Abstract: A frequency divider comprises a phase selector and a timing circuit. The phase selector is arranged to receive a plurality of input signals and a plurality of control signals and output a plurality of output signals according to the control signals, wherein a predetermined reference voltage and the input signals are selectively chosen to generate the output signals according to the control signals, and the input signals are of a same frequency but different phases. The timing circuit is arranged to receive the output signals and generate the control signals according to the output signals.

Abstract: The present invention discloses a method and apparatus for clock frequency division, the method comprises: determining a current frequency division coefficient in real time according to input clock signals and output clock information; then, performing counting on the input clock signals according to an integer portion and a decimal portion of the frequency division coefficient and a decimal scale threshold of the decimal portion; and performing accumulation on the decimal portion according to the counting result; finally, controlling the output clock according to the counting result and the accumulation result. With the method and the apparatus, output signals can be adjusted dynamically according to input signals, and the bit width of the integer portion and the decimal portion of the frequency division coefficient and the decimal scale threshold of the decimal portion can be increased on demand, so that the precision of the frequency division coefficient can be adjusted.

Abstract: Various apparatuses, methods and systems for frequency dividing a clock signal are disclosed herein. For example, some embodiments of the present invention provide an apparatus including a plurality of multiplexers connected in series with the clock signal, each having a plurality of inputs of different phase delays. The apparatus also includes a delta sigma modulator connected to control inputs on the plurality of multiplexers. The delta sigma modulator is adapted to repeatedly select different ones of the pluralities of inputs of different phase delays in the plurality of multiplexers to change a divide ratio between the clock signal and an output of the plurality of multiplexers. The apparatus also includes a multiplexer usage accumulator connected to the delta sigma modulator to track usage of the plurality of multiplexers.

Abstract: A direct digital frequency synthesizer having a multi-modulus divider, a numerically controlled oscillator and a programmable delay generator. The multi-modulus divider receives an input clock having an input pulse frequency fosc and outputs some integer fraction of those pulses at an instantaneous frequency fVp that is some integer fraction (1/P) of the input frequency. The multi-modulus divider selects between at least two ratios of P (1/P or 1/P+1) in response to a signal from the numerically controlled oscillator. The numerically controlled oscillator receives an accumulator increment (i.e., the number of divided pulse edges) required before an overflow occurs that causes the multi-modulus divider to change divider ratios in response to an overflow. The numerically controlled oscillator also outputs both the overflow signal and a delay signal to the delay generator. The delay signal contains phase-dithering noise that is induced by input from a pseudo-random noise generator.

Abstract: Systems and methods for providing a clock signal are provided. A frequency multiplier circuit is provided that can include a plurality of serially connected delay elements that are configured to generate a plurality of delay tap signals from an input signal. The frequency multiplier circuit can also include a phase detector configured to receive a first selected delay tap signal and the input signal. The phase detector can detect a phase shift between the first selected delay tap signal and the input signal, and can generate a phase detection signal indicative of a value of the phase shift. The frequency multiplier circuit can also include a digital logic gate configured to receive the input signal and a second selected delay tap signal. The digital logic gate can be further configured to generate an output signal responsive to the second selected delay tap signal and the input signal. The frequency multiplier circuit can also include a controller coupled to the phase detector and coupled to an output gate.

Abstract: A frequency divider having a plurality of programmable latches connected in a feedback shift register configuration. A programmable latch of said plurality of latches comprises a program input to receive a program signal configured to select a polarity of the programmable latch among two opposite polarities. The frequency divider having a configuration module structured to provide at least the program signal to the program input to modify a divisor parameter of the frequency divider.

Abstract: Example embodiments are directed toward configuration of a phase lock loop (PLL) circuits for low power operation. In particular embodiments, a fraction related to a desired gain of a PLL circuit is determined. A set of possible frequency-divider values and a set of possible feedback divider values are determined. A PLL configuration is selected from a combination of the sets of frequency divider and feedback divider values that forms a ratio indicated the determined fraction.

