Abstract: Provided is a multi-threshold CMOS (MTCMOS) flip-flop for latching a data input signal in response to a clock signal and converting the latched signal to a data output signal.

Abstract: A method and apparatus are provided for performing on-board, in-circuit, and/or wafer level scan-based testing of integrated circuits. With the apparatus and method, one or more sequential storage elements, e.g., flip/flops, are coupled to combinational logic and are configured to have an additional port for receiving a scan mode signal. The scan mode signal sets the sequential storage element into one of two modes of operation: static mode in which the sequential storage element's output does not change on a falling edge of a scan enable signal or a transitional mode in which the sequential storage element's output is permitted to change on the falling edge. With sequential storage elements configured in this manner, a configuration scan is performed to set certain ones of the sequential storage elements into a static mode and other sequential storage elements into a transitional mode. A test pattern is then applied to the sequential storage elements and a pattern capture cycle is commenced.

Abstract: A threshold voltage of a transistor is fluctuated because of fluctuation in film thickness of a gate insulating film or in gate length and gate width caused by differences of used substrates or manufacturing steps. In order to solve the problem, according to the present invention, there is provided a clocked inverter including a first transistor and a second transistor connected in series, and a compensation circuit including a third transistor and a fourth transistor connected in series.

Abstract: A flip-flop having improved set-up time and a method used with are provided. The flip-flop comprises a first master latch, a first selector, a second master latch, a second selector, and a slave latch. The first master latch receives the critical data and is used to latch the critical data. The first selector receives a plurality of non-critical data and outputs a first selected data to the second latch. The second master latch is used to latch the first selected data. The second selector is coupled to the first master latch and the second master latch in order to output a second selected data to the slaver latch. The slave latch is used to latch and output the second selected data.

Abstract: The present invention provides a latch circuit that is operable to generate a pulse from first and second clock signals to allow gates in a datapath to propagate data with minimal latency. The first clock signal is a version of the system clock and the second control signal is a time-shifted, inverted version of the system clock signal. Each of the individual latches in a datapath comprises data propagation logic. In one embodiment of the invention, the data propagation logic uses the first and second clock signals to generate an “implicit” pulse. In another embodiment of the invention, the data propagation logic uses the first and second clock signals to generate an “explicit” pulse. The implicit and explicit pulses are used to control the transmission gate of the latch to provide propagation of data through the latch with minimal latency.

Abstract: A master latch (1) is formed from a static circuit, and a slave latch (2) is formed from a dynamic circuit. The number of circuit elements can be smaller as compared to a slave latch formed from a static circuit so that the size and area of a master-slave flip-flop can be reduced. Since the master latch is formed from a static circuit, data can be held stably during the standby time by setting the master latch in a data holding state.

Abstract: A semiconductor integrated circuit device has a normal operation mode and a scan test operation mode, and includes a pulse generating circuit and a scan flip-flop circuit. The pulse generating circuit generates pulse signals synchronized with a clock signal in each of the normal and scan test operation modes. The scan flip-flop circuit latches data in response to the pulse signals from the pulse generating circuit signal in each of the normal and scan test operation modes.

Abstract: The present invention includes a radiation hardened sequential circuit, such as a bistable circuit, flip-flop or other suitable design that presents substantial immunity to ionizing radiation while simultaneously maintaining a low operating voltage. In one embodiment, the circuit includes a plurality of logic elements that operate on relatively low voltage, and a master and slave latches each having storage elements that operate on a relatively high voltage.

Abstract: A data latch contains a supply connection, a reference ground potential connection and a data input. The input side of an inverter is connected to the data input, and it is coupled via a first switching device to the supply connection, and via a second switching device to the reference ground potential connection. Furthermore, a first multivibrator circuit having transistors of a first conductance type is provided, and is coupled to the supply connection. A second multivibrator circuit having transistors of a second conductance type is coupled to the reference ground potential connection. The transistors in the first and second multivibrator circuits in the data latch are connected to one another on the output side at a first node and at a second node, with the first node being connected to one output of the inverter, and the second node forming an output tap.

