Phase lock loop circuits and methods including multiplexed selection of feedback loop outputs of multiple phase interpolators

Abstract

A phase lock loop circuit includes a phase frequency detector, a voltage controlled oscillator, a phase interpolator, a clock signal selector, a selection module, a multiplexer, and a divider. The phase frequency detector compares phases of a reference clock and frequency divided output signals and generates an error signal. The voltage controlled oscillator, based on the error signal, generates a phase lock loop output signal and output clock signals. The phase interpolator phase interpolates the output clock signals to generate an interpolator output signal. The clock signal selector selects one of the output clock signals. The selection module generates a selection signal based on states of the interpolator output and selected output clock signals. The multiplexer, based on the selection signal, selects the interpolator output signal or the selected output clock signal. The divider frequency divides an output of the multiplexer to provide the frequency divided output signal.