Patent ID: 7764129
Filing Date: 2010-07-27
Classification: H03L

Abstract:
1. A method of startup for a phase-locked loop (PLL), the method comprising: at initiation of the PLL, providing a reference voltage from a startup voltage source to an input of a voltage controlled oscillator (VCO) in the PLL, wherein the reference voltage is set to a predetermined minimum voltage; stepwise increasing the reference voltage from the predetermined minimum voltage; comparing a frequency of a reference signal input to the PLL with a frequency of a feedback signal originating from an output of the VCO of the PLL to determine a frequency differential as the reference voltage increases; determining whether a convergence criterion is met according to the frequency differential; while the convergence criterion is not met, increasing the reference voltage; and when the convergence criterion is met, replacing the reference voltage provided by the startup voltage source with an operational voltage generated by an operational voltage source.