Switched capacitor filter circuit having reduced offsets and providing offset compensation when used in a closed feedback loop

1. Field of the Invention A switched capacitor filter circuit having reduced offsets and providing offset compensation when used in a closed feedback loop includes a chopper stabilized amplified filter circuit which amplifies and low pass filters its input data signal to produce an output signal wit...

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Bibliographische Detailangaben
1. Verfasser: Lewicki, Laurence Douglas
Format: Patent
Sprache:eng
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Beschreibung
Zusammenfassung:1. Field of the Invention A switched capacitor filter circuit having reduced offsets and providing offset compensation when used in a closed feedback loop includes a chopper stabilized amplified filter circuit which amplifies and low pass filters its input data signal to produce an output signal with an out of band signal frequency component which is at the chop signal frequency and represents an offset and 1/f noise of the chopper stabilized amplified filter circuit. An output switched capacitor filter circuit which is synchronized with the chopper stabilized amplified filter circuit filters this signal with a stopband filter frequency response that virtually eliminates such out of band signal frequency component. When used in a closed feedback loop, this filtered signal is used to generate an offset compensation signal that corresponds to the residual offset within the output signal resulting from the amplifying and filtering of the input data signal. This offset compensation signal is then added to the input data signal prior to its amplification and filtering by the chopper stabilized amplified filter circuit.