Abstract: A flip-flop is configured for low standby/leakage power for power-conservation, especially in battery operated portable devices using flip-flops. The flip-flop uses a clock and may be a D flip-flop, including a master latch with first and second inverters and a slave latch. The inverters in the master-latch are configured to be selectively gated. The gating is preferably done by first and second transistors receiving the clock signal and connected between a voltage source and the ground. The gating cuts off power supply to the inverters when the clock is low and reduces leakage power. The slave latch includes a primary inverter and a feedback inverter. Expediently, a transmission gate between the master-latch and the slave-latch is eliminated. The primary inverter in the slave-latch is not gated to prevent the input of the feedback inverter from going into a “floating” state.

Abstract: A device and associated method to reduce hold-time violations are disclosed. The device includes a latch module with a selectable delay. The latch module includes a control input to select the delay through the latch. In one embodiment, the delay of the latch is the time between when a latching edge of a clock signal is experienced by the latch until data changes at the output of the latch. In the event of a hold-time violation at latches that are downstream of other latches, a longer delay can be selected at an upstream latch to provide a slower delay path for data provided to the downstream latch violating the hold-time. By providing a slower delay path, the data being latched at the downstream latch will not change as quickly after a latching signal is received, and therefore the possibility of a hold-time violation is reduced.

Abstract: A latch circuit includes a feedback circuit having inverter circuits and at least two input terminals and an input circuit for inputting input signals or signals having the same phase as the input signals to the input terminals of the feedback circuit in synchronization with a clock signal. In the feedback circuit section, only when the input signals or the signals having the same phase as the input signals are input to the at least two input terminals at the same time, positive feedback using a predetermined number of amplification stages is applied to the input terminals.

Abstract: The invention discloses a frequency divider using half-adding functions, comprising one latch circuitry with half adding function for each digit, each latch circuitry receiving its output signal Sout at its S-input, the latch circuitry (76) for the least significant bit receiving at its Carry-input a “1”, and each further latch circuity receiving at its Carry-input the carry signal from the latch circuitry of the previous digit, and an And gate circuitry receiving the Sum outputs of the latch circuitries.

Abstract: An inexpensive, re-configurable storage circuit for programmable logic devices and application specific integrated circuits is disclosed. The storage circuit comprises: at least one output; and at least two inputs; and at least a one input and a two input response sequence, wherein the inputs change the output in a well defined response sequence; and a configuration circuit comprising one or more memory elements, wherein the memory bits are programmed to select one of said response sequences.

Abstract: A register circuit includes a passage control circuit and a holding circuit. The passage control circuit includes a first transistor having a gate to which a clock signal is input, a second transistor having a gate to which a data signal is input, and a third transistor having a gate to which a control signal is input, with source-drain paths of the first, second, and third transistors being connected in series. The passage control circuit enables passage of the data signal to the holding circuit according to a state of the clock signal when the control signal is in one of an active state and an inactive state, and disables passage of the data signal to the holding circuit when the control signal is in the other one of the active state and the inactive state. The holding circuit latches the data signal passed from the passage control circuit.

Abstract: A content addressable memory (CAM) system is disclosed including a dual mode cycle boundary latch (CBL). The CBL includes a master latch coupled to a slave latch. The CBL operates in a high speed functional mode and a lower speed test mode. In the high speed functional mode, input data bypasses the master latch and transports directly to the CBL output via the slave latch. The CBL effectively removes the master latch from the circuit in the high speed functional mode. However, in the lower speed test mode, input test data travels via both the master and slave latches to the CBL output.

Abstract: A digital storage element comprises a master transparent latch that receives functional data signals from data input ports and scan data signals from a scan input port, the data input ports coupled to a four-input, one-output multiplexer that receives the functional data signals and selectively outputs one of the functional data signals. The element comprises a slave transparent latch coupled to the master transparent latch and comprising dedicated functional and scan data output ports. While operating in a scan mode, a first clock signal is used by the slave transparent latch and a second clock signal is used by the master transparent latch, wherein the first and second clock signals are non-overlapping. A first transistor is coupled to the master transparent latch and a second transistor is coupled to the slave transparent latch. When activated, the first or second transistor resets the element.

