Abstract: A clock dividing section receives a system clock and generates and outputs clock signals of two or more types. Selectors select any of the clock signals of two or more types outputted by the clock dividing section and feed it to a printing control block or reading control block. A decision divider monitors operational states of each block and gives control so that a frequency to be supplied to a functional block in an idle state where any operation is not required is lower than that to be supplied to a functional block being in an active state. Power consumption of the whole custom IC can be more reduced compared with a configuration wherein a clock of fixed frequency is constantly supplied to each functional block and a noise can be controlled.

Abstract: An electronic package and method for spatially distributing a clock signal is presented. The electronic package includes a low-loss structure, a semiconductor die, clocking vias, and clock receivers on the die. The low-loss structure is constructed and arranged to be driven by a clock signal and to produce standing waves. The clocking vias are constructed and arranged to connect the low-loss structure to the die and to conduct the standing waves to the die. The clock receivers generate respective synchronous on-chip clock signals based at least in part on the conducted standing waves.

Abstract: A clock driver chip has several banks of clock outputs driven by a single clock reference. Each clock output is driven by large pull-up and pull-down transistors, which have gates driven by pre-driver lines generated by a pre-driver circuit. Individual clock outputs, or a bank of outputs, are enabled by enable signals. A shorting switch is activated when enables for a pair of clock outputs are in a same state. The shorting switch has two transmission gates. One transmission gate shorts the pre-driver lines to the large p-channel transistors of the pair of outputs, while the other transmission gate shorts the pre-driver lines to the large n-channel transistors of the pair of outputs. Pre-driver lines to the pull-up transistors within a bank driven by the same enable can be hardwired together, as can the pre-driver lines to the pull-down transistors. Shorting switches can short banks together to reduce output skew.

Abstract: A method and apparatus provide power control for a multiple giga-hertz frequency integrated circuit. The method and apparatus include multiple levels of clock gating control circuitry and a clock distribution network to generate a low-skew system clock signal, and generate a gated clock signal, from the system clock signal, and distribute the gated clock signal to a plurality of local logic circuits in the integrated circuit.

Abstract: A semiconductor integrated circuit includes a clock signal source for generating two-phase clock signals having spacing periods, a two-phase clock wiring for transmitting the two-phase clock signals to a plurality of internal circuits constructing the integrated circuit, and a waveform correction circuit having a plurality of MOS transistors of the same conductivity type connected between the two-phase clock wiring and a preset potential node and constructed to attain spacing periods of the two-phase clock signals. The waveform correction circuit corrects the blunted portions of the two-phase clock signals to stably attain spacing periods, and when it is distributed and arranged in portions far apart from the clock signal source, a problem of racing and the like can be effectively suppressed.

Abstract: A system which simplifies the clock tuning process for a clock buffer tree. Essentially, a clock buffer tree is provided where the clock buffer tree includes clock buffers of different strengths. The different strength clock buffers which are in the clock buffer tree have the same pin-out configuration. Hence, it is easy and straightforward to upsize or downsize any of the clock buffers in the clock buffer tree, and it is guaranteed that the new cell will fit into the old cell's slot in the tree. Since none of the nets need to be modified, consistent timing results are achieved. Moreover, the new timing for the modified clock buffer can be anticipated because its wire loading does not change at all. The ease of clock tuning makes it much easier to design clock buffer trees and layouts, and allows the overall design to be completed faster and easier.

Abstract: An apparatus comprising an output connected to a plurality of inputs through a tree of connections. Each of one or more branches of the tree may be equidistant between the output and each of the plurality of inputs.

Abstract: A clock distribution tree for use with a semiconductor chip. The package for a semiconductor chip includes a clock distribution tree having a plurality of output terminals for connection to a plurality of input pads on a semiconductor chip. According to one embodiment, the semiconductor chip includes a clock receiving and conditioning circuit which is coupled to a clock input signal line. The clock receiving and conditioning circuit receives a clock signal, filters it, amplifies it and outputs it back to the package having a clock distribution tree thereon. The clock distribution tree thereafter distributes the clock signal to the appropriate locations of the semiconductor chip through clock output terminals coupled to clock input paths on the semiconductor chip.

Abstract: A technique for distributing common phase clock signals is disclosed. In one embodiment, the technique is realized by providing a forward traveling wave signal and a reverse traveling wave signal on a transmission line, wherein the forward traveling wave signal and the reverse traveling wave signal each have a common frequency and a constant relative phase. The forward traveling wave signal and the reverse traveling wave signal are each tapped off the transmission line at a plurality of different locations along the transmission line. The forward traveling wave signal and the reverse traveling wave signal that are tapped from the transmission line at each of the plurality of different locations are then combined so as to form a corresponding plurality of clock signals each having the common frequency and a common phase.

