset and/or clear flip-flop having latch circuits 27 and 30. Latch circuit 27 comprises an inverter 28 and a tristate NAND gate 29. Latch circuit 30 comprises an inverter 31 and a tristate NOR gate 32. When the CLK (clock input signal) and CLRZ (the inverse of the clear input signal) are both low, the output of the tristate NOR gate 32 is forced low. Thus the input of inverter 31 is low so that the output signal, Q, is forced low and the inverse output signal, QZ, is forced high. When CLK is high and CLRZ is low the output of tristate NAND gate 29 is forced high so that the input to inverter 28 is high and the input to inverter 31 is low, thereby forcing Q low and QZ high. Thus the outputs Q and QZ are forced low and high respectively when CLRZ is low, regardless of the state of the CLK input.

Abstract: A novel 2/3 full-speed divider operating at high speed with low power consumption comprising a ECL D flip-flop in master-slave configuration and a phases-selection block is provided in the present invention. The master latch and slave latch comprise a pair of input terminals, a pair of control terminals, and a pair of output terminals. The master latch further comprises two pairs of complementary cross-couple transistors for amplifying the output of the master latch for entering the phase-selection block. The phase-selection block has a pair of input terminals, a clock signal input terminal, and an output terminal generating an output signal adjusted by a division ratio according to the clock signal. The division ratio is either 1/2 or 1/3 and the divider functions as a 2/3 divider.

Abstract: A differential D flip-flop is disclosed including respective master and slave cells. The master cell comprises a first data set circuit and a first data store circuit. The data set circuit has a first differential input and a first differential output. The first data store circuit couples to the output of the first data set circuit. The cell further includes a differential clock circuit and a differential reset circuit. The clock circuit having complementary clock inputs to alternately set and store data in the data set and data store circuits. The differential reset circuit ties to the differential output and is operative in response to a reset signal to force the differential output to a predetermined logic level. The differential reset circuit includes matched complementary reset drivers to exhibit like capacitances. The slave cell is formed substantially similar to the master cell, and includes a second differential input coupled to the first differential output of the master cell.

Abstract: A trim bit circuit is provided that uses a cascoded differential PMOS EPROM with a fixed offset cross-coupled latch. The output sense signal is transferred by transmission gates to NMOS latched inverters. The output is buffered by another inventor. Programming is performed by a NMOS current sink that pulls the drain of the programmed (trimmed) PMOS EPROM device to ground. This places the full positive supply across the short channel trimmed device, the punchthrough inducing a trapped charge on the device. The reference (untrimmed) PMOS EPROM device is uncharged. Thus, the two PMOS EPROM transistors have unequal current. During the read mode, a replication bias voltage is induced by an external “read” power-on-reset circuit, thereby placing a few volts below positive supply on the gates of the cascode devices. This allows the Vds of the PMOS EPROM devices to increase to a little less than a volt.

Abstract: The number of good IC (Integrated Circuit) chips per wafer or time to print a wafer is optimized by examining a number of prospective chip-to-wafer offsets, and, for each offset, a number of prospective arrangements of reticle exposures (shot maps). Integrating such a shot map optimization sub-system with a reticle layout (frame generation) sub-system permits creation of an optimal shot map for an IC chip of known size. These two sub-systems can also be used iteratively to explore a range of possible chip sizes, presenting the results in a simple graphical form. The instant invention integrates shot map optimization, frame generation and chip size optimization/visualization into a single system, providing the chip designer with insight into the impact of chip size on manufacturability.

Abstract: A flip flop (30) comprising a master stage (34) comprising a first plurality of transistors (54, 56), wherein each of the first plurality of transistors comprises a selective conductive path between a source and drain. The flip flop also comprises a slave stage (42) comprising a second plurality of transistors (60, 62, 64, 66), wherein each of the second plurality of transistors comprises a selective conductive path between a source and drain. For the flip flop, in a low power mode the flip flop is operable to receive a first voltage (VDD) coupled to the selective conductive path for each of the first plurality of transistors. Also in the low power mode, the flip flop is operable to receive a second voltage (VDDL) coupled to the selective conductive path for each of the second plurality of transistors. Lastly, the second voltage is greater than the first voltage in the low power mode.