Abstract: A edge triggered flipflop tolerates arbitrarily slow clock edge rates by utilizing complex gates, with weighted transistors, to electrically isolate the master latch from the data inputs, before the master latch and the slave latch are electrically connected together, and to electrically isolate the master latch from the slave latch, before the master latch and the data inputs are electrically connected together.

Abstract: A clocked level-sensitive scan design may have flip-flops designed to have data, scan-in, and output ports and to utilize two clock signals. Such a clocked level-sensitive scan flip-flop may be built utilizing two latches.

Abstract: Disclosed are methods and systems for implementing various circuitry within a high speed, high frequency signal environment such as an integrated circuit. In one embodiment, an improved clock tree mechanism utilizes multiple low power drivers to distribute a clock signal to various load cells. In another embodiment, a single circuitry in current mode logic is used to implement a combined multiplexer, buffer and level shifter. In other embodiments, improved static and partially static flip-flop circuitry is disclosed which uses fewer devices and less power than conventional circuitry while achieving the same functionality.

Abstract: A multi-threshold flip-flop includes a master latch, a slave latch, and at least one control switch. The master latch is composed of an input buffer formed with low threshold (LVT) transistors and a first latch circuit formed with LVT transistors. The slave latch is composed of a second latch circuit formed with high threshold (HVT) transistors and an output driver formed with LVT transistors. The at least one control switch enables or disables the LVT transistors and is implemented with at least one HVT transistor. The LVT and HVT transistors may be N-FETs and/or P-FETs. The multi-threshold flip-flop can operate at high speed, has low leakage current, and can save the logic state when disabled.

Abstract: An area optimized edge-triggered flip-flop for high-speed memory dominated design is provided. The area optimized flip-flop also provides a bypass mode. The bypass mode allows the area optimized flip-flops to act like a buffer. This allows the area optimized flip-flop to provide the basic functionality of a flip-flop during standard operation, but also allows the area optimized flip-flop to act like a buffer when desirable, such as during modes of testing of the design. The area optimized flip-flop provides most of the functionality of a typical flip-flop, while reducing the total area and power consumption of the design.

Abstract: A flip-flop circuit arrangement and an associated method are disclosed, wherein a changeover between a master and a slave block is not effected by switching on and switching off respective current sources, but rather by impressing a compensation current that effects the changeover. One or more aspects of the present invention make it possible to reduce a supply voltage and at the same time, on account of low parasitic capacitances of the circuit, to provide a frequency divider in the gigahertz range which can be integrated using MOS circuit technology.

Abstract: A configurable latch comprises a dual master stages arranged in parallel to share a single output node. The configurable latch provides a single slave stage at the single output node to be shared between the two master stages. Pass gates controlled by various phases of an input clock, controls access to the slave stage by the two master stages. Additional control is added to configure the latch for positive edge triggered and negative edge triggered flip-flop functionality as well as level sensitive functionality. Chip enable, set, and reset are also provided for additional control.

Abstract: A static frequency divider circuit includes a first and second latch that are interconnected by a series path circuit and by a feedback path circuit. Each of the latches includes a reading BALLSACKbranch and a latching branch. The series path circuit includes a push-pull current driver to speed state transitions between the latching branch of the first latch and the reading branch of the second latch. Similarly, feedback path circuit includes a push-pull current driver to speed state transitions between the latching branch of the second latch and the reading branch of the first latch.

Abstract: The present invention discloses a flip-flop implemented with metal-oxide semiconductors using a single low-voltage power supply and a control method thereof, wherein an external control signal is input to a power switch in order to turn on the power switch for an active mode or to turn off the power switch for a sleep mode and inputting an external sleep control signal; the power switch is used to control a combinational circuit to enter into the active or the sleep mode, and the combinational circuit is connected to a virtual power supply; an internal clock signal is separately input to a master stage and a slave stage of the flip-flop, and whether to enter into the sleep mode or the active mode is determined by the voltage level of the internal clock signal. In the present invention, all the logic gates of the combinational circuit are formed of low-threshold CMOS's, which enables the present invention to maintain a given operation speed at a lower voltage.