Abstract: A clock scheme for a system on a chip wherein integral sub-multiples of a system clock have positive edges on odd-numbered positive edges of the system clock and negative edges on even-numbered positive edges Data transfer between blocks of different frequencies is controlled by a state machine of the higher frequency block and can be achieved without elastic buffers and/or synchronizers.

Abstract: The present invention relates to a clock generator circuit which comprises a clock generator subcircuit which is operable to generate two clock signals having approximately the same frequency for use in sampling an analog signal in a generally alternating fashion. The clock generator circuit further comprises a pre-phase clock generator subcircuit associated with the clock generator subcircuit which is operable to generate two pre-phase clock signals, wherein each are associated with a respective one of the two clock signals generated by the clock generator subcircuit. In the pre-phase clock generator circuit, a signal transition of each of the pre-phase clock signals occurs before a signal transition of the respective clock signal generated by the clock generator subcircuit; in addition, a timing of a falling edge of the pre-phase clock signals is dictated by a global clock signal.

Abstract: A tapped phase shift ring oscillator may be used to provide multiple clock signals having variable phase delays. Phase delays may be selected to compensate for clock skews at different locations on high speed chips, or to provide clock signals having specific, desirable phase relationships, such as quadrature signals. The phase shift ring oscillator includes an odd number of amplifier stages. Each amplifier stage includes a phase shift network and an amplifier network. CMOS components used in the phase shift and amplifier networks provide voltage controlled variable phase shift and low gain, wide bandwidth, and low output impedance.

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

Abstract: A differential sinusoidal signal pair is generated on an integrated circuit (IC). The differential sinusoidal signal pair is distributed to clock receiver circuits, which may be differential amplifiers. The clock receiver circuits receive the differential sinusoidal signal pair and convert the differential sinusoidal pair to local clock signals. Power consumption and noise generation are reduced as compared to conventional clock signal distribution arrangements.

Abstract: A clock receiver circuit converts low amplitude, differential clock signal components received from a differential clock distribution medium into a full swing digital clock. The clock receiver circuit can be used as part of, for example, an on-die salphasic clock distribution system within a microelectronic device.

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

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

Abstract: A hierarchical clock distribution system includes a global clock grid that distributes a clock signal to a plurality of regional clock grids. Each of the regional clock grids then distributes the signal to a plurality of corresponding loads. The regional clock grids utilize salphasic clocking techniques to distribute the clock signal to the corresponding loads. The global grid achieves low skew based on the periodicity of the clock signal, rather than the dominance of a standing wave. The electrical distance to termination within the regional clock grids is preferably kept low to avoid the occurrence of phase change regions on the regional grids. In one approach, the regional grids are each driven at multiple points in a symmetrical fashion to reduce the electrical distance to termination.

Abstract: A system and method for providing redundant, synchronized clocks in a computer system. Upon a failure of a master clock signal, the system switches over to a slave clock signal synchronized with the master clock signal. Switching logic is coupled to receive a first clock signal and a second clock signal. The switching logic selects either the first clock signal or the second clock signal as a local clock signal. The switching logic further monitors the first clock signal for a failure. If a failure is monitored, the switching logic accepts the second clock signal as the local clock signal in place of the first clock signal. One or more clock local loads operate according to the local clock signal. The switching logic may control the input to a phase locked loop (PLL) that provides the local clock signal to the local clock loads. The method includes a PLL synchronizing an output clock signal with the master clock signal. The output clock signal is used by at least one local clock load for timing.

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

Abstract: A method and apparatus for generating a first clock signal and a second time staggered clock signal; and driving a first circuit with the first clock signal and a second circuit with the second time staggered clock signal, to cause unwanted signals due to the first clock signal and unwanted signals due to the second time staggered clock signal to occur at frequencies that are a multiple of the first clock frequency. The method and apparatus further comprising synchronizing outputs from the first circuit and the second circuit to facilitate transfer of information therebetween.

Abstract: In many electronic systems, it is common to communicate data from a transmitter in one device to a receiver in another. Accurate communications requires use of several matched clock signals. Mismatches in these clock signals cause transmitters to add “jitter” to transmitted data or receivers to be more intolerant of jitter in received signals, increasing the chances of mis-interpreting the data. Accordingly, the inventors devised an exemplary clock-distribution method which entails generating a base set of matched clock signals, deriving at least two separate sets of matched clock signals from the base set, and distributing one of the sets of clock signals to a set of matched components in a circuit and the other set of matched clock signals to a different set of components in the same circuit. The clock signals driving the matched components are isolated from mismatched aspects of the other components, and thus exhibit better matching.

