Analog-to-digital converter with sigma-delta duty cycle encoded output
US5559514A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 9, 1994 |
| Grant date | Sep 24, 1996 |
| Priority date | — |
| Expiry date | Aug 9, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M3/506
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An analog-to-digital converter employs a sigma-delta modulator that produces a pulsed output with an average duty cycle that varies with an analog input to the modulator. A counter averages the modulator's output duty cycle, and feeds the averaged information onto a one-line transmission circuit for delivery to a remote location. Both the sigma-delta modulator and the counter are synchronized to the same local clock, so that the counter's duty cycle remains substantially constant even if the clock frequency varies. This allows for a simple clock configuration that can be integrated along with the sigma-delta modulator and counter on a single IC chip of reasonable size. When used for temperature sensing, the counter's output duty cycle provides an indication of the locally sensed temperature, independent of temperature-induced variations in the clock frequency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.