Multilevel analog to digital data converter having dynamic element matching in a reference data path
AssigneeAudio Logic, Inc.
InventorJohn Laurence Melanson
Life of this patent
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Abstract
In a delta sigma analog to digital converter, generally comprising a noise shaping filter element fed into a multilevel quantizer, the output of which is the output of the delta sigma modulator and is also fed through a digital to analog converter array in a feedback loop to the noise shaping filter, dynamic element matching circuitry is included in the quantizer, in a reference path. The quantizer includes dynamic element matching circuitry for shaping the usage of the elements of the quantizer. Specifically, reference voltages are switched to specific comparators according to control signals from switch control circuitry.
Claims11
A multilevel analog to digital converter (ADC) having a noise shaping filter feeding a multilevel quantizer having comparators fed by reference levels and a signal from the noise shaping filter, the quantizer providing an ADC output signal and providing a feedback signal to a digital to analog converter (DAC), the output of the DAC being combined with the ADC input and provided to the noise shaping filter, the improvement comprising:
- the multilevel quantizer includes dynamic element matching circuitry (DEM) including switches for selectively switching the reference levels provided to the comparators in the quantizer during operation of the ADC;
- and
- DEM switch control circuitry to control the DEM switches.
A multilevel analog to digital converter (ADC) comprising:
- a noise shaping filter having an ADC input;
- a multilevel quantizer having comparators fed by reference levels and a signal from the noise shaping filter;
- wherein the quantizer provides an ADC output signal and a feedback signal;
- and
- a digital to analog converter array for converting the feedback signal and providing it as an input to the quantizer;
- wherein the multilevel quantizer includes dynamic element matching circuitry (DEM) including
- switches for selectively switching the reference levels provided to the comparators in the quantizer during operation of the ADC;
- and
- DEM switch control circuitry to control the DEM switches.
A method for noise shaping elements in a quantizer having comparators fed by reference signals and fed by a noise shaper, the quantizer providing an output and a feedback signal to the noise shaper, the method comprising the steps of:
- receiving previous outputs of the comparators, and
- switching the reference signals provided to the comparators according to the received outputs.
Dependencies are inferred from the claim text.