Digitally controlled oscillators
US8031011B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 27, 2008 |
| Grant date | Oct 4, 2011 |
| Priority date | — |
| Expiry date | Oct 2, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K2005/00071
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Oscillator circuitry is provided that is based on a ring of inverters. The ring of inverters may be single-ended or differential inverters. Digitally controlled adjustable load capacitors may be provided at inverter outputs to tune the oscillator circuitry. Each digitally controlled adjustable load capacitor may be formed from multiple varactors connected in parallel. Each varactor may have a control input that receives a digital control signal. The digitally controlled adjustable load capacitors in a given oscillator may be adjusted in unison to produce the same capacitance value for each capacitor or may be adjusted individually so that they produce different capacitance values. The inverters may include common-mode-gain reduction features such as series-connected current sources, series-connected resistors, and cross-coupled negative feedback transistors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.