Variable delay line with multiple hierarchy
US7274236B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 15, 2005 |
| Grant date | Sep 25, 2007 |
| Priority date | — |
| Expiry date | May 31, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K2005/00156
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Disclosed herein are improved, simplified designs for a hierarchical delay line (HDL). The HDL is useful in providing precise phase control between an input clock signal and an output clock signal, and has particular utility as the variable delay in a delay-locked loop (DLL). In one embodiment, a coarse unit delay provides a delayed representation of an input clock. The original and delayed versions of the input clock are presented to a phase mixer block, which is controllable to weight its output to a phase between one of the two input clock signals. The output of the phase mixer block is then provided to a controllable variable delay line capable of adding further coarse delay into the processed signal. To assist in boundary switching, multiplexers are provided in the path between the original and delayed versions of the input clock and the phase mixer block, which provides the ability to boundary shift without having to reset the phase mixer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.