Phase-locked loop and calibration method of voltage-controlled oscillator of phase-locked loop

Abstract

The technical scheme of the invention provides a phase-locked loop and a calibration method of a voltage-controlled oscillator of the phase-locked loop. The phase-locked loop comprises: a phase frequency detector, a charge pump, a loop filter, a voltage-controlled oscillator, a frequency divider and a calibration circuit; the calibration circuit is used for acquiring the frequency of an output signal of the voltage-controlled oscillator, calibrating the frequency of the output signal of the voltage-controlled oscillator according to the expected frequency, acquiring a frequency control parameter of the voltage-controlled oscillator under the current signal frequency, acquiring an amplitude control parameter and a gain control parameter according to the frequency control parameter, and keeping the amplitude and the gain of an output signal of the voltage-controlled oscillator constant according to the amplitude control parameter and the gain control parameter. The phase-locked loop provided by the invention can meet the frequency requirement of multiple protocols on the phase-locked loop, and can adaptively search and stably work at an appropriate frequency, so that the circuit hasthe optimal performance, and meanwhile, the problem that the amplitude of a signal output by a voltage-controlled oscillator is inconstant when the phase-locked loop works in a large frequency range is solved.

Description

technical field [0001] The invention relates to the technical field of phase-locked loop circuits, in particular to a calibration method for a phase-locked loop and a voltage-controlled oscillator thereof. Background technique [0002] Phase-locked loop is an indispensable part of high-speed communication system. As a frequency synthesizer, phase-locked loop provides a suitable clock frequency for high-speed communication system. The phase-locked loop based on the voltage-controlled oscillator of the inductor-capacitor resonant cavity has a very superior Phase noise characteristics are widely used in high-speed communication systems. The inherent inductance-capacitance resonator of the voltage-controlled oscillator based on the inductance-capacitance resonator has a high quality factor, so its operating frequency range is relatively narrow. Moreover, when the phase-locked loop is working, the oscillating voltage signal of the inductance-capacitance resonator will increase ...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a calibration method of a phase-locked loop and its voltage-controlled oscillator, to solve the problem of unstable signal output by the voltage-controlled oscillator in the prior art

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