Abstract: Frequency division methods and circuits are provided for producing an output clock signal with a frequency related to the frequency of an input clock signal by a predetermined factor. The method and circuit rely on the input clock signal and on feedback from the output signal to produce an intermediate signal. The frequency of the intermediate signal is divided to produce the output clock signal. The method and circuit may be implemented using few circuit components. In an exemplary embodiment, the method and circuit may be used to produce an output clock signal with a frequency that is two-and-a-half times lower than the frequency of the input clock signal.

Abstract: Embodiments described herein are related to a counter. In some embodiments, the counter can be used as a divider, e.g., in a fractional PLL. In some embodiments, the counter (e.g., the main counter or counter C) includes a first counter (e.g., counter C1) and a second counter (e.g., counter C2), which, together with the first counter C1, perform the counting function for counter C. For example, if counter C is to count to the value N, then counter C1 counts, e.g., to N1, and counter C2 counts to N2 where N=N1+N2. For counter C1 to count to N1, N1 is loaded to counter C1. Similarly, for counter C2 to count to N2, N2 is loaded to counter C2. While counter C1 counts (e.g., to N1), N2 can be loaded to counter C2. After counter C1 finishes counting to N1, N2, if loaded, is available for counter C2 to start counting to this N2. Counters C1 and C2 can alternately count and thus provide continuous counting for counter C. Other embodiments and exemplary applications are also disclosed.

Abstract: Aspects of a method and system for use of true single phase clock (TSPC) logic for a high-speed multi-modulus divider in a phase locked loop (PLL) are provided. A fractional-N PLL synthesizer may comprise a divider that generates a divider signal from a VCO output reference signal. The divider may comprise at least one divider stage that utilizes true single phase clock (TSCP) logic D flip-flops. The first divider stage may operate at substantially the same frequency as that of the VCO signal. The divider may also re-synchronize the VCO signal and the divider signal by using at least two re-synchronization stages that utilize a TSCP logic D flip-flop and a stage for adjusting duty-duty cycle of the divider signal. The TSCP logic D flip-flops circuitry may be integrated with a two-input NAND gate or a three-input NAND gate to speed up the operation of the divider.

Abstract: A divider circuit includes a shift register which generates 2X (X is a natural number greater than or equal to 2) pulse signals in accordance with a first clock signal or a second clock signal and outputs them, and a divided signal output circuit which generates a signal to be a third clock signal with a cycle X times longer than a cycle of the first clock signal in accordance with the 2X pulse signals and outputs it. The divided signal output circuit includes X first transistors which control whether voltage of the signal to be the third clock signal is set to first voltage; and X second transistors which control whether voltage of the signal to be the third clock signal is set to second voltage.

Abstract: A frequency divider includes a first frequency divider stage coupled to a clock signal and operative to generate a first frequency divided signal. A second frequency divider stage is coupled to the clock signal and to the first frequency divider stage and is operative to generate a second frequency divided signal. A third frequency divider stage is coupled to the clock signal and to the second frequency divider stage and is configured to generate a third frequency divided signal using only i) the clock signal and ii) the second frequency divided signal so that any transition of the third frequency divided signal occurs at an edge of the clock signal at which the second frequency divided signal does not transition.

Abstract: Systems and methods for providing a clock signal are provided. A frequency multiplier circuit is provided that can include a plurality of serially connected delay elements that are configured to generate a plurality of delay tap signals from an input signal. The frequency multiplier circuit can also include a phase detector configured to receive a first selected delay tap signal and the input signal. The phase detector can detect a phase shift between the first selected delay tap signal and the input signal, and can generate a phase detection signal indicative of a value of the phase shift. The frequency multiplier circuit can also include a digital logic gate configured to receive the input signal and a second selected delay tap signal. The digital logic gate can be further configured to generate an output signal responsive to the second selected delay tap signal and the input signal. The frequency multiplier circuit can also include a controller coupled to the phase detector and coupled to an output gate.

Abstract: A clock frequency divider circuit in accordance with the present invention is capable of generating a clock signal that makes it possible to perform an expected proper communication operation in communication with a circuit operating by a clock having a different frequency, and includes a mask control circuit 20 and a mask circuit 10. The mask control circuit 20 includes a mask timing signal generation circuit 22 that generates a mask timing signal 29 used to preferentially mask a clock pulse at a timing other than communication timings among M clock pulses of the input clock signal based on a communication timing signal 26, and a mask restraint circuit 62 that carries out a process to restrain masking of a clock pulse at a communication timing. The mask circuit 10 generates an output clock signal by masking clock pulses of an input clock signal according to a mask signal 50 generated by the mask control circuit.

