Digitally calibrated delta-sigma analog-to-digital converter
US4943807A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 13, 1988 |
| Grant date | Jul 24, 1990 |
| Priority date | — |
| Expiry date | Apr 13, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M3/458
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A self-calibrated analog-to-digital converter with a corrected output includes an analog modulator (18) for receiving an analog input voltage and outputting a pulse train having a value proportional to the analog input voltage. The pulse train is filtered by a digital filter (20) which has the output thereof input to a calibration module (24). The calibration module (24) is controlled by a calibration control circuit (28) and is operable to correct the output to account for offset and gain errors. Prestored calibration parameters in a register (30) are utilized for this compensation. In a self-calibration mode, the control circuit (28) is operable to control a calibration multiplexer (12) to select a zero-scale input voltage on a terminal (16) and a full-scale reference voltage on a terminal (14) for input to the modulator (18). The multiplexer (12) is controlled to selcet the zero-scale reference to calculate an offset value for storage in the register (30) and then subsequently select the full-scale reference to calculate a scale factor for storage in the register (30 ). The self-calibration mode utilizes a settling counter (36) to insure that the output of the filter (20) has se…
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