Abstract: A prescaling stage includes bistable circuit in turn including respective master and slave portions inserted between a first and a second voltage reference and feedback connected to each other. Each portion is provided with at least one differential stage supplied by the first voltage reference and connected, by a transistor stage, to the second voltage reference, as well as a differential pair of cross-coupled transistors, supplied by output terminals of the differential stage and connected, by the transistor stage, to the second voltage reference. Advantageously, each master and slave portion includes a degeneration capacitance inserted in correspondence with respective terminals of the transistors of the differential pair.

Abstract: An injection-locked frequency divider includes a ring oscillator, a signal injection circuit, a first adjustable load circuit and a second adjustable load circuit. The ring oscillator generates an oscillation signal according to a differential signal outputted by the signal injection circuit. According to an adjustable voltage, the first and second adjustable load circuits can respectively change equivalent impedances of the first adjustable load circuit and the second adjustable load circuit so that a free-running frequency of the oscillation signal of the ring oscillator is adjusted and an injection-locked frequency range of the injection-locked frequency divider is expanded.

Abstract: It is an object of the present invention to provide a semiconductor device that has a simple circuit structure, a small scale, and low power consumption, and can generate a desired clock signal. The semiconductor device has a clock generation circuit which generates a clock signal by dividing a modulated carrier wave, a divider circuit which generates a first divided signal by dividing a carrier wave, and a correction circuit which generates a second divided signal by further dividing the first divided signal, and has a function of performing correction for inverting the second divided signal in a period corresponding to a half period of the clock signal during modulation of the carrier wave and selecting whether the correction is performed or not.

Abstract: A frequency divider for a wireless communication system is provided. A frequency divider includes a body bias voltage generator and a divider. The body bias voltage generator generates a body bias voltage including a PMOS body bias voltage and an NMOS body bias voltage whose voltage levels are controlled according to an input signal. The divider includes a plurality of flip-flops whose operation points are determined according to the body bias voltage, and generates an output signal by dividing a frequency of the input signal by N. Each of the flip-flops may include a PMOS logic and an NMOS logic. The PMOS logic may include a plurality of PMOS transistors whose operation points are determined according to the PMOS body bias voltage. The NMOS logic may be connected electrically to the PMOS logic and include a plurality of NMOS transistors whose operation points are determined according to the NMOS body bias voltage.

Abstract: A frequency divider (10A) includes an asynchronous finite state machine (AFSM) configured as a counter (20) having an input coupled to an input clock signal (CLK) for producing information representative of a plurality of phase signals (F0,F1,F2,F3) each of which is a divided-down representation of the input clock signal (CLK) and each of which is phase-shifted by a predetermined amount with respect to another of the phase signals (F0,F1,F2,F3). Programmable circuitry (22) operates in response to both dynamic divide ratio information (DIV_RATIO) and the information representative of the plurality of phase signals (F0,F1,F2,F3) so as to generate an output clock signal (CLKOUT) that is divided down according to both the dynamic divide ratio information and the information representative of the plurality of phase signals (F0,F1,F2,F3).

Abstract: Some embodiments of the invention provide a configurable integrated circuit (“IC”). The configurable IC includes a set of configurable logic circuits for configurably performing a set of functions. The configurable IC also includes a set of configurable routing circuits for routing signals to and from the configurable circuits. During several operational cycles of the configurable IC, a set of data registers are defined by the configurable routing circuits. These data registers may be used wherever a flip-flop can be used.

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: Circuits, methods, and apparatus that provide the improvement or recovery of a duty cycle of a clock signal. One embodiment of the present invention receives a clock signal that may have a degraded duty cycle. The frequency of the clock signal is divided by two. The frequency-divided signal is delayed in order to generate two signals that are phase shifted from one another by 90 degrees. These signals are then exclusive-ORed together to generate a recovered clock. A control loop is provided to adjust the phase shift between the signals to be approximately 90 degrees.