Abstract: A frequency synthesizer is provided, including a voltage-controlled oscillator (VCO), a frequency prescaler, a divide-by-2.5 circuit, and a selector. The VCO determine the frequency of a first signal according to an input voltage. The frequency prescaler determines the frequency of a second signal to be the frequency of the first signal divided by 3, 3.5, or 4 according to a first selection signal, and the frequency prescaler also determines the frequency of a third signal to be the frequency of the first signal divided by 6, 7, or 8 according to the first selection signal. The divide-by-2.5 circuit generates a fourth signal, wherein the frequency of the fourth signal is the frequency of the first signal divided by 2.5. The selector selects one of the second signal, the third signal, and the fourth signal as a fifth signal according to a second selection signal.

Abstract: To provide a clock frequency divider circuit that generates a clock signal enabling an expected proper communication in communication with a circuit operating by a clock having a different frequency. A clock frequency division circuit according to the present invention generates an output clock signal obtained by dividing a frequency of an input clock signal into N/S by subtracting (S?N) clock pulses from S clock pulses of the input clock signal based on a frequency division ratio defined as N/S. The clock frequency division circuit generates a control signal used to preferentially subtract a clock pulse at a timing other than a communication timing of data communication performed by a target circuit using the output clock signal among S clock pulses of the input clock signal. Further, it generates the output clock signal by subtracting a clock pulse of the input clock signal according to the generated control signal.

Abstract: A divide-by-three circuit includes a chain of three dynamic flip-flops and a feedback circuit of combinatorial logic. The divide-by-three circuit receives a clock signal that synchronously clocks each dynamic flip-flop. The feedback circuit supplies a feedback signal onto the first dynamic-flop of the chain. In a first mode, a signal from a slave stage of the first flip-flop and a signal from a slave stage of the second flip-flop are used by the feedback circuit to generate the feedback signal. In a second mode, a signal from a master stage of the first flip-flop and a signal from a master stage of the second flip-flop are used by the feedback circuit to generate the feedback signal. By proper selection of the mode, the frequency range of the overall divider is extended. Combinatorial logic converts thirty-three percent duty cycle signals from the flip-flop chain into fifty percent duty cycle quadrature signals.

Abstract: A frequency divider reduces jitter and power consumption, and includes a phase selector for receiving a plurality of clock signals and outputting an intermediate signal corresponding to phase characteristic of at least one of the clock signals, and an adjustable delay circuit for receiving the intermediate signal and generating an output signal by delaying the received intermediate signal.

Abstract: Embodiments of apparatuses, articles, methods, and systems for a synthesizer with an extended multi-modulus prescaler are generally described herein. Described embodiments include an offset controller that provides an offset to a first counter value and a multi-modulus prescaler to implement a first modulated division number based on the first counter value and a second counter value. The offset controller may compensate for the offset to provide a second modulated division number based on the first modulated division number. Other embodiments may be described and claimed.

Abstract: In a frequency dividing device, a 1/P frequency divider subjects an input clock signal to 1/P frequency division. A phase shifter shifts the phase of the 1/P frequency signal and outputs multiple different Q-phase signals. A switch controls phase shifting in accordance with a division ratio control signal, to switch the Q-phase signals from one to another. A 1/R frequency divider subjects the output from the switch to 1/R frequency division and outputs an Rth frequency clock signal. A ½ frequency divider subjects the Rth frequency clock signal to ½ frequency division and outputs a frequency divided clock signal. A division ratio setter receives a division ratio set signal and generates the division ratio control signal. As a division ratio, P×R×2?2×P/Q, P×R×2?P/Q, P×R×2, P×R×2+P/Q, and P×R×2+2×P/Q can be set.

