Multi-bit successive-approximation register analog-to-digital converter
AssigneeTexas Instruments Incorporated
InventorsRishi Soundararajan, Visvesvaraya Pentakota, Anand Jerry George
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Abstract
A system for digitizing a sampled input value includes a digital-to-analog converter for generating an output signal as a function of (1) the sampled input value, (2) a reference value, and (3) digital codes, and a multi-bit analog-to-digital converter for determining the digital codes in first, intermediate, and subsequent cycles. Dither is dynamically added to the digital-to-analog converter in the intermediate cycle. The dither is corrected for in the subsequent cycle.
Claims20
A system for digitizing a sampled input value, comprising:
- a digital-to-analog converter for generating an output signal as a function of (1) the sampled input value, (2) a reference value, and (3) digital codes;
- and
- a multi-bit analog-to-digital converter for determining the digital codes in first, intermediate, and subsequent cycles;
- wherein dither is dynamically added to the digital-to-analog converter in the intermediate cycle, and corrected for in the subsequent cycle.
A system for digitizing an analog input voltage, comprising:
- a digital-to-analog converter for generating an output voltage as a function of (1) the input voltage, (2) a reference voltage, and (3) digital codes, wherein the digital-to-analog converter includes a capacitor array which is responsive to the digital codes;
- and
- a multi-bit successive-approximation register analog-to-digital converter for receiving the output voltage and determining the digital codes based on the output voltage in first, intermediate, and subsequent cycles;
- wherein the capacitor array has a dither capacitor to which dither is dynamically added during the intermediate cycle;
- and
- wherein dither is not applied to the dither capacitor during the subsequent cycle, and wherein the digital codes are corrected for by the analog-to-digital converter during the subsequent cycle.
A method of digitizing an analog input voltage, comprising:
- sampling the input voltage;
- subsequently, in a first cycle, using a capacitor array to generate a first output voltage as a function of (1) the input voltage, (2) a reference voltage, and (3) digital codes, and using a multi-bit successive-approximation register analog-to-digital converter to determine first digital codes;
- subsequently, in an intermediate cycle, dynamically adding dither to a capacitor of the capacitor array to reduce the formation of higher-order harmonics in an output signal, using the capacitor array to generate an intermediate output voltage as a function of the input voltage, a reference voltage, and the first digital codes, and using the multi-bit successive-approximation register analog-to-digital converter to determine second digital codes;
- subsequently, using the capacitor array to generate a subsequent output voltage as a function of the input voltage, a reference voltage, and the first and second digital codes, and using the multi-bit successive-approximation register analog-to-digital converter to determine a third digital code for correcting the second digital codes;
- and
- subsequently, using the first, second, and third digital codes to cause the output signal to be representative of the input voltage.
Dependencies are inferred from the claim text.