Abstract: A scan chain element in an integrated circuit, the scan chain element including; a first latch connected to accept test data as an input, a second latch connected to accept the output of the first latch as an input, control logic for accepting a clock signal and a hold signal, the scan chain element being operable in a first mode such that the control logic is configured to supply the clock signal to the first latch and subsequently, in response to the hold signal, to supply the clock signal to the second latch to latch the data from the output of the first latch.

Abstract: In a low power consumption mode in which prior data is retained upon power shutdown, the return speed thereof is increased. While use of an existent data retaining flip-flop may be considered, this is not preferred since it increases area overhead such as enlargement of the size of a cell. A power line for data retention for power shutdown is formed with wirings finer than a usual main power line. Preferably, power lines for a data retention circuit are considered as signal lines and wired by automatic placing and mounting. For this purpose, terminals for the power line for data retention are previously designed by providing the terminals therefor for the cell in the same manner as in the existent signal lines. Additional layout for power lines is no longer necessary for the cell, which enables a decrease in the area and design by an existent placing and routing tool.

Abstract: The present invention relates to a differential coder (10) for electrical signals comprising control means (21, 22) and a bistable T adapted to deliver an output binary data signal (S, S*). The bistable T comprises a master bistable (11) followed by a slave bistable (12), each bistable having a main control input (E1, E2). The differential coder is integrated and said control means comprise a first circuit (21) dedicated to the master bistable and adapted to supply said master control signal (A) injected into the main control input of the master bistable and a second circuit (22) dedicated to the slave bistable, controlled by said clock signal (CK) and adapted to supply a slave control signal (CK2) that is representative of a signal that is complementary to the clock signal and is injected into the main control input of the slave bistable.

Abstract: A system for reducing current leakage in an integrated circuit. The system includes a first circuit component and a second circuit component in a path between a high voltage state and a low voltage state, such as ground. A feedback mechanism selectively provides feedback from an output of the second circuit component to an input of the first circuit component to selectively cutoff the path at the first circuit when the path is not cutoff at the second circuit. In a more specific embodiment, feedback mechanism preserves data in the integrated circuit via a multiplexer that selectively enables the feedback when the integrated circuit is in sleep mode. The first and second circuit components are High Voltage Threshold (HVT) CMOS inverters. The feedback path is chosen so that when the feedback path is activated, leakage paths through the CMOS inverters are cutoff.

Abstract: Systems and methods provide metastability-resistant techniques. For example, in accordance with an embodiment of the present invention, a flip flop is disclosed having a dynamic gain skewed to provide metastability resistance.

Abstract: A flip flop includes a master portion operable to latch at least one of an input signal and an inverted input signal. The flip flop also includes a slave portion operable to latch at least one of the signal latched by the master portion and an inverted signal latched by the master portion in response to a first phase of a clock signal. The slave portion is also operable to be reset in response to a second phase of the clock signal.

Abstract: A master-slave-type scanning flip-flop circuit is capable of operating at a higher speed by reducing a load capacity of a clock controller. The master-slave-type scanning flip-flop circuit is used to test a semiconductor integrated circuit device, and has a master latch and a slave latch each for temporarily holding an input signal, a first scan controller, a clock controller, and a second scan controller. The first scan controller receives an output signal from the master latch and outputs the received output signal in synchronism with a scan clock which is a clock for testing the semiconductor integrated circuit device, when the semiconductor integrated circuit device is tested. The clock controller receives an output signal from the first scan controller and outputs the received output signal to the slave unit in synchronism with a predetermined clock when in a normal mode of operation.

Abstract: An embodiment of a ultra low-power data retention latch circuit involves a slave latch SL that concurrently latches the same data that is loaded into a main circuit (such as a main latch ML) during normal operation. When the circuit enters a low power (data retention) mode, power (VCC) to the main latch ML is removed and the slave latch SL retains the most recent data (retained data SA, SA-). When power is being restored to the main latch ML, the slave latch's retained data SA, SA- is quickly restored to the main latch ML through what constitute Set and Reset inputs SAR, SAR- of the ML. This arrangement ensures that data restoration is much quicker than conventional arrangements that require the output data path DATA- to be stabilized before power is re-applied to the main latch. Further, there is no need to wait for power to the ML to be stable before restoring data from the SL to the ML, providing an increase in data restoration speed over conventional data retention latches.