Abstract: Systems and methods for providing a clock signal are provided. A frequency multiplier circuit is provided that can include a plurality of serially connected delay elements that are configured to generate a plurality of delay tap signals from an input signal. The frequency multiplier circuit can also include a phase detector configured to receive a first selected delay tap signal and the input signal. The phase detector can detect a phase shift between the first selected delay tap signal and the input signal, and can generate a phase detection signal indicative of a value of the phase shift. The frequency multiplier circuit can also include a digital logic gate configured to receive the input signal and a second selected delay tap signal. The digital logic gate can be further configured to generate an output signal responsive to the second selected delay tap signal and the input signal. The frequency multiplier circuit can also include a controller coupled to the phase detector and coupled to an output gate.

Abstract: A clock frequency divider for odd numbered divide ratios. The divider clocks two counters in parallel from a reference clock to be divided. One counter is loaded with the divide ratio and the other counter is loaded with the divide ratio except for the least significant bit. The second counter will set a latch when its count has elapsed. The first counter will reset the latch when its count has elapsed and will reload the counters. The latch is used for the divided output, but passes through a retiming circuit. The retiming circuit delays the output edge by one reference clock edge when the least significant bit indicates an odd numbered divide ratio.

Abstract: A clock generator is illustrated. The clock generator mentioned above includes a multimodulus frequency divider and a delta-sigma modulator. The multimodulus frequency divider is archived by switching the phase thereof. The multimodulus frequency divider increases the operating frequency of the clock generator effectively, and has a characteristic with half period resolution for reducing the jitter of an output clock signal when its spectrum is spread. Besides, the delta-sigma modulator increases the accuracy of the triangle modulation and reduces error of quantization by adding a few components therein. Thus, the clock generator could be expanded to a programmable clock generator.

Abstract: In one embodiment of the present invention, a clock generator circuit receives a clock signal having a period. The clock signal is employed by a digital circuit that is resident on the same substrate as an analog circuit, the digital circuit generates disturbance climaxes at clock edges that propagate through the substrate to the analog circuit. A clock generator circuit generates a plurality of clock signals, with each clock signal having a unique rate, wherein during a temporal gap, defined by the time between a last disturbance climax and a next sampling time of the clock signal, clock edges of any of the plurality of clock signals are avoided.

Abstract: A programmable divider apparatus comprises a first divider, a second divider, a feedback control unit, and a plurality of control signals. The first divider provides a frequency division operation of division by at least three integers, the second divider is cascaded to the first divider to provide a frequency division operation of division by two integers. The feedback control unit is coupled to between the first divider and the second divider to provide a feedback control signal to selectively supply an output of the second divider to an input of the first divider. The apparatus control signals and the feedback control signal are used to execute the first divider or the second divider.

Abstract: A phase locked loop frequency synthesizer with jitter compensation having a tapped delay line for compensating the jitter prior to passing a signal subject to jitter through a non-linearity; and, a ?? modulator for generating, or a storing element for pre-generated storing, of a fractional pattern representing fractional weighting of a plurality of integer divisors, wherein the fractional pattern identifies one integer divisor, out of the plurality of integer divisors, at a time to be active.

Abstract: A counter/divider where the counter/divider comprises a: a pre-scaler operable in a first mode to divide an input signal by M and in a second mode to divide the input signal by N, where N is greater than M; a first programmable counter, and a second programmable counter; and where the first and second programmable counters are responsive to an output of the pre-scaler and an output of the first counter controls whether the pre-scaler operates in the first mode or the second mode, wherein the first counter is operable to count to greater than one.

Abstract: In one embodiment, the present invention includes a frequency divider circuit for dividing the frequency of an input signal by an odd value. In one embodiment, a frequency divider circuit includes a counter configured to receive a clock input signal and a divisor having an odd value. The counter counts clock cycles up to the divisor to generate a count. A control circuit is configured to receive the count, the divisor, and the clock input signal and generate one or more control signals to control a state of a clock output signal. A half cycle adjust circuit is configured to receive the clock input signal and the one or more control signals from the control circuit and provide an additional one-half cycle adjustment of the clock output signal. The frequency divider circuit may be a feed forward circuit with fast startup characteristics.

