Variation of effective filter capacitance in phase lock loop circuit loop filters
US6940324B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 21, 2003 |
| Grant date | Sep 6, 2005 |
| Priority date | — |
| Expiry date | Nov 21, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L2207/04
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A structure and associated method for varying an effective capacitance within a phase lock loop circuit. The phase lock loop circuit comprises a first charge pump circuit, a second charge pump circuit, and a loop filter circuit. The loop filter circuit comprises a filter capacitor with a constant capacitance value. The first charge pump circuit is electrically connected to the loop filter. The first charge pump circuit to controls a flow of current for the loop filter. The loop filter provides a voltage for a voltage controlled oscillator. The second charge pump circuit is electrically connected to the loop filter circuit in parallel with the filter capacitor. The first charge pump circuit and the second charge pump circuit vary an effective capacitance value of the filter capacitor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.