An apparatus is disclosed that implements frequency synthesis with accelerated locking. In an example aspect, the apparatus includes an oscillating signal source, a modulus compensator, and a frequency generator. The oscillating signal source is configured to provide a reference signal having a reference frequency. The modulus compensator is coupled to the oscillating signal source and is configured to receive the reference signal. The modulus compensator is configured to produce a compensated modulus value based on the reference frequency, a fixed oscillator frequency of a fixed-frequency oscillator signal, and a modulus value. The frequency generator is coupled to the oscillating signal source and the modulus compensator and is configured to receive the compensated modulus value. The frequency generator is configured to generate an output signal having an output frequency that is based on the reference frequency and the compensated modulus value.

An apparatus is disclosed that implements frequency synthesis with accelerated locking. In an example aspect, the apparatus includes an oscillating signal source, a modulus compensator, and a frequency generator. The oscillating signal source is configured to provide a reference signal having a reference frequency. The modulus compensator is coupled to the oscillating signal source and is configured to receive the reference signal. The modulus compensator is configured to produce a compensated modulus value based on the reference frequency, a fixed oscillator frequency of a fixed-frequency oscillator signal, and a modulus value. The frequency generator is coupled to the oscillating signal source and the modulus compensator and is configured to receive the compensated modulus value. The frequency generator is configured to generate an output signal having an output frequency that is based on the reference frequency and the compensated modulus value.

A sub-sampler phase locked loop (SSPLL) system having a frequency locking loop (FLL) and a phase locked loop (PLL) is disclosed. The FLL is configured to detect frequency variations between a phase locked loop (PLL) output signal and a reference frequency and automatically generate a pulsed correction signal upon the detected frequency variations and apply the pulsed correction signal to a voltage controlled oscillator (VCO) control voltage. The PLL is configured to generate the PLL output signal based on the VCO control voltage.

Various embodiments a PLL-based clock unit is disclosed. An exemplary clock unit includes a PLL, a low-jitter XO to provide a low-jitter input clock and a low-cost TCXO to provide a low-temperature-drift clock. The clock unit additionally includes a holdover module coupled to the PLL and configured to receive the low-jitter input clock and a reference input clock; record a relationship between the low-jitter input clock and the reference input clock during a normal operation mode; and output the recorded relationship to the PLL as a control signal during a holdover operation mode when the reference input clock is unavailable. This clock unit additionally includes a statistical module to compute a relationship between the low-jitter input clock and the low-temperature-drift clock; and a control module to dynamically adjust the output of the holdover module based on the determined relationship so that the output clock of the clock unit maintains both low-jitter and low-temperature-drift characteristics.

A capacitor bank has a capacitance value that is discontinuous and has an extremely narrow variable range. Thus, in a case of obtaining a wide variable range of the capacitance value, a large number of capacitors are connected in parallel and used while being switched by switches. The present technology achieves at least one of: allowing the capacitance value of a variable capacitance circuit to be varied continuously by electrical control without increasing the parasitic capacitance; and decreasing the current consumption of an oscillator circuit using the variable capacitance circuit as compared to a conventional case. The variable capacitance circuit includes: a transconductance circuit that includes a MOS transistor; an inductor that is connected in parallel to the transconductance circuit; and a Gm control circuit that varies a transconductance of the MOS transistor.

Various embodiments a PLL-based clock unit is disclosed. An exemplary clock unit includes a PLL, a low-jitter XO to provide a low-jitter input clock and a low-cost TCXO to provide a low-temperature-drift clock. The clock unit additionally includes a holdover module coupled to the PLL and configured to receive the low-jitter input clock and a reference input clock; record a relationship between the low-jitter input clock and the reference input clock during a normal operation mode; and output the recorded relationship to the PLL as a control signal during a holdover operation mode when the reference input clock is unavailable. This clock unit additionally includes a statistical module to compute a relationship between the low-jitter input clock and the low-temperature-drift clock; and a control module to dynamically adjust the output of the holdover module based on the determined relationship so that the output clock of the clock unit maintains both low-jitter and low-temperature-drift characteristics.

A phase-locked loop circuit calibration method for a memory storage device including a rewritable non-volatile memory module is provided according to an exemplary embodiment of the disclosure. The method includes: receiving a first signal from a host system; generating a jitter signal by the memory storage device; generating a second signal according to the first signal and the jitter signal; performing a phase-lock operation on the second signal to generate a third signal by a phase-locked loop circuit; and detecting the third signal to calibrate an electronic parameter of the phase-locked loop circuit.

A PLL circuit includes a phase comparator, first and second charge pumps, a filter generating a first control voltage from a current of the first charge pump, a comparator comparing a voltage of a first node with a reference voltage, a switch section outputting the reference voltage to the first node and outputting a current of the second charge pump to a second node in a high-speed lock mode, and outputting the current of the second charge pump to the first node and outputting a result from the comparator to the second node in a normal lock mode, a second filter generating a second control voltage by integrating a current of the first node, a third filter generating a third control voltage by integrating a current of the second node, and a voltage controlled oscillator generating a clock signal of a frequency corresponding to the first to third control voltages.

A PLL has a tunable resonator including an inductance and variable capacitance coupled between first and second nodes, and capacitances coupleable between the nodes. A control node is coupled to the variable capacitance and receives a control signal for tuning the resonator. A biasing circuit biases the resonator to generate an output. A PFD circuit senses timing offset of the output with respect to a reference and asserts first or second digital signals dependent on the sign of the timing offset. A charge pump generates the control signal based on the first and second digital signals. A timer asserts a timing signal in response to a pulse sensed in a reset signal and de-asserts the timing signal after a time interval. A calibrator couples selected capacitances between the first and second nodes as a function of the second digital signal, in response to assertion of the timing signal.

A phase-locked loop circuit calibration method for a memory storage device including a rewritable non-volatile memory module is provided according to an exemplary embodiment of the disclosure. The method includes: receiving a first signal from a host system; generating a jitter signal by the memory storage device; generating a second signal according to the first signal and the jitter signal; performing a phase-lock operation on the second signal to generate a third signal by a phase-locked loop circuit; and detecting the third signal to calibrate an electronic parameter of the phase-locked loop circuit.