Abstract: A frequency divider includes a first latch and a second latch. The first latch is configured to receive a clock signal. The first latch is cross-coupled to the second latch. The second latch includes a circuit configured as a low-pass filter. The second latch further includes a differential pair of transistors. Each of the transistors include a drain, a source and a gate. The gates of the at least two transistors configured to receive a signal generated by the first latch. Additionally, the gates of the at least two other transistors are coupled to a control signal for determining a low-pass characteristic of the second latch.

Abstract: A direct injection-locked frequency divider circuit with inductive-coupling feedback architecture is proposed, which is designed for integration to a high-frequency circuit system with a high operating frequency such as 24 GHz (gigahertz), for providing a frequency-dividing function. The proposed frequency divider circuit comprises an injection-locked oscillator (ILO) circuit module and a pair of buffer-stage circuits, wherein the ILO circuit module further includes a signal-injection circuit, a cross-coupled switching circuit, and a variable-capacitance tuning circuit. The proposed circuit architecture is characterized by the circuit arrangement of a direct-injection architecture and an inductive-coupling feedback architecture by coupling the inductive elements of the buffer-stage circuits to the inductive elements of the variable-capacitance tuning circuit in the ILO circuit module.

Abstract: The invention relates to frequency adjustment of electronic signals. The method comprises the steps of providing an output signal of a frequency generator with a first frequency as input signal for a signal delay element providing an edge of said input signal of said signal delay element; delaying said input signal by adding a delay to each cycle of said input signal until the delayed output signal of the signal delay element is aligned to an edge of said input signal.

Abstract: A low voltage, low power, wideband quadrature divide-by-three frequency divider using a wideband low voltage, low power differential Muller C element with multiple inputs operates on quadrature input and quadrature output signals. This frequency divider can be used in frequency synthesizers and as quadrature local oscillator generator.

Abstract: A prescaling stage includes bistable circuit in turn including respective master and slave portions inserted between a first and a second voltage reference and feedback connected to each other. Each portion is provided with at least one differential stage supplied by the first voltage reference and connected, by a transistor stage, to the second voltage reference, as well as a differential pair of cross-coupled transistors, supplied by output terminals of the differential stage and connected, by the transistor stage, to the second voltage reference. Advantageously, each master and slave portion includes a degeneration capacitance inserted in correspondence with respective terminals of the transistors of the differential pair.

Abstract: A divider circuit comprises at least two clock edge controlled differential buffer store elements, each being clocked by complementary input clock signals, each comprising internal storage nodes which are pre-chargeable to a pre-charge potential, and each comprising a differential data input. The internal storage nodes of the buffer store elements are either pre-charged at the pre-charge potential or store a logic level, depending on the relevant input clock signals. The differential data inputs of one of the buffer store elements is connected to the internal storage nodes of the other buffer store element and pulsed signals can be tapped off at the internal differential storage node.

Abstract: A dual-injection locked frequency dividing circuit is proposed, which is designed for integration to a gigahertz signal processing circuit system for providing a frequency dividing function to gigahertz signals. The proposed circuit architecture is characterized by the provision of a dual-injection interface module on the input end for dividing the input signal into two parts for use as two injection signals, wherein the first injection signal is rendered in the form of a voltage signal and injected through a direct injection manner to the internal oscillation circuitry, while the second injection signal is rendered in the form of an electrical current and injected through a resonant circuit to the internal oscillation circuitry. This feature allow the proposed frequency dividing circuit to have broad frequency locking range and low power consumption.

Abstract: A circuit includes a logic circuit containing a first transistor and a second transistor which are connected in series to each other between a high power supply and a low power supply in such a manner that an emitter of one of the first and second transistors is connected to a collector of the other of the first and second transistors. The first transistor is positioned closer to the high power supply, and the second transistor is positioned closer to the low power supply. The logic circuit operates in accordance with voltages input into bases of the first and second transistors. The circuit further includes a current amplifying circuit containing a third transistor whose collector is connected to one of the high and low power supplies, whose emitter is connected to the other of the high and low power supplies, and whose base is connected to an output from the logic circuit.