Abstract: A data storage element for use in LSSD compliant circuit designs. The data storage element has an alternate, or scan, data input circuit that has increased immunity to electrical noise while maintaining lower power consumption than the circuits used for primary data input. This increased noise immunity reduces the probably that noise on the alternate data input will cause an unintended change of data state stored in the data storage element. Modification of latch circuits used in the data storage element allow a reduction in the number of transistors used in the latch circuits, thereby compensating for the increase in transistors used in the alternate data input circuit and allowing the data storage element to use the same number of transistors as prior designs that have less noise immunity on their alternate data inputs.

Abstract: A state saving circuit includes a state saving latch powered by an un-interruptible power supply, and a cut-off control device powered by the un-interruptible power supply that selectively connects the state saving latch to a pair of latch nodes based upon a control signal. The control signal determines whether the state-saving latch is in one of a state saving mode and a state restoring mode.

Abstract: An apparatus comprising a low voltage swing (LVS) circuit having a plurality of alternating LVS pre-charging and evaluation phases and a select logic circuit coupled to the LVS circuit and responsive to a plurality of input data signals to generate a plurality of select signals for the LVS circuit. Each of the select signals occurs during one of the LVS evaluation phases and has a turning-on edge and a turning-off edge. The turning-off edge of each of the select signals is generated independent of the input data signals.

Abstract: An dielectric laminated filter improves a skirt characteristic to shift am attenuation pole to a transmitting frequency band while maintaining the same band width of the transmitting frequency band and includes a dielectric block laminated with a plurality of dielectric sheets, ground electrodes formed on front and rear sides of the dielectric block, input and output electrodes formed on both sides of the dielectric body to be separated from the ground electrodes, an inductor pattern having two portions disposed parallel to the resonator patterns coupled to the input and output electrodes and a connecting portion coupling the two portions to induce an inductance coupling with the resonator patterns coupled to the input and output electrodes to improve a filter response characteristic by adjusting the inductance coupling.

Abstract: A flip-flop circuit with embedded scan capabilities uses a skewed latch to pull one end of the flip-flop either up or down while another end of the flip-flop is active. Further, the flip-flop is designed such that a data node and a scan node are coupled to a master stage, which contains the skewed latch. The data node and scan node values are initially generated from different ends of the flip-flop. Based upon clock dependencies and whether the flip-flop is in a normal mode or a scan mode, the master stage passes a value to a slave stage dependent upon the data node and scan node values. Thereafter, the slave stage outputs a result based on the value passed from the master stage.

Abstract: In the present invention, an input terminal of a flip-flop circuit in master slave form which is formed by connecting two inverters in a loop shape is connected to a first terminal via a first switch circuit, an output terminal of the flip-flop circuit is connected to a second terminal via a second switch circuit, a third switch circuit is provided between the path from the first switch circuit to the input terminal and the second terminal, a fourth switch circuit is provided between the path from the output terminal to the second switch circuit and the first terminal, and through turning ON the first and second switch circuits and turning OFF the third and fourth switch circuits the first terminal is rendered operable as an input terminal and the second terminal is rendered operable as an output terminal, and through turning OFF the first and second switch circuits and turning ON the third and fourth switch circuits the second terminal is rendered operable as an input terminal and the first terminal is rende

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 wireless communication apparatus, a wireless communication method thereof, and a wireless communication system employing the same. A master device of the wireless communication system requests one slave device of a network to perform a function of a master device for a predetermined time, and sends Piconet information about other slave devices of the network, while the one slave device receives the Piconet information from the master device and communicates with the other slave devices of the network for a predetermined time as a temporary master device. Accordingly, the one slave device becomes a dynamic master device and communicates with the other slave devices by using a frequency hopping sequence and a clock of a previous master device as they are, there is no need to transmit the frequency hopping sequence and the clock of the new master device to the slave devices, and accordingly, much time can be saved.