Abstract: A low voltage logic circuit with asynchronous SET and/or RESET functions is described herein. The low voltage logic circuit may be primarily used in forming low voltage flip-flop circuits, but may also be used to form multiplexers and other logic configurations. The flip-flop circuit described herein improves upon existing low voltage architectures by providing a flip-flop circuit, which can operate at relatively low supply voltages (e.g., less than about 1.8V), with SET and/or RESET capability. In doing so, the improved flip-flop circuit may be used within a phase frequency detector, programmable counter, or frequency divider of a phase locked loop (PLL) or delay locked loop (DLL) device. However, the improved flip-flop circuit may be used with any low voltage circuit or device that may require, use or benefit from a SET or RESET function.

Abstract: A method and apparatus are provided for implementing AC power dissipation control during scan operations in scannable latch designs. A scannable latch has a functional data output and a scan data output. A switching control is provided with the functional data output. The switching control is driven to prevent switching of the functional data output during at least part of the scan operations. Then the switching control is disabled enabling switching of the functional data output during functional data operations.

Abstract: A CML master-slave latch incorporates logic into its master latching circuitry to incorporate a multiplexing function into the flip-flop. The multiplexing logic makes use of the pull-up loads and current source of the master latching circuitry. In this manner the pull-up loads and current source typically required for a stand-alone multiplexor are eliminated. Subsequently, the size of the present hybrid master-slave latch is smaller and consumes less power than a traditional combination of an independent multiplexor and master-slave latch. Since the master latching circuitry feeds only into the slave latching circuitry, the pull-up loads and the current sources of the master latching circuitry and slave latching circuitry may be optimized separately for achieving faster performance or less power consumption.

Abstract: Power consumption may be reduced through the use of power gating in which power is removed from circuit blocks or portions of circuit blocks in order to reduce leakage current. One embodiment uses a modified state retention flip-flop capable of retaining state when power is removed or partially removed from the circuit. Another embodiment uses a modified state retention buffer capable of retaining state when power is removed or partially removed from the circuit. The state retention flip-flop and buffer may be used to allow for state retention while still reducing leakage current. Also disclosed are various methods of reducing power and retaining state using, for example, the state retention flip-flops and buffers. For example, software, hardware, or a combination of software and hardware methods may be used to enter a deep sleep or idle mode while retaining state.

Abstract: The application relates to a circuit for storing a signal during sleep mode, said embodiments of the circuit comprising: a sleep signal input operable to receive a sleep signal; a clock signal input operable to receive a clock signal; a plurality of latches clocked by said clock signal, at least one tristateable device clocked by said clock signal, said at least one tristateable device being arranged at an input of at least one of said plurality of latches, said at least one tristateable device being operable to selectively isolate said input of said at least one latch in response to a predetermined clock signal value; clock signal distribution means operable to distribute said clock signal to said plurality of latches and said at least one tristateable device; wherein in response to a sleep signal said circuit is operable to: reduce a voltage difference across at least a portion of said circuit such that said portion of said circuit is powered down; and maintain a voltage difference across at least one stora

Abstract: The invention relates to a shift register cell for safely providing a configuration bit having a master latch which can be connected to a serial data input on the shift register cell for the purpose of buffer storing a data bit; a first slave latch which can be connected to the master latch for the purpose of buffer storing the data bit; at least one second slave latch which can be connected to the master latch for the purpose of buffer storing the data bit, and having an evaluation logic unit which outputs the configuration bit on the basis of the data bits which are buffer stored in the master latch and in the slave latches. In addition, the invention provides a shift register for safely providing configuration bits which has a plurality of inventive shift register cells which are connected in series to form a shift register chain.

Abstract: A scannable latch is disclosed. The scannable latch includes a dynamic circuit, two cross-coupled NAND gates coupled to the dynamic circuit, and a pair of stacked transistors coupled to the dynamic circuit. One of the stacked transistors is for receiving data signals, and the other stacked transistors is for receiving scan in signals.

Abstract: In embodiments, a data-retention circuitry comprises data-retention inverters in a feedback loop, an isolation subcircuit to isolate the inverters from a pass-gate subcircuit in response to a sleep signal, and a supply-switching subcircuit to provide current to the data-retention inverters from a supplemental voltage supply through a well tap during a standby mode. The supply-switching subcircuit switches from a regular voltage supply to the supplemental voltage supply in response to the sleep signal.