Abstract: Methods and circuitry for distributing and synchronizing a divided clock signal in an electronic device are disclosed. In one aspect of an embodiment, a series of registers distributes the divided clock signal and the series of registers is clocked by a full-speed clock signal from which the divided clock signal is derived. In another aspect, the divided clock signal and the full-speed clock signal are distributed to IO circuitry of the electronic device. In yet another aspect, the divided clock signal is also distributed to circuitry in a core of the electronic device.

Abstract: A method for generating a clock signal and a device having clock generating capabilities, the device includes: (i) a first divider, adapted to receive an input clock signal and divide the input clock signal to provide a first clock signal; (ii) a second divider, adapted to receive an input clock signal and divide the input clock signal to provide a second clock signal; wherein the first clock signal is phase shifted in relation to the second clock signal by half an input clock cycle; wherein a delay period of the first divider substantially equals a delay period of the second divider over a large range of delay affecting parameter values; (iii) a reconstruction circuit, connected to the first and second divider circuits, adapted to receive the first and second clock signals and apply a logical operation on the first and second clock signals to provide a reconstructed clock signal; and (iv) a selection circuit, connected to the first divider, second divider and reconstruction circuit, adapted to output an outp

Abstract: A spread spectrum clock generator includes: a phase frequency detector, for generating a phase difference signal according to a frequency divided signal and a reference signal with a reference frequency; a charge pump, for receiving the phase difference signal and generating an output current according to the phase difference signal; a loop filter, for receiving the output current and converting the output current to a voltage-controlled signal; a voltage-controlled oscillator, for receiving the voltage-controlled signal and generating a plurality of voltage-controlled output signals, wherein the plurality of voltage-controlled signals have a specific phase difference and a same voltage-controlled frequency; a frequency dividing unit, for receiving the plurality of voltage-controlled output signal and generating the frequency divided signal; and a delta-sigma modulator, for controlling the frequency dividing unit to have an equivalent divided value of (N+b)S+(N?a)(P?S) through receiving the frequency divided

Abstract: A frequency divider including a first frequency-dividing unit, a second frequency-dividing unit, a selecting unit, and a counting unit is provided. The first frequency-dividing unit receives an input signal and divides a frequency of the input signal for outputting a plurality of phase signals, wherein phases of the phase signals are mutually different. The selecting unit is connected to the first frequency-dividing unit for selecting one of the phase signals according to a control signal, so as to output an inner signal. The second frequency-dividing unit is coupled to the selecting unit for dividing a frequency of the inner signal to serve an output signal. The counting unit is coupled to the selecting unit for counting the inner signal and outputting a counting result as the control signal. Therefore, the output signal with about 50% duty cycle can be provided.

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: Integrated circuit and process for aligning a first signal with a second signal. The integrated circuit includes a single latch, a switch control circuit coupled to an input of the single latch to align an edge of the first signal with an edge of the second signal, and a second switch control circuit coupled to the output of the single latch to produce a 50% duty cycle output.

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: A flip-flop, and a frequency divider and an RF circuit using the flip-flop. The frequency divider, which receives a first signal and generates a second signal by dividing a frequency of the first signal, including a plurality of flip-flops that each latch and output a signal based on the first signal; and at least one switch unit that is switched in response to a control signal to modify a signal transfer path between the plurality of the flip-flops, wherein a different number of flip-flops are activated in response to each first and second status of the control signal so that the frequency of the first signal is divided by different multiples.

