A DTC circuit, includes: a DAC connected to a first node; a first switch connected between a first power source and a second node, and to provide a charge current to the second node according to a first switching signal; and a second switch connected between the first node and the second node, and to electrically connect the DAC to the second node according to a second switching signal. The DAC is to be charged to generate a voltage ramp corresponding to the charge current during a first DTC operational phase when the first and second switching signals have an active level to turn on the first and second switches, and to generate an input control word dependent voltage according to an input control word during a second DTC operational phase when the first and second switching signals have an inactive level to turn off the first and second switches.

A flash analog-to-digital converter (ADC) receives an input control signal and performs coarse tuning of a frequency of an output signal, produced between first and second nodes having an inductance coupled therebetween. The flash ADC quantizes an operating frequency range for the output signal produced between the first and second nodes as M.Math.?f, where M is an integer from 0 to N?1, where N is a number of intervals into which a frequency range for the output signal is divided, and where ?f is a resulting frequency step produced by the quantizing. The value of M is generated based upon the input control signal and a word controlling switches of a plurality of switched capacitance circuits associated with the first and second nodes to close ones of those switches associated with the control word to coarsely tune the frequency of the output signal.

A flash analog-to-digital converter (ADC) receives an input control signal and performs coarse tuning of a frequency of an output signal, produced between first and second nodes having an inductance coupled therebetween. The flash ADC quantizes an operating frequency range for the output signal produced between the first and second nodes as M.Math.?f, where M is an integer from 0 to N?1, where N is a number of intervals into which a frequency range for the output signal is divided, and where ?f is a resulting frequency step produced by the quantizing. The value of M is generated based upon the input control signal and a word controlling switches of a plurality of switched capacitance circuits associated with the first and second nodes to close ones of those switches associated with the control word to coarsely tune the frequency of the output signal.

There is disclosed configurable frequency-divider circuitry for generating a target signal of a frequency Fr/Di based on a reference signal of a frequency Fr, where Di is an integer divider ratio, the frequency-divider circuitry comprising: N divider stages organised into a ring, each stage configured to receive an input signal and generate an output signal, with the output signal of each successive stage in the ring being the input signal of the next stage in the ring, wherein: the ring of stages is controlled by the reference signal so that the output signals are governed by the reference signal; the target signal is one of the output signals or a signal derived therefrom; and at least one of the stages is a configurable stage, whose mode of operation is configurable based on a configuration signal to configure the value of Di.

An injection locked frequency divider includes a mixer circuit and a filter circuit. The mixer circuit includes two mixer units and two inductors. The mixer units mix a differential input voltage signal with a reference signal to output a differential current signal. The inductors cooperatively receive the differential current signal from the mixer units. The filter circuit is connected to the inductors, and filters the differential current signal to output a filtered differential voltage signal.

An injection locked frequency divider includes a mixer circuit and a filter circuit. The mixer circuit includes two mixer units and two inductors. The mixer units mix a differential input voltage signal with a reference signal to output a differential current signal. The inductors cooperatively receive the differential current signal from the mixer units. The filter circuit is connected to the inductors, and filters the differential current signal to output a filtered differential voltage signal.

An apparatus includes a plurality of latches and a plurality of logic gates. Each latch may be setable and resettable. The logic gates may be connected to the latches to form a multi-modulus divider that generates an output clock signal by dividing an input clock signal in response to a command signal. Each latch may be commanded into a corresponding initial state while the command signal is in an initialization state. Each latch is generally free to change states while the command signal is in a run state. A modulus division operation of the multi-modulus divider may start upon an initial edge of the input clock signal after the command signal changes from the initialization state to the run state.

An apparatus includes a plurality of latches and a plurality of logic gates. Each latch may be setable and resettable. The logic gates may be connected to the latches to form a multi-modulus divider that generates an output clock signal by dividing an input clock signal in response to a command signal. Each latch may be commanded into a corresponding initial state while the command signal is in an initialization state. Each latch is generally free to change states while the command signal is in a run state. A modulus division operation of the multi-modulus divider may start upon an initial edge of the input clock signal after the command signal changes from the initialization state to the run state.

A circuit includes a phase-frequency-detector generating first and second digital control signals indicative of phase differences between an input reference-signal and an output-signal, a charge-pump generating a control-signal based upon the first and second digital control signals, and an oscillator-circuit. The oscillator-circuit includes an active core coupled between first and second nodes, with a tunable resonant circuit a set of capacitances selectively connected between the first and second nodes, wherein a tap between the first and second variable capacitances receives the control-signal for tuning the tunable resonant circuit. A timer-circuit generates a timing-signal based upon the input reference-signal and a reset-signal. A calibration-circuit controls which capacitances of the set of capacitances are connected between the first and second nodes, in response to the timing-signal and a comparison between a threshold and a voltage-signal that is based upon auxiliary pulsed currents generated based upon the first and second digital control signals.

A circuit includes a phase-frequency-detector generating first and second digital control signals indicative of phase differences between an input reference-signal and an output-signal, a charge-pump generating a control-signal based upon the first and second digital control signals, and an oscillator-circuit. The oscillator-circuit includes an active core coupled between first and second nodes, with a tunable resonant circuit a set of capacitances selectively connected between the first and second nodes, wherein a tap between the first and second variable capacitances receives the control-signal for tuning the tunable resonant circuit. A timer-circuit generates a timing-signal based upon the input reference-signal and a reset-signal. A calibration-circuit controls which capacitances of the set of capacitances are connected between the first and second nodes, in response to the timing-signal and a comparison between a threshold and a voltage-signal that is based upon auxiliary pulsed currents generated based upon the first and second digital control signals.