Phase-locked loop suspension and recovery method

Abstract

The invention discloses a phase-locked loop suspension and recovery method, and belongs to the technical field of electronics and circuits. The method comprises the steps that after a phase-locked loop is started and locked, an output voltage of a loop filter is kept on a capacitor in the loop filter by disconnecting the loop filter from a phase detector and a voltage-controlled oscillator; an input signal of the controlled oscillator is pulled down to a ground level, and the voltage controlled oscillator is turned off, so that the phase locked loop is suspended; after the phase locked loop issuspended, the connection of the loop filter and the phase detector and the voltage controlled oscillator is recovered, and the connection of the input signal of the voltage controlled oscillator with the ground level is cut off, the output voltage of the loop filter kept on the capacitor in the loop filter when the phase locked loop is suspended is taken as a an input signal of the voltage controlled oscillator so as to control the voltage controlled oscillator to vibrate, thereby achieving the recovery of the work of the phase locked loop. The method can control the suspension and recoveryof the phase-locked loop, and achieves the purposes of shortening the startup time of the phase-locked loop and reducing the power consumption.

Description

technical field [0001] The invention belongs to the technical field of electronic circuits, and in particular relates to a method for suspending and resuming a phase-locked loop. Background technique [0002] In electronic circuits, the phase-locked loop circuit is an important circuit. The phase-locked loop circuit is generally used for frequency multiplication and synthesis, reducing phase offset and clock jitter, etc., thereby generating the required clock signal. In digital circuits and It is widely used in analog circuits. In the process from the closed state to the open state, the phase-locked loop has to go through two stages: the transient process and the loop adjustment process, and the transient process generally takes a long time. From the perspective of low power consumption, some applications need to turn off the PLL for certain periods of time, and then turn the PLL back on when the clock signal is needed, but for some systems, the process of restarting the PL...

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Problems solved by technology

[0003] Aiming at the problem of high power consumption caused by long time-consuming transient process when the phase-locked loop is restarted, the present invention proposes a method for suspending and resuming the phase-locked loop, which makes the phase-locked loop Pause the work, and when the PLL needs to work, the PLL skips the transient process and directly enters the loop adjustment process to resume work, so as to shorten the start-up time and reduce power consumption

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