Multi-phase voltage controlled oscillator (VCO) with common mode control
US6717478B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 20, 2001 |
| Grant date | Apr 6, 2004 |
| Priority date | — |
| Expiry date | Nov 20, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/0891
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A voltage controlled oscillator (“VCO”) circuit capable of generating signals with reduced jitter and/or low-phase noise is provided. One embodiment provides a plurality of cascaded VCO cells, where each VCO cell can include a source coupled differential pair, a bias transistor connected to the differential pair for biasing the differential pair, a resistive load pair connected to the differential pair, and a voltage controlled capacitor pair or varactor pair connected to the differential pair. The varactors provide control over the frequency of the oscillations produced by the VCO circuit in combination with a control voltage. A phase frequency detector combined with a charge pump and loop filter provide the control voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.