Injection-locking pll with frequency drift tracking and duty-cycle distortion cancellation

Abstract

During operation, the system uses a differential ring oscillator to generate the output clock signal. Next, the system uses a phase detector to detect errors comprising deviations between edges of the output clock signal and a reference clock signal. The system subsequently uses a frequency-tracking path to adjust a frequency of the differential ring oscillator based on the detected errors, wherein adjusting the frequency involves adjusting a supply voltage for the differential ring oscillator. The system also uses a phase-tracking path to adjust a phase of the differential ring oscillator based on the detected errors, wherein adjusting the phase involves selectively activating an injection pulse generator to inject pulses into the differential ring oscillator. Finally, the system uses a gating mechanism to periodically suppress the injected pulses produced by the injection pulse generator to enable the frequency-tracking path to detect and remediate frequency errors without interference from phase adjustments.