Abstract: A dual rail flip flop with complementary outputs includes a master stage with embedded logic, a sensing stage, and one or more slave stages. The flip flop operates in a pre-charge state and an evaluate state. During the pre-charge state when a clock signal is low, the flip flop pre-charges internal keeper nodes to a high value. When the clock signal transitions high, the flip flop enters an evaluation state and one of the internal keeper nodes evaluates to a low value. The sense stage senses which of the internal keeper nodes is evaluating to zero, and drives it to zero faster. The slave stages reflect the state of the internal keeper nodes during the evaluate state, and maintain their states during the pre-charge state.

Abstract: It is intended to provide a dynamic flip flop that prevents a floating signal from maintaining a voltage below a substrate voltage level in a P-type semiconductor substrate and that prevents a floating signal from maintaining a voltage exceeding the substrate voltage level in an N-type semiconductor substrate. In the dynamic flip flop, an N-type MOSFET (5) controlled by an output signal MX from an inverter (2) and an N-type MOSFET (6) controlled by an output signal Q from an inverter (4) are provided as switches for short-circuiting a signal M and a signal QX to be brought into a floating state to a substrate.

Abstract: A device and method for improving the synchronization and metastability resolving capabilities of a flip flop. At least one master latch resolves a metastable condition of a received data signal thereby generating a stable data signal which is received and then displayed by a slave latch. Latches with superior metastability time resolution are configured in a master-slave relationship along with a novel clocking scheme whereby the clock signal supplied to the master latch is inverted as compared to that which is supplied to slave latch. As a result, the input data is latched on a falling edge of a clock signal and subsequently displayed on the rising edge of the clock signal providing at one half cycle for the input data to settle before passing out the data thereby allowing metastabilities to resolve during that period.

Abstract: Flip-flops include a master stage and a slave stage. The master stage is responsive to a first clock signal and has a first pair of differential inputs and a first pair of differential outputs. The slave stage is responsive to a second clock signal and has a second pair of differential inputs coupled to the first pair of differential outputs and a second pair of differential outputs from which true and complementary outputs (Q, QB) of the flip-flop are derived. If the flip-flop is a D-type flip-flop, the first pair of differential inputs receive true and complementary data signals (DATA, DATAB). If the flip-flop is a set-reset (S-R) flip-flop, the first pair of differential inputs receive set and reset signals (SET, RESET).

Abstract: A data output method and data output circuit capable of increasing data output speed by reducing clock power while increasing sensing speed are provided. The data output method includes (a) precharging output terminals to a precharge voltage lower than a supply voltage; and (b) outputting differential output signals to the output terminals in response to differential input signals. In step (a) the output terminals are precharged in response to a clock signal having a first state, and in step (b) the differential signals are output to the output terminals in response to the clock signal having a second state. The voltage swing of the clock signal is set lower than the precharge voltage. The method further includes latching the differential output signals.

Abstract: Flip-flops include a master stage and a slave stage. The master stage is responsive to a first clock signal and has a first pair of differential inputs and a first pair of differential outputs. The slave stage is responsive to a second clock signal and has a second pair of differential inputs coupled to the first pair of differential outputs and a second pair of differential outputs from which true and complementary outputs (Q, QB) of the flip-flop are derived. If the flip-flop is a D-type flip-flop, the first pair of differential inputs receive true and complementary data signals (DATA, DATAB). If the flip-flop is a set-reset (S-R) flip-flop, the first pair of differential inputs receive set and reset signals (SET, RESET).

Abstract: A sampling receiver includes: at least one slave latch circuit; and at least one master latch circuit which further includes: at least one differential input transistor pair, and at least one bistable circuit. Output terminals of the at least one differential input transistor pair and output terminals of the at least one bistable circuit are coupled to the at least one slave latch circuit but in parallel to each other with reference to the at least one slave latch circuit for the purpose of reducing an output impedance to allow the sampling receiver to exhibit a high speed latch operation.

