Digitally controlled delay lines with fine grain and coarse grain delay elements, and methods and systems to adjust in fine grain increments

Abstract

Digitally controllable delay lines including fine grain and coarse grain delay elements, and methods and system to calibrate the delay lines in fine grain increments. Calibration may include calibrating a number of fine grain elements for which a combined delay is substantially equal to a delay of a coarse grain element, and calibrating numbers of fine grain and coarse grain elements which a combined delay corresponds to a period of a reference clock. A digitally controlled delay line may be implemented as part of a digital delay locked loop (DLL), and calibration parameters may be provided to a slave DLL having a similarly implemented delay line. A digitally controllable DLL may provide relatively low-power, high-resolution over a spectrum of process, voltage, and temperature variations, and may be implemented in relatively high-speed applications previously reserved for analog DLLs.