Circuits and methods for time-average frequency based clock data recovery

Abstract

A clock data recovery circuit includes a binary phase detector configured to receive an incoming data signal and a recovered clock, and output a phase offset signal and recovered data; a digital loop control circuit configured to receive the phase offset signal and output a control signal; and a digital frequency generator configured to receive the control signal and output the recovered clock. A method of clock recovery includes generating a digital phase offset signal from incoming data and feedback clock signals; generating a clock frequency control signal from the phase offset signal; generating a recovered clock in response to the control signal; slowing down the recovered clock when the digital phase offset signal has a first binary state; speeding up the recovered clock when the digital phase offset signal has a second binary state; and holding the recovered clock when the digital phase offset signal has a third binary state.