Abstract: A frequency divider includes a transmission gate, a first inverter, a first switch circuit, a second switch circuit, and a second inverter. The transmission gate transmits a clock signal according to an inverted enable signal. The first inverter inverts the clock signal outputted from the transmission gate. The first switch circuit generates a first control signal according to the inverted clock signal and an output signal of the frequency divider. The second switch circuit generates a second control signal according to the clock signal, the inverted clock signal, and the first control signal. The second inverter inverts the second control signal to generate the output signal. The frequency of the clock signal is a multiple of the frequency of the output signal.

Abstract: Disclosed is a frequency divider including first to fifth FFs(flip-flops), each of which receives a common clock signal and samples and outputs an input signal responsive to an effective edge of the clock, an output signal of the 1st FF being supplied to the 2nd FF, a first logic gate which receives an output signal of the 2nd FF and a first control signal and outputs the output signal of the 2nd FF, when the first control signal is of a first value, and outputs a predetermined value, when the first control signal is of a second value, the output signal of the first logic gate being supplied to an input of the 3rd FF; a second logic gate which receives an output signal of the 1st FF and a second control signal and outputs an output signal of the 1st FF, when the second control signal is of the first value and outputs the predetermined value, when the second control signal is of the second value, the output signal of the second logic gate being supplied to the 4th FF; and a third logic gate which receives an o

Abstract: A mixer includes first and second differential input pairs that include first and second transistors. First and second bias transistors receive a first signal of a differential input signal that is the one of a first phase and a second phase, and that respectively communicate with first terminals of the first and second transistors of the first differential input pair. Third and fourth bias transistors receive a second signal of the differential input signal, and that respectively communicate with first terminals of the first and second transistors of the second differential input pair. First and second capacitive elements have first and second ends that respectively communicate with the first terminals of the first and second transistors of the first and second differential input pairs. Four current sourcing elements respectively communicate with first terminals of the first, second, third, and fourth bias transistors.

Abstract: A system and method are provided for jitter-free fractional division. The method accepts a first plurality of first signal phases, each phase having a first frequency. To make the division jitter-free, a phase is selected subsequent to deselecting a previous phase selection. The selected phase is divided by the integer N, supplying a second signal with a second frequency. Using the second signal as a clock, a first plurality of counts is triggered in series, and the counts are used to select a corresponding phase. The first signal may separate neighboring phases by 90 degrees. Then, for (N+0.25), a first count triggers a second count and selects the first phase, the second count triggers a third count and selects the second phase, the third count triggers a fourth count and selects the third phase, and the fourth count trigger the first count and selects the fourth phase.

Abstract: An embodiment of this invention combines feed-forward and feedback frequency division circuits in a such a way, to provide greater flexibility in choosing the non-integer division ratios at the output, with little added complexity. Alternate embodiments include additional divider(s) in signal or feedback paths providing additional flexibility and design simplification. An embodiment uses in-phase/quadrature signals to select the desired modes at feedback-path and signal-path mixers. Various alternatives are also described.

Abstract: This disclosure can provide methods, apparatus, and systems for dividing an input clock or master clock by an integer or non-integer divisor and generating one or more balanced, i.e., 50% duty cycle, divided that are phase-aligned to the input clock. The non-integer divisors can include half-integers, N/2, e.g. the division can be denoted 2:N. The value of N for each phase-aligned, balanced, divided clock can be distinct. The method can include generating an input clock signal having an input clock frequency, generating a secondary clock signal that transitions between a first state and a second state based on the input clock signal, generating a delayed secondary clock signal that is time delayed relative to the secondary clock signal, and generating the output clock signal that has a frequency that is a non-integer division of the input clock frequency.

Abstract: In a method for dividing a frequency of a clock signal, a first frequency divided signal is generated based on a clock signal. Rising edges in the first frequency divided signal are detected. Alternatively, falling edges in the first frequency divided signal are detected. An edge detection signal that includes a pulse for each detected edge is generated. A second frequency divided signal is generated based on the edge detection signal.

Abstract: Over the years, ring counter and prescalers have been used in a variety of microelectronic applications, including Phased Locked Loops or PLLs. All of these applications have experienced both decreases in size and increases in speed. As a result, current-mode logic or CML has come into use in some high speed applications, calling for alternative designs for components such as prescalers. Here, a divide-by-three prescaler is described that uses internal states from mater-slave flip-flop pairs and that is well-suited for microelectronics that employ CML.