Abstract: A dynamic frequency divider is proposed in which a double mixer is used for the dynamic frequency division. In one example the division is by N, where N?2 and a positive integer. The dynamic frequency divider further includes an input stage with level shift means, a filter filtering the output signal and providing a feedback signal to the double mixer. In one case, using just one double mixer significantly reduces the power consumption of a dynamic frequency divider and utilizes considerably less space, making it simpler, cheaper and smaller.

Abstract: A reference clock signal generation circuit for generating a reference clock signal for a charge-pump operation which raises or lowers a voltage includes a clock signal generation circuit which generates a reference clock signal having one of first to nth (n is an integer of two or more) frequencies, a wait time setting register in which a value corresponding to a wait time is set, and a frequency setting register in which a value corresponding to one of the first to nth frequencies is set. The clock signal generation circuit generates the reference clock signal having a predetermined frequency in a start period from start of the charge-pump operation to completion of the wait time, and generates the reference clock signal having a frequency corresponding to the value set in the frequency setting register in an operation period after the start period.

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: A circuit for deriving an output clock signal from an input clock signal, the output clock signal having a frequency which is 1/Nth of the frequency of the input clock signal, where N is an odd number. The circuit comprises a plurality of latches configured as a latch ring, the latches being arranged in successive pairs, each pair of latches comprising a first latch that switches on one of the rising or falling edge of the input clock signal, and a second latch that switches on the other of the rising or falling edge of the input clock signal. An RS flip flop is coupled to receive at one of its set and reset inputs an output from the latch ring that is switched on a rising edge, and at the other of the set and reset inputs an output from the latch ring that is switched on a falling edge. Said output clock signal is provided at an output of the RS flip flop.

Abstract: A flip-flop has a first latch and a second latch. The first latch has a first feedback circuit and a first selecting circuit which selects one of a first data input signal and an output signal of the first feedback circuit, based on the logic level of a first clock signal. The second latch has a second feedback circuit and a second selecting circuit which selects an output signal of the first latch and an output signal of the second feedback circuit based on the inverted logic level in case of the first latch. The first feedback circuit has a third selecting circuit which selects one of an output signal of the first latch and a second data input signal based on the logic level of a second clock signal, and outputs a signal selected by the third selecting circuit to the first selecting circuit.

Abstract: An integrated circuit includes a volatile memory, a central processing unit that normally operates on a first clock, and an input-output circuit that transfers data in synchronization with a second clock having a lower frequency than the first clock. The integrated circuit has a power-saving mode in which the volatile memory loses its data and the central processing unit stops operating. The power-saving mode is preceded and followed by transitional periods during which the central processing unit uses the input-output circuit to save data from the volatile memory to an external memory device and restore the data from the external memory device to the volatile memory. During these transitional periods, the central processing unit operates on the second clock to conserve power.

Abstract: Embodiments of the present invention synthesize a core frequency divider by adding a switching feedback shell and using multiple clock edges to trigger the frequency divider. Feedback logic is used to determine which edge will be used. Embodiments allow multiple recursive use, which boosts the overall speed resulting frequency divider circuit 2N times faster than the core frequency divider.

Abstract: The frequency divider includes the buffer 30, the function selector 31 and the inverter 32. The output of the function selector 31 is input to the buffer 30. The output of the buffer 30 is fed back to the function selector 31 by two paths. One path includes the inverter 32 and the other does not. The function selector 31 selects one of the paths in synchronous with input clock CK. At one timing the output of the buffer 30 is flipped by the inverter 32. At the next timing the output of the buffer 30 is held the same by the function selector 31 selecting the path not including the inverter 32.

Abstract: There is provided a true single phase logic clock divider that is configured to selectively divide a clock signal by increments of two, three, four, or six. Because the true single phase logic clock divider is based on true single phase logic instead of static logic, the true single phase logic clock divider is able to reliably divide clock signals that could not reliably be divided by clock dividers based on static logic gates. The true single phase logic clock divider is capable of reliably operating at frequencies of greater than or equal to two gigahertz.