Abstract: The present invention provides a synchronizer for receiving an incoming data signal of a first clock domain and for outputting a data signal of a second clock domain. The synchronizer comprises an input stage, a master latch, a transfer stage and a slave latch. The input stage receives the data signal of the first clock domain and outputs the data signal to the master latch when the input stage is clocked with a master clock signal. The master latch stores the data signal at a storage node of the master latch. The master latch has a resolve time associated with it during which the master latch seeks to resolve the data signal to a logic 0 or a logic 1. The transfer stage transfers the data signal stored in the master latch to the slave latch when the transfer stage is clocked with a slave clock signal.

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: The present invention relates to a flip-flop circuit employing an MTCMOS technology comprising a master latch unit and a slave latch unit, for latching input data and outputting the data under the control of an internal clock signal, wherein an output of the flip-flop circuit retains a state just before the admission to sleep mode when the state of the system is converted from sleep mode to active by means of making a data state of an input terminal of a master latch into the same state as an inversed data state of an input terminal of a slave latch circuit in sleep mode and storing it. The flip-flop circuit employing the MTCMOS technology in accordance with the present invention is capable of retaining a state just before the sleep mode when the state of the system is converted from sleep mode to active mode by using the sleep mode control signal by means of adding the feedback circuit to the conventional flip-flop circuit.

Abstract: A clocked-scan flip-flop for multi-threshold CMOS (MTCMOS) is provided. The clocked-scan flip-flop includes a first switching unit which switches normal data that are input from the outside and outputs the data; a second switching unit which switches scan data that are input from the outside and outputs the data; a latch unit which latches the data input from the first switching unit or the second switching unit; and a clock input unit which controls the switching operations of the first and second switching units according to the result of a predetermined operation on a clock signal and a scan clock signal that are input from the outside. The clocked-scan flip-flop has the characteristics of a complementary pass-transistor (CP) flip-flop, that is, low power consumption and high performance. Also, the clocked-scan flip-flop provides a full-scale scan function for test purposes.

Abstract: A scannable storage circuit is provided that has a separate a scan output buffer for driving the scan output. The scan output buffer is coupled to the storage element in a parallel manner with the data output buffer so that normal data propagation is not delayed. The scan output buffer is gated by a scan enable input so that the scan output is quiescent when the storage circuit is not in scan mode. The selectively enabled scan output buffer is embodied with only four transistors.

Abstract: In response to a first transition of a clock signal, an information signal having a logic state is received. In response to a second transition of the clock signal, first circuitry latches a logic state of a first signal that indicates the information signal's logic state. In response to a third transition of the clock signal, second circuitry latches a logic state of a second signal that indicates the first signal's logic state. During a first mode of operation, power is supplied to the first and second circuitry. During a second mode of operation, power is reduced to the first circuitry, while power is supplied to the second circuitry, so that the first signal's logic state is lost, while the second signal's logic state is preserved.

Abstract: This invention describes circuit techniques providing a means for achieving reliable data retention and low leakage current in single step latches with switch transistors. The techniques require changes only in the circuit configuration. Neither higher cost technology such as multiple-threshold LVT/HVT transistors nor special control circuits are needed.

Abstract: A latch device is provided having a latch mode and a transparent mode. In the latch mode, the latch device synchronizes a data signal to a clock signal. In the transparent mode, the data signal drives the output without clock synchronization, such that the clock input signal is unused. The latch device can be employed in an optical driver for optical network laser diodes.