Abstract: A hierarchical clock distribution system includes a global clock grid that distributes a clock signal to a plurality of regional clock grids. Each of the regional clock grids then distributes the signal to a plurality of corresponding loads. The regional clock grids utilize salphasic clocking techniques to distribute the clock signal to the corresponding loads. The global grid achieves low skew based on the periodicity of the clock signal, rather than the dominance of a standing wave. The electrical distance to termination within the regional clock grids is preferably kept low to avoid the occurrence of phase change regions on the regional grids. In one approach, the regional grids are each driven at multiple points in a symmetrical fashion to reduce the electrical distance to termination.

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

Abstract: A ladder type clock network for reducing the skew of clock signals is provided. The clock network includes a buffer for buffering a clock signal, first delay units for delaying the output of the first buffer by a set time, second buffers connected to respective outputs of the first delay units, and second delay units connected to respective outputs of the second buffers. The first delay units and the second delay units consist essentially of the resistance and capacitance of lines through which the clock signal propagates. Accordingly, the skew of the internal clock signals is reduced, and internal clock signals having a stable duty with respect to variations in a semiconductor device manufacturing process, temperature, and power supply voltage, are generated.

Abstract: Circuit for generating an inverse signal of a digital signal with minimal delay difference between the inverse signal and the digital signal. Two inverter circuits (6, 8; 7, 9) have been connected in series. The output signal of the second inverter circuit (7, 9) is the digital signal. An input signal for the first inverter circuit (6, 8) is supplied to a pass-through circuit (13, 14) with threshold action. The signal present between the first (6, 8) and the second (7, 9) inverter circuit is supplied to a control input (16) of the pass-through circuit with threshold action. The signal which is also present between the first (6, 8) and the second (7, 9) inverters appears with some delay at the output (17) of the pass-through circuit with threshold action, which signal is the inverse of the digital signal and at the same time constitutes the output signal of the pass through circuit (13, 14) with threshold action.

Abstract: The present invention comprises a system and method for flexibly distributing timing signals. Timing signals may require varying delays when connected, via circuit paths of varying propagation delays, to multiple circuit elements in order to preserve circuit synchronization. In one embodiment of the present invention, multiple clock signal generators are programmed to produce clock signals of differing time delays. This programming may be accomplished after the design and fabrication of the circuits utilizing the clock signals. These clock signals are then distributed, via circuit paths of varying propagation delays, to the multiple circuit elements.

Abstract: A clock splitter device for forming a clock/inverted clock signal pair. The input clock signal is sent through an initial buffer stage and applied to two parts of a second stage. The second stage includes a single stage buffer and constricted inverter to provide two inverted outputs. The transistor arrangement of these two parts provides an equal delay to the two signal paths. The outputs of these two parts are sent to identical output buffers. Because the two paths have identical transistor delays, and since the metal paths on the board are arranged to have identical delays, the two paths can very low skew therebetween.

Abstract: A clock signal generator which is particularly useful for a double data rate SDRAM (DDR-SDRAM) includes two or more clock signal input buffers and an enable signal input buffer. The clock signal generator generates internal clock signals that fluctuate at substantially different timings, yet the relationship between the internal clock signals with respect to validation and invalidation timing is constant. A latch circuit latches an enable signal from the enable signal buffer in accordance with a first internal clock signal from a first one of the clock signal buffers. A first enable signal connected to the latch circuit holds the latched enable signal in accordance with the first internal clock signal. A second enable circuit receives the first enable signal and the first internal clock signal and generates a second enable signal used to activate the clock signal buffers.

Abstract: A clock generating apparatus and method for generating clock signals of different frequency. The clock generating apparatus and method receives and divides a main clock signal to obtain a reference clock signal. Then, the reference clock signal and the first feedback clock signal are phase-locked to obtain the first clock signal. Moreover, the reference clock signal and the second feedback clock signal are phase-locked to obtain the second clock signal. The reset signal and the first clock signal are received by a divider. The divider then outputs the first feedback clock signal. Another divider receives the reset signal and the second clock signal and then outputs the second feedback clock signal.

