Low phase noise differential LC tank VCO with current negative feedback
US7414488B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 2006 |
| Grant date | Aug 19, 2008 |
| Priority date | — |
| Expiry date | Nov 25, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03B2200/0074
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A differential voltage controlled oscillator (VCO) employed in a frequency synthesizer used as a local oscillator of a wireless communication on-chip transmitter/receiver is provided. More particularly, a differential current negative feedback VCO equipped with a current-current negative feedback circuit that suppresses low- and high-frequency noise is provided.A differential current negative feedback VCO includes a resonator determining oscillation frequency, and an oscillator generating negative resistance. In the oscillator of the differential current negative feedback VCO, transistors Q1 and Q2 form a cross-coupled pair, and negative resistance is generated by positive feedback of the cross-coupled pair. And, transistors Q1 and Q3 together with an emitter resistor and a capacitor form a current negative feedback part, and transistors Q2 and Q4 together with an emitter resistor and a capacitor form another current negative feedback part which is disposed opposite to a resonator. Thus, the VCO operates differentially.In the oscillator of the differential current negative feedback VCO, emitter noise currents generated by base noise voltages of Q1 and Q2 induced by low- and high-fr…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.