Abstract: A latch chain having improved input voltage sensitivity. The chain includes a first latch, an amplifier, and a second latch connected in series. The second latch is a conventional latch. The first latch is modified to have a higher sensitivity and lower output voltage swing than conventional latches. The modified latch includes a pair of matched output transistors that generate output voltages and a pair of matched biasing circuits to bias the bases of the output transistors with bias voltages. A sample stage is connected so as to apply first biasing currents to one of the biasing circuits in response to input voltages applied to the first latch during the sample period. In addition, a hold stage is connected so as to apply second biasing currents to the biasing circuits during a hold period. The sample and hold stages are configured to apply different voltage differences between the bases of the output transistors.

Abstract: A master-slave flip-flop includes a master section to receive an input signal, and first and second slave sections coupled to the master section. The first and second slave sections output respective true and complementary output signals. The first and second slave sections are furthermore identical, and coupled to common clock signals so that respective the first and second slave sections latch inputs from the master section simultaneously. In this way, the true and complementary output signals of the master-slave flip-flop are non-skewed relative to each other.

Abstract: A latch circuit for temporarily storing an input signal and successively outputting the input signal is disclosed, that comprises an input transfer circuit for inputting a reference clock signal, a first inverter for inverting an output signal of the input transfer circuit, a second inverter for inverting an output signal of the first inverter, and a hold transfer circuit for inputting an output signal of the second inverter and outputting it to the first inverter, wherein a second clock signal is input to the gate of the hold transfer circuit, the signal level of the second clock signal becoming high with a predetermined delay against a leading edge of the reference clock signal and becoming low corresponding to a trailing edge of the reference clock signal.

Abstract: The present invention discloses a novel method and system for accessing a semiconductor device at multiple operating speeds. The novel method and system of the present invention allows access to a semiconductor device by a pipeline circuit in which modification of the pipeline circuitry is not required to achieve multiple operating speeds. An example of the invention may be the utilization of an internal clock to control internal pipeline which may allow adjustment of an effective operating speed of a semiconductor device.

Abstract: A flip-flop circuit (100) that may have a reduced delay time between an edge of a clock input signal and a data output signal has been disclosed. A data signal may be received at a data input terminal (1), a clock input signal may be received at a clock signal input terminal (2), and data may be provided at a data output terminal (3). Data may be transferred from a master latch to a slave latch through a transfer circuit in response to an edge of a clock input signal. A transfer circuit may include a transfer device (6) which may have a control terminal connected to a clock signal input terminal (2) and a transfer device (5) which may have a control terminal connected to a buffered clock signal (C). In this way, delay time may be reduced while maintaining high-speed operations even if an input clock signal has a rounded or distorted waveform.

Abstract: A differential D flip-flop is disclosed including respective master and slave cells. The master cell comprises a first data set circuit and a first data store circuit. The data set circuit has a first differential input and a first differential output. The first data store circuit couples to the output of the first data set circuit. The cell further includes a differential clock circuit and a first current source for generating a fixed bias current in the master cell. The clock circuit having complementary clock inputs to alternatingly set and store data in the data set and data store circuits. The slave cell is formed substantially similar to the master cell, and includes a second differential input coupled to the first differential output of the master cell.

Abstract: A power efficient flip-flop includes a power switch regulating power supplied to a high speed latch in the flip-flop. When the power switch is activated, causing the high speed latch to receive power, the high speed latch captures data received by the flip-flop. The captured data is propagated by the high speed latch to the output of the flip-flop. Simultaneously, the high speed latch transmits the data to a low leakage latch connected to the high speed latch. Then, power is removed from the high speed latch, and the data retained in the low leakage static latch is now released to the output of the flip-flop. The power efficient flip-flop minimizes leakage current generated by the high speed latch by removing a path to ground when power is not provided to the high speed latch. A decoupling device is connected to the power switch to substantially eliminate a coupling effect.

Abstract: A dual rail flip flop with complementary outputs includes a master stage with embedded logic, a sensing stage, and one or more slave stages. The flip flop operates in a pre-charge state and an evaluate state. During the pre-charge state when a clock signal is low, the flip flop pre-charges internal keeper nodes to a high value. When the clock signal transitions high, the flip flop enters an evaluation state and one of the internal keeper nodes evaluates to a low value. The sense stage senses which of the internal keeper nodes is evaluating to zero, and drives it to zero faster. The slave stages reflect the state of the internal keeper nodes during the evaluate state, and maintain their states during the pre-charge state.