Abstract: The present invention provides for a self-correcting state circuit. A first flip flop is configured to receive a clock input and a first data input, and to generate a first output in response to the clock input and the first data input. A second flip flop is coupled to the first flip flop and configured to receive the clock input and to receive the first output as a second data input, and to generate a second output in response to the clock input and the first output. A first correction circuit is coupled to the second flip flop and configured to generate a corrected output. A third flip flop is coupled to the first correction circuit and configured to receive the clock input and to receive the corrected output as a third data input, and to generate a third output in response to the clock input and the third data input.

Abstract: A multi-modulus divider and a method for performing frequency dividing by utilizing a multi-modulus divider are disclosed. The multi-modulus divider comprises a multi-modulus dividing circuit, a pulse generating circuit, and a modulus signal generating circuit. The multi-modulus dividing circuit comprises several serially connected divider cells, of which a predetermined one may be bypassed. The multi-modulus dividing circuit generates an output frequency according to an input frequency and a divisor. A range of the divisor comprises a plurality of numerical intervals. The pulse generating circuit generates a pulse signal. The modulus signal generating circuit generates a determination result by determining which numerical interval the divisor belongs to, and inputs, according to the determination result, the pulse signal into the predetermined divider cell to be one of references which the predetermined divider cell refers to when outputting a modulus signal.

Abstract: A direct digital frequency synthesizer having a multi-modulus divider, a numerically controlled oscillator and a programmable delay generator. The multi-modulus divider receives an input clock having an input pulse frequency fosc and outputs some integer fraction of those pulses at an instantaneous frequency fVp that is some integer fraction (1/P) of the input frequency. The multi-modulus divider selects between at least two ratios of P (1/P or 1/P+1) in response to a signal from the numerically controlled oscillator. The numerically controlled oscillator receives a value which is the accumulator increment (i.e. the number of divided pulse edges) required before an overflow occurs that causes the multi-modulus divider to change divider ratios in response to receiving an overflow signal.

Abstract: A frequency divider circuit comprises a plurality of T flip-flops, a first transmission gate, a second transmission gate and an inverter. The plurality of T flip-flops is connected in series. The output of the inverter is connected to a clock input of a first T flip-flop. The first transmission gate connects a clock signal and the other clock input of the first T flip-flop and the input of the inverter. The second transmission gate connects the inverted signal of the clock signal and the output of the first transmission gate.

Abstract: Frequency division methods and circuits are provided for producing an output clock signal with a frequency related to the frequency of an input clock signal by a predetermined factor. The method and circuit rely on the input clock signal and on feedback from the output signal to produce an intermediate signal. The frequency of the intermediate signal is divided to produce the output clock signal. The method and circuit may be implemented using few circuit components. In an exemplary embodiment, the method and circuit may be used to produce an output clock signal with a frequency that is two-and-a-half times lower than the frequency of the input clock signal.

Abstract: A programmable integer and fractional frequency divider is provided. The programmable divider divides a frequency of an input signal by a first divisor to generate an output signal, and comprises a programmable integer frequency divider and a fractional number switch. The programmable integer frequency divider divides the frequency of the input signal by a second divisor to generate the output signal, wherein the second divisor is first or second integers depending on a divisor switching signal. The fractional number switch calculates a pulse count of the output signal, and generates the divisor switching signal to switch from the first to the second integer when the pulse count of the output signal equals to a predetermined pulse count determined by a fractional part of the first divisor, and receives a fractional divisor control signal to change the predetermined pulse count, thereby changing the fractional part of the first divisor.

Abstract: The present invention relates to a unit counter block. According to an aspect of the present invention, the unit counter block includes a D-flipflop, a second MUX, and a first MUX. The-flipflop outputs first and second output signals in synchronism with a clock signal. The second MUX selects any one of external data and the second output signal of the D-flipflop in response to a data load signal and outputs a selected signal. The first MUX transfers any one of the first output signal of the D-flipflop and the output signal of the second MUX as an input signal of the D-flipflop in response to a counter enable signal or the data load signal.