Abstract: A method of power gating a latch including detecting a state of the latch, detecting a power gate signal, providing power to the latch while the power gate signal is negated, and removing power from the latch when the power gate signal is asserted and the latch is in a predetermined state. The method may include any one or more of pulling a node of the latch to a selected state while the power gate signal is asserted to ensure that the latch powers up in the predetermined state, providing a signal indicative of the latch state and the power gate signal to respective inputs of a logic gate having an output indicative thereof, switching a supply voltage to a power input of the latch based on a state of the output of the logic gate, and closing a switch to pull a node of the latch low.

Abstract: Data storage circuits and components of such circuits constructed using nanotube switching elements. The storage circuits may be stand-alone devices or cells incorporated into other devices or circuits. The data storage circuits include or can be used in latches, master-slave flip-flops, digital logic circuits, memory devices and other circuits. In one aspect of the invention, a master-slave flip-flop is constructed using one or more nanotube switching element-based storage devices. The master storage element or the slave storage element or both may be constructed using nanotube switching elements, for example, using two nanotube switching element-based inverters. The storage elements may be volatile or non-volatile. An equilibration device is provided for protecting the stored data from fluctuations on the inputs. Input buffers and output buffers for data storage circuits of the invention may also be constructed using nanotube switching elements.

Abstract: A high-speed gated flip-flop includes a latch configured to generate a data output signal (Q) in response to a data input signal (D) and a pair of true and complementary clock pulses (GCP,GCPB). These clock pulses are provided by a clock generator responsive to a periodic clock signal (CK). A control circuit is also provided. The control circuit is coupled to a feedback node (ND2) in the pulse generator. The control circuit configured to selectively enable the pulse generator in response to an enable signal (/EN). The pulse generator is configured so that an active transition of the true clock pulse (GCP) is fed back to the feedback node (ND2) in a manner that resets the pulse generator and terminates the true and complementary clock pulses in-sync with the active (e.g., low-to-high) transition of the true clock pulse (GCP).

Abstract: A latch circuit 2 is described including a function path latch 4, 6, which may be in the form of a standard flip-flop, together with a data retention latch 12, 14. The reset signal nreset and the scan enable signal SE are used to control these latches to perform reset, scan, save and restore functions. The save and restore functions serve to save a data value dv from the functional path latch 4, 6 into the data retention latch 12, 14 and restore this value such that the functional path latch can be powered down without a loss of data.

Abstract: A semiconductor integrated circuit device is provided with a diagnosis circuit, which does not increase the delay of a logic element in normal operation. In a latch provided at the output of a memory or at the input of a logic stage, a signal selector is provided in the feedback loop of the latch. The selector is switched in correspondence with the operation mode, such that it transfers the feedback signal in normal operation, while it transfers the test signal in a test mode, in order to prevent the delay from increasing in the signal selector on the main path in normal operation.

Abstract: Described herein is a latch circuit (110) which has an improved maximum toggle rate or frequency. The latch circuit (110) includes a first portion (116) and a second portion (62) in which input clock signals (52,54) are applied to respective input transistors (118,78). The input transistor (118) for the first portion (116) has an emitter area which is double that of the input transistor (78) for the second portion (62). This ‘imbalance’ between the two input transistors (118,78) provides an increase in the ‘hold period/follow period’ ratio such that it is greater than 1, the self-resonance of the latch circuit (110) and also maximum toggle rate or frequency.

Abstract: A differential register slave structure is presented. In one embodiment, a differential register includes a storage node (218, 318). The storage node (218, 318) stores and holds the differential values generated by the differential register. In one embodiment of the present invention, on power-up, when the state of various clocks (i.e., master, slave) in the differential register may be indeterminate, the storage node (218, 318) will discharge the differential values and the differential register will produce a differential output.

Abstract: A data path (200) can be configured to accommodate different clocking arrangements. In one mode, data values may be output at a single data rate: one data value every clock cycle. In another mode, data values may be output at a double data rate: two data values every clock cycle. A data path (200) can be compact circuit structure, needing only an additional mode multiplexer (206) and inverter over a conventional D-type master-slave flip-flop.