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 is disclosed. The flip-flop includes a first latch for receiving at least one bit and a second latch coupled to the first latch for storing the at least one bit from the first latch. The size of the second latch is minimized to reduce power consumption. The flip-flop also includes a multiplexor coupled to the first latch and to the second latch for outputting the at least one bit from the first latch, when a clock to the multiplexor is active and for outputting the at least one bit from the second latch when the clock is inactive. A system and method in accordance with the present invention optimize power consumption in a flip-flop through the use of a multiplexor for the output function. As a result, the size of the slave latch can be minimized, which reduces the overall power consumption of the device.

Abstract: A flip-flop circuit includes a latch that holds an input signal responsive to an internal clock signal, a comparing circuit that compares the input signal with a latch output to provide a comparison signal, and an internal clock generator that receives an external clock signal and generates an internal clock signal responsive to the comparison signal. The internal clock generating circuit performs a NAND operation on the external clock signal and a delayed inverted version of the external clock signal, to generate the internal clock signal having pulse width smaller than the external clock signal and having rising and falling edges synchronized with the external clock signal. Power consumption is low because the clock buffer and the internal clock generating circuit do not perform switching operations when there is little or no variation in the input signal of the flip-flop.

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 semiconductor integrated circuit device which shortens the time required for testing a divided logic circuit to reduce test cost and a fault-detecting method therefor. The logic circuit is divided into N logic blocks using N+1 scan paths comprises of scan flip-flops each having selectors for selectively picking up the output signals of storage elements which are fed back to the storage elements. A common scan operation may then be carried out on these logic blocks (Logic 1-to Logic N), and a testing operation may be continuously carried out on the logic blocks. The present invention preferably eliminates the overlaps in conventional scan operations, resulting in a shorter test time.

Abstract: A low power, high speed D type flip flop is disclosed. The D type flip flop uses four inverters and four transmission gates to store and output the data states. The flip flop comprises two memory elements wherein each memory element is made up of a transmission gate and two inverters. Each of the four inverters contained in the flip flop is referred to as a bypass current limiting inverter. Each of the four inverters contains biasing circuitry to limit current flow and thereby save power. Additionally, each inverter has switching circuitry that enables the current limiting features to be automatically and advantageously bypassed thereby allowing for large currents and fast response times whilst simultaneously retaining the low power performance.

Abstract: An integrated circuit including a Multi-Threshold CMOS (MTCMOS) latch combining low voltage threshold CMOS circuits with high voltage threshold CMOS circuits. The low voltage threshold circuits including a majority of the circuits in the signal path of the latch to ensure high performance of the latch. The latch further including high voltage threshold circuits to eliminate leakage paths from the low voltage threshold circuits when the latch is in a sleep mode. A single-phase latch and a two-phase latch are provided. Each of the latches is implemented with master and slave registers. Data is held in either the master register or the slave register depending on the phase or phases of the clock signals. A multiplexer may alternatively be implemented prior to the master latch for controlling an input signal path during sleep and active modes of the latch and for providing a second input signal path for test.

Abstract: A 2-input AND gate is inserted between an output terminal of a scan flipflop with an input selectable gate and a logic output signal line. The 2-input AND gate is controlled by a scan-enable signal line, and has a role to fix the transition of the output signal of the scan flipflop.

Abstract: A circuit and method reduces the number of nodes that must be forced during a standby mode when using clocked latches. The circuit and method can be used for half-cycle latches and full cycle latches in conjunction with alternate power-gated circuitry, even when many stages are cascaded in a pipeline structure. The data state on a single forcing node can be passed through one or more cascaded latch stages as well as through additional circuitry. By forcing latch transmission gates to be conductive during standby mode, multiple stages can be set to a specific state, as determined by an earlier stage being set by a forcing transistor. A clock generation. circuit and method is also provided for controlling transmission gates within the latches.

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 high-speed, noise-safe, non-inverting flip-flop (“flop”) is provided. In the flop, a buffer is used to isolate a data input terminal from the remainder of the flop circuitry to prevent erroneous operation of the flop circuitry. Also, a slave node is connected to a master node to avoid the need for an additional buffer on a data signal critical path, thus preserving the high-speed of the flop circuitry. Overlapped clock signals are used to control data signal transmission to the master node and the slave node. The overlapped clock signals allow the buffer used to isolate the data input terminal to also be used to drive the data signal through the master node to the slave node.

