Structure and method for realizing quick locking of phase-locked loop

Abstract

The invention discloses a structure for realizing quick locking of a phase-locked loop. The structure includes a phase-locked loop which is formed by successive connection of a phase comparator, a loop filter, a control switch, a voltage controlled oscillator, and a digital frequency divider, and a control module which is connected with the voltage controlled oscillator, the digital frequency divider and the control switch and can adjust and control the voltage controlled oscillator, the digital frequency divider and the control switch. The structure also includes a main oscillator which is connected with the phase comparator, a frequency selector which is connected with the digital frequency divider and the control module, and a reset circuit which is connected with the control module. The invention also provides a method for realizing quick locking of a phase-locked loop. The method can automatically correct the frequency of the phase-locked loop when a switch is not required to be disconnected, so that the locking time is reduced and the aim for quick locking is realized. When changing of the working frequency exceeds a quick capture band, the required frequency can be captured without requirement for performing the loop opening correction process, so that quick capture can be realized.

Description

technical field [0001] The invention relates to a component of communication electronic equipment, in particular to a phase-locked loop. Background technique [0002] With the development of society, electronic devices are becoming more and more popular. All electronic devices with communication functions have a circuit structure of a phase-locked loop. The phase-locked loop in the electronic device can provide a clock signal or other reference signals to ensure the normal operation of the device. Generally speaking, a voltage-controlled oscillator is included in the phase-locked loop circuit, so the phase-locked loop can provide an adjustable frequency for the system. By changing the frequency division ratio of the digital frequency divider, the frequency of the phase-locked loop can be adjusted. The phase-locked loop using automatic frequency correction technology can only correct the frequency of the voltage-controlled oscillator when the loop is open, so when changing ...

AI Technical Summary

Problems solved by technology

The existing methods to achieve fast locking of the phase-locked loop, whether it is designing a wide-band voltage-controlled oscillator or designing a new automatic frequency correction circuit, will make the design more complicated and increase the difficulty of circuit design

Furthermore, due to the increased difficulty of circuit design, no experienced engineer can guarantee the quality of tape-outs, which will undoubtedly increase the number of tape-outs, thereby increasing production costs

At the same time, the increase of circuit complexity will also bring certain instability.

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