Low pass filter corner frequency tuning circuit and method
US6710644B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 29, 2001 |
| Grant date | Mar 23, 2004 |
| Priority date | — |
| Expiry date | Nov 29, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D2200/0047
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An integrated circuit formed on a semiconductor chip, comprising a low pass filter circuit having a first resistor of a first resistance value and a capacitor of a first capacitance value, wherein the first resistance value and the first capacitance value determine a corner frequency of the filter; and a tuning circuit having a second resistor of a second resistance value, a switched-capacitor of a third resistance value and a comparator that compares two voltage signals to produce a control signal, wherein the control signal adjusts the first and second resistance values as a function of the third resistance value. The corner frequency of the filter can be adjusted by varying one or more reference voltage signals. In combination, the corner frequency of the filter is adjusted by changing the frequency of a clock that controls the switched-capacitor to decrease the circuit sensitivity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.