Abstract: A binary frequency divider includes a counter paced by an input signal, means for comparing a counting value with first and second threshold values and supplying first and second control signals synchronized with variation edges of a first type of the input signal. The divider includes means for supplying at least one third control signal shifted by a half-period of the input signal in relation to one of the first or second control signals, and control means for generating the output signal using control signals chosen according to the value of at least one least significant bit of the division setpoint. Application is mainly but not exclusively to UHF transponders.

Abstract: A frequency divider in accordance with the present invention includes a plurality of latch circuits connected together in series to which a clock signal and an inversion clock signal are input, an inverter circuit to which an output signal from a last connected one of the latch circuits is input, an output terminal to which an output from the inverter circuit is connected, and a plurality of feedback paths that connect the output from the inverter circuit to respective inputs of the plurality of latch circuits. The frequency divider further includes a switching circuit that switches connections to the plurality of feedback paths so that an output signal from the inverter circuit is input to only one of the plurality of latch circuits.

Abstract: In one embodiment, the invention can be a clock-generating circuit having one or more clock-processing circuits, each outputting a clock signal having an adjustable phase. Each clock-processing circuit comprises a divider and a divisor control circuit. Each divider divides an input clock signal by a respective divisor value and outputs a corresponding output clock signal whose period is determined by the divisor value and the period of the input clock signal. Each divider receives the respective divisor value from the corresponding divisor control circuit, wherein the divisor value is selected in order to achieve a desired frequency and phase for the corresponding output clock signal. Temporarily changing a divisor value can advance or delay the phase of the corresponding output clock signal without having to reset the divider.

Abstract: The provided fractional frequency divider includes a divider controlling unit for generating a divider selection signal in response to a dual-edge triggering of an input signal and a frequency dividing unit coupled to the divider controlling unit for dividing the frequency of the input signal by one of an integer and a fractional dividers in response to the dual-edge triggering and the divider selection signal to generate the output signal of the fractional frequency divider. An operation of the frequency dividing unit is not suppressed when the integer divider is employed, the operation of the frequency dividing unit is not suppressed for a period of the input signal and is suppressed for half of that period, and this cycle is kept on recurring when the fractional divider is employed. The fractional-n PLL having the fractional frequency divider is also provided.

Abstract: A multi-modulus divider and a method for performing frequency dividing by utilizing a multi-modulus divider are disclosed. The multi-modulus divider comprises a multi-modulus dividing circuit, a pulse generating circuit, and a modulus signal generating circuit. The multi-modulus dividing circuit comprises several serially connected divider cells, of which a predetermined one may be bypassed. The multi-modulus dividing circuit generates an output frequency according to an input frequency and a divisor. A range of the divisor comprises a plurality of numerical intervals. The pulse generating circuit generates a pulse signal. The modulus signal generating circuit generates a determination result by determining which numerical interval the divisor belongs to, and inputs, according to the determination result, the pulse signal into the predetermined divider cell to be one of references which the predetermined divider cell refers to when outputting a modulus signal.

Abstract: A prescaler that operates in a broad band. The prescaler includes a buffer and a counter. The buffer includes a first amplification circuit, which has three inverter circuits of different drive capacities, a second amplification circuit, which has four series-connected inverter circuits, and a feedback circuit. One of the inverter circuits is connected between a capacitor and an inverter circuit via a first switch circuit and a second switch circuit. This varies the drive capacity of the first amplification circuit. The feedback circuit functions as a variable resistor having two transistors.

Abstract: A modulus divider stage (MDS) includes first and second stages. The MDS receives a modulus divisor control signal S that determines whether the MDS stage operates in a divide-by-two mode or a divide-by-three mode. The MDS stage also receives a feedback modulus control signal from another MDS. When in the divide-by-two mode, the MDS divides by two regardless of the feedback modulus control signal. To conserve power, the first stage is unpowered when the MDS stage operates in the divide-by-two mode. When in the divide-by-three mode, the MDS stage either divides by two or by three depending on the feedback modulus control signal. To further reduce power consumption, the first stage is unpowered when the MDS stage is in the divide-by-three mode but is nonetheless performing a divide-by-two operation. A power-down transistor holds the output of the first stage at the proper logic level when the first stage is unpowered.