Abstract: A dual rail flip flop with complementary outputs includes a master stage with embedded logic, a sensing stage, and one or more slave stages. The flip flop operates in a pre-charge state and an evaluate state. During the pre-charge state when a clock signal is low, the flip flop pre-charges internal keeper nodes to a high value. When the clock signal transitions high, the flip flop enters an evaluation state and one of the internal keeper nodes evaluates to a low value. The sense stage senses which of the internal keeper nodes is evaluating to zero, and drives it to zero faster. The slave stages reflect the state of the internal keeper nodes during the evaluate state, and maintain their states during the pre-charge state.

Abstract: An improved flip-flop circuit exhibits a higher phase margin than conventional flip-flop circuits without a substantial increase in operating power. The flip-flop circuit includes a master latch circuit operatively coupled to a slave latch circuit. The flip-flop circuit uses any number of techniques to delay the hold-to-sample transition of the slave latch circuit relative to the sample-to-hold transition of the master latch circuit. The delay enables the flip-flop circuit to better tolerate clock/data timing alignment issues. In a first embodiment, the slave clock signal is delayed relative to the master clock signal. In a second embodiment, the master clock signal buffer is unbalanced such that its duty cycle is skewed to produce unequal sample and hold periods. In a third embodiment, the master latch circuit is unbalanced to create an unequal delay associated with the sampling and holding periods.

Abstract: A flipflop has master and slave interconnected through a buffer. The master has its inverters located outside the signal path from input to output, as the buffer provides the driving capability required for both IDDQ-testing and operational use. This configuration enables IDDQ-testing without further circuitry added to the flipflop and reduces propagation delay in the signal path.

Abstract: A master-slave flip-flop circuit (200, 200′) includes a master latch circuit (202) and slave latch circuit (203). A hold control component (220) included in the master latch circuit (202) is interposed between a master latch node (ML) and a slave input node (SI). The hold control component blocks the transfer of data from the master latch node (ML) to the slave input node (SI) in response to a hold input. In the preferred form of the invention of the hold control component (220) comprises a tri-state inverter having an input connected to the master latch node (ML) and an output connected to the slave input node (SI). The hold input, comprising a high level hold signal and its complementary or inverted signal, disables the tri-state inverter and thus prevent data from being transferred from the master latch node (ML) to the slave input node (SI).

Abstract: Flip-flop circuits FF1 to FF6 are each constructed as a pair of cascade connected latch circuits 21 and 22 in an arbitrarily combination. The latch circuits L1 and L2 each comprises an input stage push-pull circuit PP and an output stage hold circuit HD as CVSL circuit. The latch circuit L1 includes an input stage having two pairs of nMOSTs 2 to 5 receiving input data DP and DN inputted thereto and connected in series each and in parallel connection of the pairs and a pair of nMOSTs 1 to 6 receiving a clock CP inputted thereto and connected to the opposite sides of the parallel connection. The output stage hold circuit HD includes a CVSI circuit having two pairs of nMOSTs 7 and 10 and a pair of pMOSTs 12 and 13 and an nMOST 11 receiving a clock CN inputted thereto. Thus obtained flip-flop (FF) circuit permits construction of a high density semiconductor integrated circuit (IC) with fast operation and low power consumption.

Abstract: A data retention system has master-slave latches for holding data in an active mode; a data retention latch for preserving data read from the master latch in a sleep mode, which is connected to the master latch in parallel with the slave latch; a first multiplexer for receiving data externally provided and feedback data from the data retention latch, and selectively outputting either the data externally provided or the feedback data to the master latch in response to a first control signal; and a second multiplexer for transferring output data of the master latch to the slave latch and the data retention latch in response to a second control signal, wherein power for the data retention latch remains turned on in the sleep mode, while power for the data retention system except for the data retention latch is turned off.

Abstract: A differential cascode structure is configured to propagate a data state to a static latch at each active edge of a clock. A clock generator enables the communication of the data state and its inverse to the latch for a predetermined time interval. In a first embodiment, each cascode structure includes three gates in series, the gates being controlled by the clock signal, a delayed inversion of the clock signal, and the data state or its inverse. In an alternative embodiment, each cascode structure includes two gates in series, the gates being controlled by the clock signal and the delayed inversion of the clock signal. In this alternative embodiment, each of these cascode structures is driven directly by the data signal or its inverse. The static latch obviates the need to precharge nodes within the device, thereby minimizing the power consumed by the device. The latch preferably comprises cross-coupled inverters, which, being driven by the differential cascode structure, enhance the switching speed.

