Patent ID: 6624705
Filing Date: 2003-09-23
Classification: H03L

Abstract:
An apparatus including a control circuit for a phase-locked loop (PLL) with reduced cycle slip during acquisition of phase lock, comprising:reference division circuitry that, responsive to a reference division control signal, receives and frequency-divides a reference signal with an associated reference signal frequency to provide a frequency-divided reference signal with associated first and second frequency-divided reference signal phases and frequencies corresponding to first and second values of said reference division control signal; feedback division circuitry that, responsive to a feedback division control signal, receives and frequency-divides a feedback signal with an associated feedback signal frequency to provide a frequency-divided feedback signal with associated first and second frequency-divided feedback signal phases and frequencies corresponding to first and second values of said feedback division control signal; phase comparison circuitry, including output current circuitry and coupled to said reference and feedback division circuitry, that compares said frequency-divided reference and feedback signal phases and in response to said phase comparison and a current control signal provides an output state signal and an output current signal with first and second output current signal value ranges corresponding to first and second values of said current control signal; and control circuitry, coupled to said phase comparison circuitry and said reference and feedback division circuitry, that, responsive to a phase lock control signal and said output state signal, provides said current control signal and said reference and feedback division control signals; wherein a first ratio of said first and second frequency-divided reference signal frequencies, a second ratio of said first and second frequency-divided feedback signal frequencies and a third ratio of said first and second output current signal value ranges are mutually corresponding.