Dynamically calibrated successive ranging A/D conversion system and D/A converter for use therein

One aspect of the present invention provides for apparatus for dynamically calibrating the internal offsets of the various range conversion paths as well as the overall offset of a successive ranging A/D conversion system over time and temperature variations. More specifically, this apparatus includ...

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Bibliographische Detailangaben
Hauptverfasser: WEIGAND, BENJAMIN F, FRECH, JOHN W
Format: Patent
Sprache:eng
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Beschreibung
Zusammenfassung:One aspect of the present invention provides for apparatus for dynamically calibrating the internal offsets of the various range conversion paths as well as the overall offset of a successive ranging A/D conversion system over time and temperature variations. More specifically, this apparatus includes at least two time-gated integrator circuits which are respectively coupled to each of the range conversion paths of the conversion system. Each integrator is operative at predetermined times to generate a corresponding compensating signal in response to the digital code of one of the path conversion results. The compensating signals are used to dynamically calibrate the internal and overall offsets of the A/D conversion system. Further included in the apparatus are switching devices disposed at the input and feedback paths of the system to provide for appropriate system conditions at the predetermined calibration times. Another aspect of the present invention is directed to a D/A converter which may be disposed in at least one of the feedback paths of the system. The D/A converter includes apparatus for self-compensating the conversion inaccuracies thereof. An additional aspect of the present invention is directed to extending the resolution of the D/A converter to at least one additional bit, thus doubling the resolution thereof.