A local oscillator generator (LO generator) may be configured to transmit an LO signal to a mixer. The LO generator may include an input buffer configured to generate a first internal oscillator signal based on the input oscillator signal. The LO generator may include a frequency dividing circuit configured to generate a second internal oscillator signal based on dividing a frequency of the first internal oscillator signal. The LO generator may include an output buffer configured to generate the LO signal based on the second internal oscillator signal. The input buffer and the frequency dividing circuit may each be configured to receive a power voltage independently of the output buffer.

A circuit includes an RF oscillator coupled in a phase-locked loop. The phase-locked loop is configured to receive a digital input signal, which is a sequence of digital words, and to generate a feedback signal for the RF oscillator based on the digital input signal. The circuit further includes a digital-to-analog conversion unit that includes a pre-processing stage configured to pre-process the sequence of digital words and a digital-to-analog-converter configured to convert the pre-processed sequence of digital words into the analog output signal. The circuit includes circuitry configured to combine the analog output signal and the feedback signal to generate a control signal for the RF oscillator. The pre-processing stage includes a word-length adaption unit configured to reduce the word-lengths of the digital words and a sigma-delta modulator coupled to the word-length adaption unit downstream thereof and configured to modulate the sequence of digital words having reduced word-lengths.

Some embodiments include apparatuses having a first path in a phase locked loop, the first path including a phase frequency detector to receive a first signal having a first frequency and a first node to provide a voltage; an oscillator coupled to a second node and the first node to provide a second signal having a second frequency at the second node; a second path including a frequency divider coupled to the second node and the phase frequency detector; and a circuit to generate digital information having a value based on a value of the voltage at the second node.

A phase-locked loop according to the present disclosure includes a reference-phase generation circuit that sequentially generates a reference phase value, and an oscillating circuit that generates a first clock on a basis of a difference between the reference phase value and a feedback phase value. The phase-locked loop further includes a signal generation circuit that generates, on a basis of the first clock, a plurality of second clocks varying in phase, and generates a third clock by switching the plurality of second clocks a plurality of times in each of cycle periods each corresponding to one cycle of the reference clock. The phase-locked loop further includes a phase detection circuit that determines a phase value of the third clock and outputs the determined phase value as the feedback phase value.

A phase control oscillator includes a voltage control oscillator, a phase comparator, a loop filter, and a storage unit. The loop filter is configured such that if the phase control oscillator starts operating, the loop filter outputs a control voltage based on phase difference information to the voltage control oscillator. The storage unit stores deviation information indicative of a deviation between a phase difference when the loop filter outputs the control voltage in the case where the phase control oscillator starts operating and the phase difference indicated by the phase difference information. After the loop filter outputs the control voltage in response to the phase control oscillator starting operating, the loop filter outputs the control voltage based on the phase difference information output from the phase comparator and the deviation information stored in the storage unit, to the voltage control oscillator.

A PFD outputs a detection signal based on a phase difference or a frequency difference between a reference signal and a feedback signal, a charge pump circuit outputs a pulse signal based on the detection signal, and a loop filter outputs a control voltage based on the pulse signal. A VCO includes a ring oscillator where a plurality of delay element units, which include a plurality of delay elements (for example, inverter circuits) connected in parallel, are connected in series in a ring, controls the frequency of the output signal of the ring oscillator based on the control voltage, and controls the phase of the output signal of the ring oscillator by controlling the active number of delay elements, out of the plurality of delay elements, based on the detection signal. A frequency divider circuit generates and outputs a feedback signal by dividing the frequency of the output signal.

The present disclosure relates to a deadlock recovery unit for applying a one-shot pulse signal to restart a Voltage Controlled Oscillator (VCO) when the output clock signal of the VCO remains in a high state or a low state. The deadlock recovery unit includes a VCO clock monitoring unit for monitoring a clock signal of a voltage control oscillator; a pulse signal generating unit for outputting a one-shot pulse signal to reset the VCO when a clock signal is not counted; and a control signal generating unit for generating a VCO counter enable signal applied to the VCO clock monitoring unit and a detector clock signal applied to the pulse signal generating unit by using an externally supplied reference clock signal.

Method and apparatus for determining a clock frequency for an electronic processor are provided. One embodiment provides a clock generator for determining a clock frequency for an electronic processor and providing a clock signal to the electronic processor. The clock generator includes a crystal oscillator producing a reference signal and a phase locked loop receiving the reference signal and configured to generate the clock signal based on the reference signal. The clock generator also includes a tuning logic controller electrically coupled to the phase locked loop. The tuning logic controller is configured to program the phase locked loop to a first frequency and determine an integrated circuit process corner of the electronic processor. The tuning logic controller is also configured to determine a second frequency based on the integrated circuit process corner and program the phase locked loop to the second frequency.

The invention provides a power system for monitoring a working environment of a monitored circuit and adjusting a working voltage of the monitored circuit includes: a power circuit, a voltage-controlled oscillator and a counter. The power circuit is configured to output the working voltage to the monitored circuit through a power supply path. The voltage-controlled oscillator is disposed in or around the monitored circuit and is electrically connected to the power supply path and a ground path to which the monitored circuit is electrically connected, and is configured to output an oscillation frequency in accordance with a signal variation on the power supply path and the ground path. The counter is electrically connected to the voltage-controlled oscillator and is configured to generate a counting number signal in accordance with the oscillation frequency and a synchronizing signal, thereby adjusting the working voltage outputted to the monitored circuit.

Some embodiments include apparatuses and methods of operating such apparatuses. One of the apparatuses includes a first circuit included in a phase-locked loop (PLL) to receive an input clock signal and a feedback clock signal, and to generate an output clock signal; a second circuit included in the PLL to generate the feedback clock signal from the output clock signal; and a third circuit to prevent the output clock signal from toggling during a portion of a time interval when the PLL performs an operation of aligning phases of the input clock signal and feedback clock signal.