Abstract: A D-FF circuit for operating a master flip-flop and a slave flip-flop at each predetermined timing in accordance with a plurality of clock signals generated by a clock signal generating circuit, wherein the clock signal generating circuit generates the plurality of clock signals at different timings, the slave flip-flop starts operating in accordance with a clock signal which is generated at an earlier timing than another clock signal generated by the clock signal generating circuit, and the master flip-flop stops operating in accordance with a clock signal which is generated at a later timing than another clock signal generated by the clock signal generating circuit.

Abstract: A bi-directional shift register comprises flip-flops connected to first switches and second switches. Third switches are connected in sequence and between the respective flip-flops. The third switches are on-off controlled in accordance with a CLK signal in order to periodically transition from low to high or from high to low. The shift register opens the second switches during the low duration of the REV signal and opens and closes the first switches in accordance with clocking of the CLK signal to shift data in the forward direction. The shift register opens the first switches during the high duration of the REV signal and opens and closes the second switches in accordance with the clocking of the CLK signal to shift data in the reverse direction.

Abstract: In a scan flip-flop circuit, a first master latch circuit receives usual mode data at a usual data input terminal in synchronization with a first clock signal. A second master latch circuit receives scan-in data at a scan-in data input terminal in synchronization with first and second scan clock signals. A slave latch circuit receives an output signal of the first master latch circuit in synchronization with said first clock signal and the second scan clock signal. The slave latch circuit is constructed by a control circuit for controlling transfer of the usual mode data to the output terminal in synchronization with the second scan clock signal.

Abstract: A latch and a D-type flip-flop capable of realizing high speed operation and capable of achieving a reduction of power consumption, wherein in a master side latch, a first NMOS transistor always in the ON state is provided as a first parallel resistor means connected in parallel with a second NMOS transistor (serving as the first input discriminating means) receiving a data input signal D, and a third NMOS transistor always in the ON state is provided as a second parallel resistor means connected in parallel with a fourth NMOS transistor NT114 (serving as the first input discriminating means) receiving an inverted data input signal DX. By this, without enlarging the transistor sizes of the second and fourth NMOS transistors, an equivalent combined resistance of discharge paths can be reduced by these parallel resistor means, a high speed operation can be realized, and a lowering of a power consumption can be realized.

Abstract: A pipelined four-to-two compressor includes sequential elements with embedded logic. One sequential element is a flip flop with complementary outputs that includes a master stage with embedded logic, a sensing stage, and one or more slave stages. The flip flop operates in a pre-charge state and an evaluate state. During the pre-charge state when a clock signal is low, the flip flop pre-charges internal keeper nodes to a high value. When the clock signal transitions high, the flip flop enters an evaluation state and one of the internal keeper nodes evaluates to a low value. Keeper nodes can also be dynamic flip flop outputs that pre-charge each clock cycle. Another flip flop with embedded logic receives the dynamic output, applies further logic, and provides a static output.

Abstract: A fully differential double edge triggered flip-flop stores and outputs first and second fully differential input values on leading and trailing edges of a clock. The flip-flop includes a first fully differential master circuit, a second fully differential master circuit and a fully differential slave circuit. The first master circuit stores the first input value during the period from the leading edge to trailing edge of the clock. The second master circuit stores the second input value during the period from the trailing edge to leading edge of the clock. The slave circuit is electrically connected to outputs of the first and second master circuits. The slave circuit includes a second repeater as an output end of the flip-flop, outputs the first input value on the trailing edge of the clock, and outputs the second input value on the leading edge of the clock.

Abstract: An improved scan flip-flop and method of using same. The scan flip-flop has a separate dedicated scan output driven by a scan output signal driver. Scan shift race conditions are minimized by providing a weak scan output signal driver and inserting delay elements within a cell for a scan flip-flop in the scan signal path. The use of the improved scan flip-flop allows for a one-pass scan synthesis process which provides accurate flip-flop cell timing and area information during the design process.