Integrated switched-capacitor filter with improved frequency characteristics
US4769612A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 15, 1987 |
| Grant date | Sep 6, 1988 |
| Priority date | — |
| Expiry date | Oct 15, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H19/004
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A switched-capacitor filter constituted in the form of a semiconductor integrated circuit has an input circuit which consists of at least one noninversion-type switched-capacitor and at least two inversion-type switched-capacitors that are connected in parallel with each other. The two inversion-type switched-capacitors have different writing timings and reading timings relative to each other. With this setup, capacitances of the switched-capacitors need not be extremely increased even when it is desired to maintain a zero-point frequency of the filter at a very low value. Further, there is no need of providing a circuit such as sample holding circuit which requires extra area and consumes additional electric power.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.