Digital phase lock loop

Abstract

A system includes a digital phase lock loop (PLL) constructed from an all digital circuit implementation and standard cell construction. The digital PLL includes a digital frequency synthesizer and a digital phase detector. The digital frequency synthesizer includes a digital DLL including a plurality of delay chains, each of the delay chains including at least one digitally programmable delay element for configuring the plurality of delay chains to achieve a phase lock with an input reference signal. The digital frequency synthesizer also a non-glitching MUX electrically coupled to the digital DLL for selecting a tap output from one of the at least one digitally programmable delay element to select at least one pulse glitch-free from the selected output tap, and a phase accumulator electrically coupled to the non-glitching MUX for precisely dividing a timing period of the input reference signal and for selecting a tap output from one of the at least one digitally programmable delay element to select at least one pulse at a precise point in the timing period from the output tap. The digital phase detector, is electrically coupled to the digital frequency synthesizer to compare an edge of the input reference signal to an edge of a synthesized signal to provide a digital code information representing a phase error between the edge of the input reference signal and the edge of the synthesized signal.