Precision analog-to-digital converter with low-resolution and high-resolution conversion paths
US5446371A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 12, 1994 |
| Grant date | Aug 29, 1995 |
| Priority date | — |
| Expiry date | May 12, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/822
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An analog-to-digital converter utilizes low-resolution and high-resolution conversion paths for precision voltage measurements. A first conversion made using a comparatively low resolution ADC is used to predict the reference voltage to one input of a null detector that receives the input voltage on another input, and effectively magnifies the voltage difference between its inputs. In a preferred embodiment, the duty cycle of a pulse-width modulator is adjusted to precisely adjust the reference voltage to provide a nulled (or near null) reading from the null detector. A low resolution ADC then converts the voltage from the null detector, which when added to the reference voltage, yields a final reading with 18-bit to 22-bit accuracy. The preferred embodiment is implemented to read the output from a pressure transducer and employs a binary search technique to rapidly adjust the duty cycle of the pulse-width modulator. The system utilizes a single ADC which is multiplexed between the low-resolution, high-speed reading and high-resolution, low-speed reading of the fully settled output of the null detector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.