Phase lock loop with dual state charge pump and method of operating the same
US6278333A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 29, 2000 |
| Grant date | Aug 21, 2001 |
| Priority date | — |
| Expiry date | Feb 29, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/0898
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A phase lock loop (100) includes a dual-state charge pump (120) having a first current source (220), a second current source (230) coupled in series to the first current source, a third current source (240), a fourth current source (250) coupled in series to the third current source, and control circuitry (210) coupled to the first, second, third, and fourth current sources. The charge pump can be programmed to be in an adapt mode with large up and down currents or in a normal mode with small up and down currents. The duration of the adapt mode can be programmed by a timer. The phase lock loop has a wide loop bandwidth and a faster lock time during the adapt mode and a narrow loop bandwidth and less phase noise during the normal mode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.