Switched capacitor circuit capable of eliminating clock feedthrough by complementary control signals for digital tuning VCO
US7015742B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 20, 2003 |
| Grant date | Mar 21, 2006 |
| Priority date | — |
| Expiry date | Oct 6, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03B5/04
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A differential switched capacitor circuit for use in a voltage controlled oscillator (VCO) capable of eliminating clock feedthrough and preventing an unwanted momentary frequency shift and drift in the VCO output frequency when the switched capacitor circuit is shut off. A center switch element connects a positive side capacitance node with a negative side capacitance node depending on a first control signal. A positive side primary switch element and a negative side primary switch element connect the positive and negative side capacitance nodes depending on the first control signal. A positive side additional switch element and negative side additional switch element with control signals complementary to the first control signal cancel the clock feedthrough of the center switch and the positive and negative side primary switch elements at the positive and negative side capacitance nodes respectively.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.