Abstract: A method and a flip-flop is disclosed in which power consumption is reduced in a standby mode. In a first aspect, the flip-flop comprises a first latch adapted to be coupled to a first power supply and a second latch coupled to the first latch and adapted to be coupled to a second power supply. The first and second power supplies are independently controllable to minimize power consumption in a standby mode. In a second aspect, a method for minimizing the power consumption of a flip-flop is also disclosed. The flip-flop includes a first latch and a second latch coupled thereto. The method comprises providing a first independently controllable power supply coupled to the master latch; and providing a second independently controllable power supply coupled to the slave latch. The method further includes reducing the voltage of at least one of the first and second power supplies responsive to the detection of a power saving mode.

Abstract: The circuit forms an edge-triggered D-Flip-Flop with a master/slave configuration. The master circuit has only one master switch controlled by a clock signal and followed by a first inverter. The slave circuit has a slave switch followed by a second inverter and a regenerative feedback-loop. The master and slave switches can easily be realized using n-MOS-transistors instead of transmission gates, thus achieving small chip area. The Flip-Flop can easily be amended by set and reset devices and it is suitable for mass applications such as memory and microprocessor chips.

Abstract: According to some embodiments, a circuit provides a first set of one or more flip-flops to receive a low-swing differential clock, and a second set of one or more flip-flops to receive the low-swing differential clock. One of the one or more flip-flops of the first set is to generate a first CMOS-level sampling pulse for each cycle of the low-swing differential clock, and wherein one of the one or more flip-flops of the second set is to generate a second CMOS-level sampling pulse for each cycle of the low-swing differential clock.

Abstract: A master latch implemented to receive feedback from a slave latch on a different input terminal than a input terminal on which data bits are received. Due to such receiving, the number of transistors/area and/or power consumption requirements (efficiently) may be minimized in implementing a flip-flop. The feedback path may be implemented using a single pass-gate, further enhancing the efficiency of implementation. In addition, clock enable/disable signals may be generated efficiently taking into account an externally received flip-flop disable signal and absence of transitions in the data input bits. When the flip-flop is implemented to support ATPG type sequential scanning testing, a multiplexor may be implemented efficiently to select either the data bits or scan bits.

Abstract: According to some embodiments, a circuit provides a first set of one or more flip-flops to receive a low-swing differential clock, and a second set of one or more flip-flops to receive the low-swing differential clock. One of the one or more flip-flops of the first set is to generate a first CMOS-level sampling pulse for each cycle of the low-swing differential clock, and wherein one of the one or more flip-flops of the second set is to generate a second CMOS-level sampling pulse for each cycle of the low-swing differential clock.

Abstract: A low power flip-flop is disclosed. The number of transistors which are coupled to the clock signal is reduced by more than half when compared with known flip-flop designs. The flip-flop comprises a pair of clocked transistors forming a pass gate and a plurality of inverters coupled thereto. By reducing the number of clock signal connections needed for reliable operation, the present invention reduces the power consumed by the flip-flop when operating at typical levels of activity by up to 70%.

Abstract: A system for reducing current leakage in an integrated circuit. The system includes a first circuit component and a second circuit component in a path between a high voltage state and a low voltage state, such as ground. A feedback mechanism selectively provides feedback from an output of the second circuit component to an input of the first circuit component to selectively cutoff the path at the first circuit when the path is not cutoff at the second circuit. In a more specific embodiment, feedback mechanism preserves data in the integrated circuit via a multiplexer that selectively enables the feedback when the integrated circuit is in sleep mode. The first and second circuit components are High Voltage Threshold (HVT) CMOS inverters. The feedback path is chosen so that when the feedback path is activated, leakage paths through the CMOS inverters are cutoff.

