Phase-locked acceleration circuit based on level width extraction and phase-locked loop system

Abstract

The invention discloses a phase-locked acceleration circuit based on level width extraction and a phase-locked loop system. The phase-locked acceleration circuit comprises a level extraction control circuit and a current injection switch module. The control output end of the level extraction control circuit is connected with the current injection control end of the current injection switch module;meanwhile, a current stepping control end of the current injection switch module and a driving input end of the level extraction control circuit are connected to a preset control signal output end ofthe phase frequency detector, which is used for controlling the current injection switch module to inject charges according to the level width change condition of the output signal of the preset control signal output end until the phase of the reference clock signal input by the phase frequency detector is synchronous with the phase of the feedback clock signal. The low-pass filter receives charges injected by the current injection switch module under the control on-off action of the phase-locked accelerating circuit, the charges are rapidly injected into the low-pass filter until the chargesare close to be stable, meanwhile, oscillation can be avoided through stepping charge injection, and the phase-locked time is shortened.

Description

technical field [0001] The invention belongs to the technical field of phase-locked loops, and in particular relates to a phase-locked acceleration circuit and a phase-locked loop system based on level width extraction. Background technique [0002] A phase-locked loop (PLL) is a very important functional system, such as providing one or more frequency-required clocks in a chip system, generating local oscillator signals in a receiver, and maintaining synchronization in a communication system. For these systems, the fast locking of the phase-locked loop has always been the goal, but due to the mutual constraints of factors such as stability, dynamic response, precision and noise, it is difficult to further improve the phase-locking speed. [0003] In the phase-locked loop, a frequency detector, a charge pump, a low-pass filter, a voltage-controlled oscillator and a frequency divider form a feedback loop, and the high-frequency output signal of the voltage-controlled oscillat...

AI Technical Summary

Problems solved by technology

However, in this process, the delay time of the loop feedback is longer, and the phase locking time of the phase-locked loop is longer.

Images