In one embodiment, the voltage droop monitoring circuit includes a ring oscillator circuit block configured to generate a plurality of oscillation signals and configured to output a selected oscillation signal from one of the plurality of oscillation signals based on a first control signal. The first control signal is based on a power supply voltage of a functional circuit block. The voltage droop monitoring circuit further includes a counter configured to generate a count value based on the selected oscillation signal, and a droop detector configured detect droop in the power supply voltage of the functional circuit block based on the count value and at least one threshold value.

A delay line includes first to n-th delay cells and a dummy delay cell, ‘n’ being an integer greater than or equal to 3. The first to n-th delay cells sequentially delay an input signal to respectively generate first to n-th output signals. The dummy delay cell delays the n-th output signal based on a delay control voltage to generate a dummy output signal. A delay amount of each of the first to (n−1)-th delay cells is adjusted on a basis of the delay control voltage and the output signal of the delay cell of a next stage of the corresponding delay cell, and a delay amount of the n-th delay cell is adjusted on a basis of the delay control voltage and the dummy output signal.

The present invention includes a voltage controlled oscillator circuit and a phase-locked loop device. The voltage controlled oscillator circuit comprises: a voltage-to-current conversion module, used for converting a control voltage of a voltage controlled oscillator into a control current as a linear function of the control voltage; and a current controlled oscillation module, used for outputting a low-amplitude oscillation signal based on the control current, so as to reduce power consumption. Further provided in the present invention is a phase-locked loop device comprising the voltage controlled oscillator circuit. According to the voltage controlled oscillator circuit, design parameters of low power consumption and high linearity may be achieved, thereby making a gain Kvco of the voltage controlled oscillator relatively stable, and it may be ensured that the voltage controlled oscillator and the phase-locked loop comprising the same have relatively excellent device performance.

A phase locked loop circuit is disclosed. The phase locked loop circuit includes a ring oscillator. The phase locked loop circuit also includes a digital path including a digital phase detector. The phase locked loop circuit further includes an analog path including a linear phase detector. Additionally, the phase locked loop circuit includes a feedback path connecting an output of the ring oscillator to an input of the digital path and an input of the analog path. The digital path and the analog path are parallel paths. The digital path provides a digital tuning signal the ring oscillator that digitally controls a frequency of the ring oscillator. The analog path provides an analog tuning signal the ring oscillator that continuously controls the frequency of the ring oscillator.

An apparatus implements a multiplying delay-locked loop (MDLL) including a sampler to be calibrated. In an example aspect, an apparatus includes an MDLL and a sampler calibrator. The MDLL includes a locked-loop feedforward path with a sampler, a control output, a feedback input, and a reference input coupled to a reference signal source. The MDLL also includes a VCO, a multiplexer, and a divider. The VCO includes a VCO input, a VCO output, and a control input coupled to the control output. The multiplexer includes a first input coupled to the reference signal source, a second input coupled to the VCO output, and an output coupled to the VCO input. The divider is coupled between the VCO output and the feedback input. The sampler calibrator includes a first input coupled to the reference signal source, a second input coupled to the VCO output, and an output coupled to the sampler.

In a time-to-digital converter, a digital signal outputted by a phase information generator is inputted to each of the D terminals of first through Nth (N is a natural number equal to or greater than 2) D-type flip-flop circuits in a first flip-flop group, each of the D terminals is connected to one end of a first delay element, the C terminal of the first D-type flip-flop circuit is connected to another end of the first delay element, the other end of the first delay element is connected to an input terminal, and, when N, the number of flip-flop circuits in the first flip-flop group, is equal to or greater than 3, for each J a natural number from 2 to N−1, C terminal of the (J+1)th D-type flip-flop circuit is connected to one end of the Jth delay element and one end of the (J−1)th delay element is connected to the other end of the Jth delay element.

The present invention includes a voltage controlled oscillator circuit and a phase-locked loop device. The voltage controlled oscillator circuit comprises: a voltage-to-current conversion module, used for converting a control voltage of a voltage controlled oscillator into a control current as a linear function of the control voltage; and a current controlled oscillation module, used for outputting a low-amplitude oscillation signal based on the control current, so as to reduce power consumption. Further provided in the present invention is a phase-locked loop device comprising the voltage controlled oscillator circuit. According to the voltage controlled oscillator circuit, design parameters of low power consumption and high linearity may be achieved, thereby making a gain Kvco of the voltage controlled oscillator relatively stable, and it may be ensured that the voltage controlled oscillator and the phase-locked loop comprising the same have relatively excellent device performance.

The present disclosure includes a frequency divider circuit that includes a superharmonically injection-locked ring oscillator, injection circuitry, and various switches. The input can include a collection of signal components at different phases that are all at the same, but changeable, frequency. The divider's division ratio can be changed during the divider's operation by, for example, utilizing one or more switches to change: the number of stages in the ring oscillator, and/or which stage(s) of the ring oscillator are injected into by which input signal components.

In a time-to-digital converter, a digital signal outputted by a phase information generator is inputted to each of the D terminals of first through Nth (N is a natural number equal to or greater than 2) D-type flip-flop circuits in a first flip-flop group, each of the D terminals is connected to one end of a first delay element, the C terminal of the first D-type flip-flop circuit is connected to another end of the first delay element, the other end of the first delay element is connected to an input terminal, and, when N, the number of flip-flop circuits in the first flip-flop group, is equal to or greater than 3, for each J a natural number from 2 to N−1, C terminal of the (J+1)th D-type flip-flop circuit is connected to one end of the Jth delay element and one end of the (J−1)th delay element is connected to the other end of the Jth delay element.

An apparatus implements a multiplying delay-locked loop (MDLL) including a sampler to be calibrated. In an example aspect, an apparatus includes an MDLL and a sampler calibrator. The MDLL includes a locked-loop feedforward path with a sampler, a control output, a feedback input, and a reference input coupled to a reference signal source. The MDLL also includes a VCO, a multiplexer, and a divider. The VCO includes a VCO input, a VCO output, and a control input coupled to the control output. The multiplexer includes a first input coupled to the reference signal source, a second input coupled to the VCO output, and an output coupled to the VCO input. The divider is coupled between the VCO output and the feedback input. The sampler calibrator includes a first input coupled to the reference signal source, a second input coupled to the VCO output, and an output coupled to the sampler.