Phase-locked loop device with loop bandwidth correction function and method thereof

Abstract

The invention discloses a phase-locked loop device with a loop bandwidth calibration function and a loop bandwidth calibration method. The loop bandwidth calibration method comprises the steps of generating an output signal by use of a phase-locked loop circuit according to a reference signal and a feedback signal, modulating a feedback coefficient to make the feedback signal and the reference signal unlocked, detecting two effective crossover points of the phase difference between the reference signal and the feedback signal, calculating the oscillation frequency according to the two effective crossover points, and setting control parameters of the phase-locked loop circuit according to the oscillation frequency. Thus, the feedback signal is correlated with the output signal, and the feedback coefficient exists between the feedback signal and the output signal.

Description

technical field [0001] The invention relates to a correction technology of loop bandwidth, in particular to a phase-locked loop device and method thereof with a loop bandwidth correction function. Background technique [0002] Phase Lock Loop (Phase Lock Loop; PLL) is a typical technology used to synthesize frequency signals. For frequency tuning of radio waves or clock control of digital products, phase-locked loops can be used to design frequency control loops. [0003] Generally speaking, in a phase-locked loop, there is a specific phase relationship between the input and output periodic signals. The circuit structure of the phase-locked loop mainly includes a phase frequency detector (phase frequency detector; PFD), a charge pump (chargepump), a loop filter (loop filter), a voltage controlled oscillator (voltage controlled oscillator; VCO) and a feedback unit. [0004] The general operation of a phase locked loop is as follows. The beginning is the frequency acquisiti...

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Problems solved by technology

However, the set loop bandwidth is usually affected by factors such as semiconductor process changes, external component changes, power supply changes, and environmental conditions, resulting in loop bandwidth drift

[0006] Nowadays, many correction techniques for loop bandwidth have been developed, but there are still problems such as the correction method cannot respond to the results of each loop operation, and the structure of the applied phase-locked loop is limited.

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