System with dual rail regulated locked loop

摘要

The invention relates to an apparatus comprising a plurality of delay elements to generate a plurality of incrementally delayed clock signals wherein at least one of the delayed clock signals swings between an upper supply voltage and a lower supply voltage; and a voltage control circuit coupled to provide the upper supply voltage and the lower supply voltage to each of the delay elements, the voltage control circuit configured to adjust the upper supply voltage and the lower supply voltage according to a phase difference between a selected pair of the delayed clock signals.