Patent ID: 6111442
Filing Date: 2000-08-29
Classification: G06F,H03L,Y10S

Abstract:
A phase-locked loop circuit with dynamic backup, comprising:a phase comparator for comparing an input reference signal and a feedback output signal to generate a voltage signal representing the phase difference between said input reference signal and said feedback output signal;a lowpass filter, coupled to said phase comparator, for filtering said voltage signal;a voltage-controlled oscillator, coupled to said lowpass filter, for generating an output signal from said filtered signal;a detection circuit, coupled to said phase comparator, for detecting whether or not said phase-locked loop circuit is in lock with said input reference signal, wherein said detection circuit directs said input reference signal to bypass said phase comparator, said lowpass filter, and said voltage-controlled oscillator, in response to detecting that said phase-locked loop circuit is not in lock with said input reference signal; anda phase-adjusting circuit for eliminating any phase shifting of said input reference signal during an initiation of said bypass.