| US 7,511,570 B2 | ||
| Transconductance filtering circuit | ||
| David Chamla, Grenoble (France); Andreia Cathelin, Laval (France); and Andreas Kaiser, Villeneuve d' Ascq (France) | ||
| Assigned to STMicroelectronics SA, Montrouge (France); and Centre National de la Recherche Scientifique (CNRS), Paris (France) | ||
| Filed on Dec. 29, 2006, as Appl. No. 11/648,146. | ||
| Claims priority of application No. 05 13488 (FR), filed on Dec. 30, 2005. | ||
| Prior Publication US 2007/0194854 A1, Aug. 23, 2007 | ||
| Int. Cl. H03B 1/00 (2006.01); H03K 5/00 (2006.01); H04B 1/10 (2006.01) | ||
| U.S. Cl. 327—552 [327/553; 327/554; 327/555; 327/556; 327/557; 327/558; 327/559] | 20 Claims |
| 1. A transconductance filtering circuit comprising:
an input;
an output;
a filter coupled between the input and the output, the filter having at least two elementary cells of the same structure connected
in series, and a first capacitor connected in parallel with the at least two elementary cells, wherein each of the elementary
cells comprises:
an interconnection having an open or closed state and connected to the input and the output;
two elementary capacitors; and
a transconductance amplifier unit connected in series between the two elementary capacitors, the amplifier unit having a first
transconductance amplifier fed back onto itself via a second transconductance amplifier having a transconductance value opposite
to that of the first transconductance amplifier; and
the transconductance filtering circuit further comprising a controller to open and close the interconnection depending on
the desired configuration of the filtering.
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