Abstract: The present invention relates to a flip-flop circuit employing an MTCMOS technology comprising a master latch unit and a slave latch unit, for latching input data and outputting the data under the control of an internal clock signal, wherein an output of the flip-flop circuit retains a state just before the admission to sleep mode when the state of the system is converted from sleep mode to active by means of making a data state of an input terminal of a master latch circuit into the same state as an inversed data state of an input terminal of a slave latch circuit in sleep mode and storing it.

Abstract: A master latch implemented to receive feedback from a slave latch on a different input terminal than a input terminal on which data bits are received. Due to such receiving, the number of transistors/area and/or power consumption requirements (efficiently) may be minimized in implementing a flip-flop. The feedback path may be implemented using a single pass-gate, further enhancing the efficiency of implementation. In addition, clock enable/disable signals may be generated efficiently taking into account an externally received flip-flop disable signal and absence of transitions in the data input bits. When the flip-flop is implemented to support ATPG type sequential scanning testing, a multiplexor may be implemented efficiently to select either the data bits or scan bits.

Abstract: A method and a flip-flop is disclosed in which power consumption is reduced in a standby mode. In a first aspect, the flip-flop comprises a first latch adapted to be coupled to a first power supply and a second latch coupled to the first latch and adapted to be coupled to a second power supply. The first and second power supplies are independently controllable to minimize power consumption in a standby mode. In a second aspect, a method for minimizing the power consumption of a flip-flop is also disclosed. The flip-flop includes a first latch and a second latch coupled thereto. The method comprises providing a first independently controllable power supply coupled to the master latch; and providing a second independently controllable power supply coupled to the slave latch. The method further includes reducing the voltage of at least one of the first and second power supplies responsive to the detection of a power saving mode.

Abstract: The invention relates to a semiconductor module having a plurality of signal paths for carrying external signals that each contain a setup and hold circuit on the basis of a latch circuit with a full latch and a logic circuit. The latch circuit contains at a beginning of the signal path upstream of the logic circuit a hold latch. The hold latch responds to the leading edge of a fast clock signal derived from the clock signal of the external signal, for the early latching of the external signal and for the decoupling of the hold time from the setup time. The full latch is disposed downstream of the logic circuit for the final latching of the external signal or of a signal derived from the latter.

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: A flip-flop is disclosed. The flip-flop includes a first latch for receiving at least one bit and a second latch coupled to the first latch for storing the at least one bit from the first latch. The size of the second latch is minimized to reduce power consumption. The flip-flop also includes a multiplexor coupled to the first latch and to the second latch for outputting the at least one bit from the first latch, when a clock to the multiplexor is active and for outputting the at least one bit from the second latch when the clock is inactive. A system and method in accordance with the present invention optimize power consumption in a flip-flop through the use of a multiplexor for the output function. As a result, the size of the slave latch can be minimized, which reduces the overall power consumption of the device.

Abstract: An apparatus to overcome a metastable state in a communication system employing a common clock period includes a first latch and a second latch, the first latch being clocked by a clock signal and the second latch being clocked by an inverted version of said clock signal, each of the first and second latches receiving a data stream. A delay device delays the output of the second latch by one half of a cycle of the clock signal. A multiplexer outputs the output of the first latch when the received data stream does not exhibit metastability relative to the clock signal and outputs the output of the delay device in the presence of metastability. By latching the data according to the inverted clock, the data is not latched during state transitions thereof and metastability is avoided. The delay device re-synchronizes the latched data with the active edges of the clock signal.

Abstract: In a master latch circuit, input data signal is received in a data through state and is held in a data holding state as output data signal. In a slave latch circuit, the output data signal is received in a data through state and is held and output in a data holding state. In a circuit setting control unit, in response to a clock signal, the disconnection of a first line from a power source and the connection of a second line to a ground terminal in an NMOS transistor are performed to set the master latch circuit and the slave latch circuit to the data through state and the data holding state respectively, and the connection of the first line and the disconnection of the second line are performed to change the states of the latch circuits.