Analog/digital converter, illuminance sensor, illumination device, and electronic device
US7554480B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 10, 2007 |
| Grant date | Jun 30, 2009 |
| Priority date | — |
| Expiry date | Jul 11, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/60
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An analog/digital converter has a charge circuit that has a charge capacitor storing an electric charge commensurate with an input current, and first and second discharge circuits that discharge the electric charge stored in the charge capacitor. While the charge capacitor is charged for a predetermined charge period, every time a predetermined amount of electric charge is stored in the charge capacitor, the electric charge stored there is discharged by the first discharge circuit. After the charge period, the electric charge remaining in the charge capacitor is discharged by the second discharge circuit. Based on the number of discharges performed by the first discharge circuit and the discharge duration of the second discharge circuit, a digital value of the voltage commensurate with the amount of electric charge with which the charge capacitor has been charged is outputted. This offers a wider input dynamic range combined with an enhanced minimum resolution without requiring complicated external control, and in addition allows measurement to be performed in less time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.