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

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

Abstract: A clock splitter device for forming a clock/inverted clock signal pair. The input clock signal is sent through an initial buffer stage and applied to two parts of a second stage. The second stage includes a single stage buffer and constricted inverter to provide two inverted outputs. The transistor arrangement of these two parts provides an equal delay to the two signal paths. The outputs of these two parts are sent to identical output buffers. Because the two paths have identical transistor delays, and since the metal paths on the board are arranged to have identical delays, the two paths can very low skew therebetween.

Abstract: A clock splitter circuit for providing a single event upset (SEU) tolerant clock signal to latches in a space-based environment. The clock splitter circuit can include one or more event offset circuit delay circuits. The event offset delay receives a clock signal and generates a delayed clock signal. The event offset delay circuit can generate an inverted clock signal, a delayed inverted clock signal and a pair of intermediate clock signals. The delayed clock signal and inverted delayed clock signal can be delayed by the known duration of single event effects (SEE). The delayed and undelayed clock signals can be passed to an event blocking filter which can block any disturbance in the delayed and/or undelayed clock signals. A synchronizer can synchronize outputs of the event blocking filter prior to or coincident with being passed to corresponding inverting clock drivers. The synchronizers can also insure that the synchronized blocking filter outputs can not be low simultaneously.

Abstract: An apparatus and method for providing a gated output timing signal within a gated clock distribution tree. In accordance with the present invention, a gated clock splitter includes a timing signal input and a combinatorial logic block coupled to the timing signal input that generates a gated timing signal. A gating signal input is coupled to the combinatorial logic block for selectively enabling and disabling the output from the combinatorial logic block. A gate control circuit is coupled to the gating signal input for providing a gate signal to the combinatorial logic block, wherein the gate control circuit provides a full-cycle path for said gate signal to the gating signal input.

Abstract: The Sync State outputs are used in combination with the multiple phase outputs to generate and error signal which is operable to generate a control voltage which controls the frequency of the MVCO and to-generate a shifted clock which is divided in a sequential circuit to generate the quadrature clock with a frequency F.

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

Abstract: An integrated circuit receives an external clock signal and generates therefrom a clock signal that is supplied to a plurality of external devices. A delay-locked loop (DLL), a balanced clock tree, and a plurality of interface cells on the integrated circuit function together to supply the clock signal to the plurality of external devices such that the clock signal at each of the external devices is deskewed with respect to the external clock signal. Board level design is simplified because no balanced clock tree is needed to route the clock signal from the integrated circuit to the external devices, rather each external device is coupled to a corresponding one of the interface cells via a separate external connection. Each of these external connections has an equal propagation delay. One of the interface cells supplies the clock signal back to a reference signal input of the DLL via an external connection.

Abstract: A phase-locked loop (PLL) or a delay-locked loop (DLL) has differential delay stages with differential outputs driving differential clock inputs to a pair of differential toggle flip-flops. One flip-flop changes state on the rising edge and the other on the falling edge of the true output from the delay stage. Differential-to-single-ended buffers convert differential flip-flop outputs to single-ended multi-phase clocks. To avoid erratic or multiple oscillation and overtones, fewer than eight and preferably four differential delay stages are used. The delay stages are arranged in a twisted-ring with the differential outputs of the last delay stage crossed over and fed back to the differential inputs of the first delay stage. Tail currents of the delay stages can be adjusted by a voltage generated by a PLL loop. The differential toggle flip-flops allow for many taps or clock phases to be generated from the few delay stages.

Abstract: A clock forming unit, a selection processing unit, and a dithering control unit are provided. In the clock forming unit, m-phase clock signals whose phases are mutually deviated by a predetermined amount at a desired frequency are formed. The clock signals formed in the clock forming unit are supplied to the selection processing unit. A control signal is supplied from the dithering control unit to the selection processing unit. In the selection processing unit, by sequentially selecting one of the m-phase clock signals in response to the control signal from the dithering control unit, the phase is fluctuated forward and backward with a predetermined relation within a range of a precision that is permitted by a communication system serving as a supplying destination. A second clock signal in which a peak on a spectrum is spread is obtained from the selection processing unit.

Abstract: A load-insensitive circuit enables a global reference clock signal source of a synchronous multiprocessor system having a plurality of nodes to be “insensitive” with respect to the insertion or removal (“hot-swap”) of a load (such as a node) when the system is operational. The load insensitive clock source is provided through the use of a customized two-way passive radio frequency power splitter having an input port and two phase-matched output ports. A high degree of isolation is provided between clock signals delivered over the output ports when the input port of the splitter is properly terminated and embedded in a controlled impedance environment. Isolation is further enhanced by terminating each output port with a constant impedance comprising a precisely-matched, 50-ohm impedance load pad.