Abstract: A flip-flop (10) has a normal mode and a low power mode to save power. The flip-flop (10) has a master latch (14) and a slave latch (20). The slave latch (20) is used to retain the condition of the flip-flop (10) during the low power mode, where power is withdrawn from the master latch (14) but maintained on the slave latch (20). The slave latch (20) may use transistors with lower leakage characteristics than the transistors that make up the master latch (14). These lower leakage characteristics may be achieved by a higher threshold voltage and/or a thicker gate dielectric. Operating speed of the flip-flop (10) is maintained by implementing the slave latch (20) so that no logic gate or switching transistor is in the critical timing path. Instead, the slave latch (20) has an input/output terminal to tap into the signal path between the master latch and an output circuit (22).

Abstract: Each of D flip-flops (FFs) 13a to 13f constituting a scan path circuit has a normal operation input circuit to be selected in a normal operation and a test operation input circuit to be selected in a test operation, and a control signal having an intermediate voltage between a supply voltage and a ground voltage is sent from a voltage generating circuit 17 to the test operation input circuit of each FF in the test operation. In this case, the amount of an output change in data in each FF is smoother than that in the case in which the supply voltage is applied. Consequently, the delay time of the data is increased. The intermediate voltage to be applied to each FF in the test operation is determined based on a feedback signal sent from a test circuit 15 for checking whether scanned-out data have an error or not.

Abstract: A flip-flop circuit includes first and second logic gates, a first selection circuit and a latch circuit. The first logic gate executes a logic operation on a first data signal and a first control signal. The second logic gate executes a logic operation on a second data signal and the first control signal. The operation results of the first and second logic gates are forcibly fixed to a predetermined value irrespective of the first and second data signals, if the first control signal is asserted. A first selection circuit selects one of the operation results of the first and second logic gates, and outputs the selected operation result as a first selection signal. A latch circuit latches the first selection signal.

Abstract: A flipflop having a clock input for applying a clock signal, a data input for applying a data signal, a noninverting output and an inverting output, where the flipflop has a first holding element with a first feedback loop and a second holding element with a second feedback loop, where the first and second feedback loops each have a first node and a second node, where the first holding element is designed such that upon a first clock edge of the clock signal the logic value of the data signal is transferred to the first holding element and the logic value of the data signal is made available on the first node in the first feedback loop, where the first node in the first feedback loop is coupled to the first node in the second feedback loop in order to transfer the signal value which is on the first node in the first feedback loop to the second holding element upon a second clock edge of the clock signal and to output the signal value on the noninverting output, wherein the second node in the first feedback lo

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 method and apparatus of precharging data and/or address lines each having a large number of loads to a voltage midway between high and low using a source-follower configuration, and optionally driving only one-half of the precharge circuit based on a previous logical value on the line being precharged. In some embodiments, a driver circuit drives an output node either high or low during a first phase of each clock cycle, and a precharge circuit then precharges the output node to an intermediate voltage during a second phase of the clock cycle in preparation for the following clock cycle. Some embodiments include source-follower configured FETs to precharge, wherein these FETs turn off once the output voltage reaches an intermediate value.

Abstract: A flip-flop includes a clock signal input, a data signal input, non-inverting and inverting outputs, a data acceptance unit, and a storage unit having a feedback loop with first and second inverter circuits having feedback to one another. The inverting output is coupled to the first inverter circuit output and the non-inverting output is coupled to the second inverter circuit output. The acceptance unit, dependent upon the data and clock signals present, allocates a programming potential to the first or the second inverter circuit input and applies no potential to the respective other input of the circuits. The acceptance unit has a first switching element applying the predetermined programming potential to the input of the first inverter circuit dependent upon the clock and data signals and a second switching element applying the predetermined programming potential to the second inverter circuit input dependent upon the clock and data signals.

Abstract: An inexpensive, re-configurable storage device for programmable and application specific logic is disclosed. A configurable storage device comprising a storage circuit including at least one output and at least one input capable of changing said output in a well defined response sequence; and a configuration circuit including at least one memory element to control a portion of said storage circuit; and a programmable means of altering said storage circuit response sequence. This allows the user greater flexibility in picking the most desired flip-flop from a variety of choices. The user programmed flip-flop option converts to an application specific conductive pattern with no change in storage device performance.