Multi-bit sigma-delta analog to digital converter with a variable full scale
AssigneeAnalog Devices, Inc.
InventorsRichard Schreier, Lawrence Singer, Jennifer A. Lloyd
Life of this patent
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Abstract
A multi-bit sigma-delta analog to digital converter has a quantizer, a loop filter circuit, and a digital to analog feedback circuit. The quantizer, loop filter, and digital to analog feedback circuit have a loop gain associated therewith. The quantizer and loop filter have a combined gain associated therewith. The full-scale of the digital to analog feedback circuit is varied. The combined gain of the quantizer and loop filter is also varied. More specifically, the combined gain of the quantizer and loop filter is varied in inverse proportion to the full-scale of the digital to analog feedback circuit to maintain the loop gain at a substantially constant level.
Claims18
A method for varying an input full-scale level of a multi-bit sigma-delta analog to digital converter having a quantizer, a loop filter circuit, and a digital to analog feedback circuit;
- the quantizer, loop filter circuit, and digital to analog feedback circuit having a loop gain associated therewith;
- the quantizer and loop filter circuit having a combined gain associated therewith, comprising:
- (a) varying a full-scale of the digital to analog feedback circuit;
- and
- (b) varying the combined gain of the quantizer and loop filter circuit in inverse proportion to the full-scale of the digital to analog feedback circuit to maintain the loop gain at a substantially constant level.
A multi-bit sigma-delta analog to digital converter, comprising:
- a quantizer,
- a loop circuit, operatively connected to said quantizer, including a digital to analog feedback circuit;
- and
- a reference signal source to provide a reference signal;
- said quantizer and said loop circuit having a loop gain associated therewith;
- said digital to analog feedback circuit, in response to said reference signal, varying a full-scale thereof;
- said quantizer, in response to said reference signal, changing thresholds thereof.
A multi-bit sigma-delta analog to digital converter, comprising:
- a quantizer,
- a loop circuit, operatively connected to said quantizer, including a digital to analog feedback circuit and a variable gain element;
- and
- a gain control signal source to provide a gain control signal and a full-scale control signal;
- said quantizer and said loop circuit having a loop gain associated therewith;
- said digital to analog feedback circuit, in response to said full-scale control signal, varying a full-scale thereof;
- said variable gain element, in response to said gain control signal, varying a gain thereof.
Dependencies are inferred from the claim text.