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

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

Abstract: A method and apparatus are provided for a high frequency, low power clock distribution within a very large scale integrated (VLSI) circuit chip. The apparatus for a high frequency, low power clock distribution within a very large scale integrated (VLSI) circuit chip includes a first clock circuit generating a first clock signal. A first level inverter is coupled to the first clock circuit receiving the first clock signal. A clock multiplier is coupled to the first level inverter, generating a multiplied clock signal. A plurality of inverters are coupled to the clock multiplier for driving logic circuits within the VLSI circuit chip at the multiplied clock signal.

Abstract: A semiconductor integrated circuit of the present invention includes: a plurality of areas which operate with independent clocks, respectively; and a phase separation element which differentiates the phase of one of the clocks from the phases of the other clocks and distributes the clocks to the areas, respectively. A clock distribution method of a semiconductor integrated circuit of the present invention includes: differentiating the phase of one of clocks from the phases of the other clocks; and distributing the clocks to areas, respectively, provided in a semiconductor chip and operating with independent clocks. A manufacturing method of a semiconductor integrated circuit of the present invention includes: forming a plurality of areas that operate with independent clocks to a semiconductor chip; and forming a phase separation element which distributes the clocks to the plurality of areas, respectively, with shifting phases by a length corresponding to a phase set for each of the areas.

Abstract: A multiphase clock generator includes oscillator, selector circuit and frequency divider circuit. The oscillator generates a first multiphase clock having a first phase difference. The selector circuit receives the first multiphase clock from the oscillator and outputs a second multiphase clock including a plurality of clock signals. In the second multiphase clock, the phase of each clock signal is shifted from that of the previous one by a second phase difference. The second phase difference is n times as long as the first phase difference, where n is a predetermined positive integer. And the frequency divider circuit receives the second multiphase clock from the selector circuit, divides the frequency of the second multiphase clock by a predetermined number and then outputs a group of clock signals with the divided frequency as a third multiphase clock.

Abstract: An apparatus, method and means for providing a clock signal and an inverted clock signal having corresponding rise and fall edge rates, being resistant to load variations, process variations, voltage variations, and temperature variations. The apparatus output exceeds a threshold voltage for apparatus circuit paths. In one aspect of the invention, a combination of N channel and P channel devices, viewed as symmetrical P stacks and N stacks, are utilized. Low output impedance and high gain is provided for resistance to load variations.

Abstract: An IC (Integrated Circuit) including internal circuitry to which a multiphase clock is distributed includes 1/n clock, main wiring drivers each including a frequency divider for dividing the frequency of an input clock by n and a drive circuit for delivering the resulting 1/n clock to a corresponding 1/n clock main wiring. Normal clock, main wiring drivers each include a delay for delaying an input clock to thereby output a normal clock and a drive circuit for delivering the normal clock to a corresponding normal clock main wiring. A clock distributing circuit includes clock wirings for distributing a clock input via a clock input circuit and a plurality of repeat buffers for distributing the distributed clock to each of the 1/n clock and normal clock, main wiring drivers. The IC additionally includes a wiring wiring the outputs of the repeat buffers, a wiring wiring the outputs of 1/n clock, main wiring drivers, and wiring wiring the outputs of the normal clock, main wiring drivers.

Abstract: A novel method and apparatus for eliminating shoot-through events during master-slave flip-flop scan operations to allow minimal test time of electronic circuit components is presented. Shoot-through scan problems introduced by loading mismatches on the TAP master and slave clock signal lines are solved by scanning an appropriate value into a programmable register, which increases the delay from master clock signal TCKM off to slave clock signal TCKS on and from slave clock signal TCKS off to master clock signal TCKM on.

Abstract: A clock architecture including a clock source, a multi-phase clock signal generator, a control bus, a number of clock signal lines, and at least one circuit block. The clock source generates a global clock signal, which is then transferred to the multi-phase clock signal generator connected to the clock source. Upon receipt of global clock signal, the multi-phase clock signal generator, which is connected to a control bus, generates clock signals of different phases according to the signals from the control bus. Each of the clock signal branches transfers one of the clock signals of different phases, wherein each of the clock signal branches is individually connected to the circuit block through an electrical switch. Only one switch is at an on state at one time, so that the clock signal of a corresponding phase is transferred to the circuit block. The driving forces applied on the clock buffer connected to the clock source and the clock buffers on the branches are adjustable for reducing clock skew.