Delta-sigma analog-to-digital converter topology with improved distortion performance
AssigneeTexas Instruments Incorporated
InventorsAmit K. Gupta, Peng Cao, Venkatesh Acharya
Life of this patent
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Abstract
A delta-sigma Analog-to-Digital Converter (ADC) (IC) which includes an input feed-forward path extending from an input to the ADC to a feed-forward summing circuit disposed between a loop filter and quantizer of the ADC, and a filter disposed in the feed-forward path as an apparatus for improving distortion performance in the delta-sigma ADC. The filter may be a low pass filter, for example, a Resistor-Capacitor (RC) circuit. The filter may have a cut-off frequency outside the ADC's passband. The filtering provided may be continuous-time filtering, even if the delta-sigma ADC is a discrete-time delta-sigma ADC.
Claims13
A method for operating a discrete-time delta-sigma analog-to-digital converter (DT-DSADC) comprising:
- filtering, by a continuous-time filter, an input signal at an input terminal of the DT-DSADC, the continuous-time filter disposed in a feed-forward path of the DT-DSADC, the feed-forward path extending from the input terminal to a feed-forward summing circuit disposed between a discrete-time loop filter and a quantizer of the DT-DSADC;
- and
- sampling, by a feed-forward sampler, the filtered input signal, the feed-forward sampler disposed after the continuous-time filter in the feed-forward path of the DT-DSADC.
A discrete-time delta-sigma analog-to-digital converter (DT-DSADC), the apparatus comprising:
- a continuous-time filter disposed in a feed-forward path of the DT-DSADC, the feed-forward path extending from an input terminal of the DT-DSADC to a feed-forward summing circuit, the feed-forward summing circuit disposed between a discrete-time loop filter and a quantizer of the DT-DSADC;
- and
- a feed-forward sampler disposed after the continuous-time filter in the feed-forward path of the DT-DSADC.
Dependencies are inferred from the claim text.