Continuous tuning of switched capacitor circuits using DC-isolated tuning elements
US6011432A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 23, 1998 |
| Grant date | Jan 4, 2000 |
| Priority date | — |
| Expiry date | Jul 23, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H19/004
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Circuits having switched capacitors that are implemented with T-structures in which one of the three capacitors in the T-structure is implemented with a buffer amplifier configured to receive a control signal (e.g., a control voltage) and to apply a buffered control signal to an active device having a capacitance that is dependent on the control signal level. In one embodiment, the control signal is a control voltage, the active device is a varactor diode, and the circuit is a ladder filter having one or more switched capacitors, each of which is implemented using the T-structure of the present invention. Under the present invention, continuously tunable circuits can be implemented with discrete elements where the circuits can be tuned by changing the control signal in one or more of the switched capacitors, without having to provide a continuously tunable clock.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.