Abstract: A frequency-division circuit comprises a pair of multi-state circuits (MSCA, MSCB). Each multi-state circuit can be switched throughout a cycle of states (SA(1), . . . , SA(N); SB(1), . . . , SB(N)). One multi-state circuit (MSCA) switches to a next state in response to a rising edge (Er) in an input signal (OS). The other multi-state circuit (MSCB) switches to a next state in response to a falling edge (Ef) in the input signal (OS). Each multi-state circuit (MSCA, MSCB) has at least one state (SA(1), SB(1)) in which the multi-state circuit inhibits the other multi-state circuit (MSCB, MSCA) so as to prevent the other multi-state circuit from switching to the next state.

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 high speed divider circuit is disclosed. The circuit contains a plurality of latches and buffers. The maximum input clock frequency of the divider circuit is increased over that implemented with only latches connected in a ring by feed forwarding the output of an early switching latch to the output of a later switching latch through buffers. The feed forward signal aids the later switching latch to complete the next state transition. By choosing the appropriate ratio of the buffer tail current to the latch tail current, the divider circuit can be made into a dynamic divider circuit.

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: An integrated circuit device which internally generates a plurality of drowsy clock signals having different phases is provided. The integrated circuit device includes a phase synchronizer configured to output a plurality of clock signals having different phases in response to an external clock signal and a drowsy clock signal output unit configured to divide frequencies of the plurality of clock signals by a first factor, align the frequency-divided clock signals so that each consecutive clock signal has a constant phase difference relative to a phase difference of a preceding clock signal, and output the drowsy clock signals having lower frequencies and different phases. The integrated circuit device also includes a feedback unit configured to divide frequency of a clock signal with a phase angle of 0 output by the phase synchronizer by the first factor and output the frequency-divided clock signal having a phase angle of 0 degrees to an input port of the phase synchronizer.

Abstract: A dual-injection locked frequency dividing circuit is proposed, which is designed for integration to a gigahertz signal processing circuit system for providing a frequency dividing function to gigahertz signals. The proposed circuit architecture is characterized by the provision of a dual-injection interface module on the input end for dividing the input signal into two parts for use as two injection signals, wherein the first injection signal is rendered in the form of a voltage signal and injected through a direct injection manner to the internal oscillation circuitry, while the second injection signal is rendered in the form of an electrical current and injected through a resonant circuit to the internal oscillation circuitry. This feature allow the proposed frequency dividing circuit to have broad frequency locking range and low power consumption.

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.

Abstract: Generating an output signal having a frequency of 1/(M+F) of the frequency of the input signal, wherein M represents an integer and F represents a non-zero fraction. Assuming F equals (Q/R) in one embodiment, wherein Q and R are integers, R intermediate signals phase shifted by equal degree (relative to the one with closest phase shift) in one clock period of the input signal are generated. A selection circuit may select one of the intermediate signals in one clock cycle, select the successive signals with increasing phase shift in Q clock cycles, and leave the intermediate signal with the same shift as in the previous clock cycle in the remaining ones of the M clock cycles. A counter counts a change of state in the output of the selection circuit, and generates a pulse representing an edge of the output signal at the time instance when counter counts M.

Abstract: A distributed charge pump system uses a delay element and frequency dividers to generate out of phase pump clock signals that drive different charge pumps, to offset peak current clock edges for each charge pump and thereby reduce overall peak power. Clock signal division and phase offset may be extended to multiple levels for further smoothing of the pump clock signal transitions. A dual frequency divider may be used which receives the clock signal and its complement, and generates two divided signals that are 90° out of phase. In an illustrative embodiment the clock generator comprises a variable-frequency clock source, and a voltage regulator senses an output voltage of the charge pumps, generates a reference voltage based on a currently selected frequency of the variable-frequency clock source, and temporarily disables the charge pumps (by turning off local pump clocks) when the output voltage is greater than the reference voltage.

