Differential VCO and quadrature VCO using center-tapped cross-coupling of transformer
US8212625B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 13, 2008 |
| Grant date | Jul 3, 2012 |
| Priority date | — |
| Expiry date | Jul 27, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03B5/1296
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Provided are a differential voltage-controlled oscillator (VCO) and a quadrature VCO using center-tapped cross-coupling of a transformer. The differential VCO and the quadrature VCO can be driven by low power through a current reuse structure and have an excellent phase noise characteristic by center-tapped cross-coupling through a transformer. Further, variable capacitance units for frequency variation are divided into variable capacitance units for coarse tuning and variable capacitance units for fine tuning. Therefore, it is possible to obtain a wide tuning range while voltage oscillation gain is reduced. Further, the differential VCO and the quadrature VCO are configured in such a manner that the respective variable capacitance units operate linearly throughout the entire capacitance region due to control voltage distribution by resistors. Accordingly, it is possible to obtain a linear control voltage-oscillation frequency characteristic. The quadrature VCO according to the present invention can output four-phase quadrature signals while having an excellent phase noise characteristic, without substrate loss and current consumption caused by the switching transistors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.