Charge pump phase-locked loop of configurable start-up circuit

Abstract

The invention discloses a charge pump phase-locked loop of a configurable start-up circuit. The charge pump phase-locked loop charges a loop filter B103 through the configurable start-up circuit B107before the phase-locked loop operates, generates a start-up voltage, drives an oscillator bias generation circuit B104 to generate a bias voltage, and controls a voltage-controlled oscillator B105 tooscillate, so that the voltage-controlled oscillator starts to oscillate at a specific frequency close to a target frequency, and the activation of the phase-locked loop is completed. Compared with aconventional charge pump phase-locked loop, a user can operate the voltage-controlled oscillator at the specific frequency by a configuring signal before the phase-locked loop starts to work accordingto actual needs, thereby accelerating the locking process of the phase-locked loop after the phase-locked loop starts to work.

Description

technical field [0001] The invention relates to a charge pump phase-locked loop adopting a configurable starting circuit, which belongs to the technical field of integrated circuits. Background technique [0002] Phase-locked loop is a frequency and phase synchronization technology realized by feedback control principle, which can provide low-noise clock signal, and has been widely used in wireless communication, navigation, computer and other fields. The charge pump phase-locked loop is a typical representative of the digital-analog hybrid phase-locked loop. Its theoretical static phase error is zero, and it has significant advantages such as high speed, low jitter, and low power consumption. It is currently the most widely used phase-locked loop. [0003] With the continuous improvement of integrated circuit technology and continuous increase in scale, integrated circuit systems have higher and higher requirements for the performance of phase-locked loop circuits. The loc...

AI Technical Summary

Problems solved by technology

For the traditional charge pump phase-locked loop, the initial voltage of the loop filter is zero, and the voltage-controlled oscillator does not vibrate. Therefore, after the phase-locked loop starts to work, it takes multiple cycles of loop adjustment to make the loop The filter voltage reaches the desired value, i.e. the lock time of the PLL is longer

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