Photosensitive control with dynamic calibration
US7148628B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 30, 2004 |
| Grant date | Dec 12, 2006 |
| Priority date | — |
| Expiry date | Dec 8, 2024 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/40
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method and circuit arrangement dynamically calibrate a photosensitive control for a light source that includes a voltage divider circuit coupled to a resistive light detector and configured to output to a comparison circuit a variable voltage signal that varies with the resistance of the resistive light detector. To calibrate the photosensitive control, a variable impedance circuit in the voltage divider circuit is adjusted to null out any changes in voltage caused by feedback from the controlled light source. The amount of correction is proportional to the amount of light feedback. Based on the amount of correction needed, a new reference voltage is selected that will accurately detect the next dusk to dawn transition while the light feedback is present.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.