Phase-locked loop or delay-locked loop circuitry for programmable logic devices

摘要

A programmable logic device is provided with phase-locked loop ("PLL") or delay-locked loop ("DLL") circuitry in which the feedback loop circuitry substantially parallels and duplicates a portion of the clock signal distribution network on the device that receives the main PLL/DLL output signal. In this way the distributed feedback loop circuit more readily provides aL substantially exact match for the distributed delay experienced by the signal propagating through the clock signal distribution network that the PLL/DLL circuitry serves.