Charge pump circuit for a high speed phase locked loop
US6611161B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 6, 2001 |
| Grant date | Aug 26, 2003 |
| Priority date | — |
| Expiry date | Nov 6, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/0896
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A charge sharing suppression circuit for a charge pump circuit in a phase locked loop is disclosed that is capable of suppressing charge sharing due to static phase error in the phase locked loop. A return path is provided to allow charge pump currents to flow when static phase error exists. A first switch in the return path closes in response to an UP signal from a phase frequency detector and a second switch closes in response to an inverted version of a DN signal. A third switch in the return path closes in response to an inverted version of an UP signal and a fourth switch closes in response to a DN signal. The return path is disabled in the absence of static phase error.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.