Patent ID: 7969248
Filing Date: 2011-06-28
Classification: H03L

Abstract:
1. A method of tuning an oscillator of a phase-locked loop (PLL) circuit, the method comprising: adjusting a coarse control signal to select one of a plurality of frequency tuning curves of the oscillator; adjusting a fine control signal to select a position on the selected frequency tuning curve, wherein a frequency of the oscillator is determined by the coarse control signal and the fine control signal; attempting to detect a lock between a feedback signal and a reference signal, wherein a frequency of the feedback signal is determined by the frequency of the oscillator; comparing the fine control signal to a reference value if the lock is detected; adjusting the coarse control signal to select a different one of the frequency tuning curves if the selected position on the selected frequency tuning curve is outside a desired tuning range; and permitting the frequency of the oscillator to settle before the coarse control signal is adjusted, wherein the frequency of the oscillator is further determined by: