Delay-locked loop circuitry for clock delay adjustment
US6125157A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 6, 1997 |
| Grant date | Sep 26, 2000 |
| Priority date | — |
| Expiry date | Feb 6, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L7/0025
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Delay-locked loop circuitry for generating a predetermined phase relationship between a pair of clocks. A first delay-locked loop includes a set of delay-producing elements arranged in a chain, the chain receiving an input clock and generating, from each delay element, a set of phase vectors, each shifted a unit delay from the adjacent vector. The first delay-locked loop adjusts the unit delays in the delay chain using a delay adjustment signal so that the phase vectors span a predetermined phase shift of the input clock. A second delay-locked loop selects, from the first delay-locked loop, a pair of phase vectors which brackets the phase of an input clock. A phase interpolator receives the selected pair of vectors and generates an output clock and a delayed output clock, the amount of the delay being controlled by the delay adjustment signal of the first delay-locked loop circuitry. A phase detector compares the delayed output clock with the input clock and adjusts the phase interpolator, based on the phase comparison, so that the phase of the delayed output clock is in phase with the input clock. As a result, there is a predetermined phase relationship between the output clock an…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.