Abstract: A divider is provided. The divider includes a first flip-flop, a flip-flop array, a first NOT gate, a second NOT gate, and a circuit. The first flip-flop can be triggered by a frequency signal. The first NOT gate is coupled between a positive output terminal of the last second flip-flop and the first flip-flop. The second NOT gate is coupled between the positive output terminal of the last second flip-flop and the circuit. The first NOT gate and the second NOT gate are controlled by the mode control signal for enabling. If N is an odd number, the circuit includes a wire, and if N is an even number, the circuit includes a third NOT gate.

Abstract: An injection-locked frequency divider (ILFD) can go beyond simple frequency division by an even number. In one embodiment, another differential pair of transistors is added to convert the injection signal into differential currents, which are mixed in the original transistor pair such as that of the conventional ILFD shown above. In another, a double-balanced ILFD structure includes multiple ILFD's which are independently tunable to allow phase differences other than quadrature.

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: A multi-phase frequency divider comprises dynamic inverters connected in a ring and the intermediate nodes around the ring are stabilized with cross-coupled latches. Clock input pulses enable each dynamic inverter's output and will force a corresponding change-of-state in the cross-coupled latches. The multi-phase output is presented in parallel on all the latches.

Abstract: A method for dividing a signal having a first frequency by a divide ratio includes selecting, based on the divide ratio, a first pulse width of at least one signal having a second frequency and being generated by at least a corresponding one of a plurality of pulse-width control circuits responsive to at least one signal having a second pulse width. The method includes selecting at least one of the plurality of pulse-width control circuits to be powered-on to generate the at least one signal. The at least one of the plurality of pulse-width control circuits includes a first pulse-width control circuit to generate a first signal having the first pulse-width, second frequency, and first phase. The first signal corresponds to a select circuit output signal having a first phase. The method includes selecting at least one other of the plurality of pulse-width control circuits to be powered-off.

Abstract: A multiphase divider comprises several differential latches connected in a ring. The number of latches in the ring is equal to the number of phases produced and the divisor applied to the input clock. The differential Q-outputs of one latch stage are connected to the corresponding differential D-inputs of the next latch stage. For even numbers of latch stages, the differential clock inputs of each are connected together and alternately to the divider clock input and its complement. The last differential Q-output is returned and cross-connected to the differential D-inputs of the first latch stage. For odd numbers of latch stages, the differential clock inputs of each are respectively connected in parallel to the divider clock input and its complement. The last differential Q-output is returned and straight-connected to the differential D-inputs of the first latch stage.

Abstract: The dual-modulus prescaler circuit (1) is devised to operate at a very high frequency. This circuit includes an assembly formed of two dynamic D-type flip flops (12, 13), and two NAND logic gates (15, 16) arranged in negative feedback between the two flip flops. The two flip flops are clocked by an input clock signal (CK) to supply a divided output signal (OUT) whose frequency matches the input clock frequency divided by 2 or by 3 as a function of a division mode selection signal (divb) applied to the input of the first NAND logic gate (15). One non-inverted output of the second flip flop is connected to one input of the first flip flop (12). The first dynamic flip flop includes three active branches and supplies a single inverted output signal. A third flip flop (14) with three active branches receives an inverted mode selection signal (div) at input in order to supply the mode selection signal to the inverted output thereof, clocked by the non-inverted output signal of the second flip flop.

Abstract: The keypad interface element of this invention uses a relaxation oscillator and a digital keypad processor having a counter/timer to decode specific keys. The RC portion of the relaxation oscillator includes a resistance ladder and a set of momentary on pushbutton switches disposed change resistance dependent upon which key is pressed. This causes the relaxation oscillator to produce an output signal having a corresponding frequency. The counter/timer of the digital keypad processor produces a count corresponding to the oscillator frequency. The digital keypad processor latches and holds a binary number specifically identifying the depressed key. A state machine in the digital keypad processor provides transient-free, noise immune keypad decoding.