Visible light communication modulation circuit, illumination device, illumination apparatus and visible light communication system
US9780875B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 2, 2015 |
| Grant date | Oct 3, 2017 |
| Priority date | — |
| Expiry date | Apr 11, 2036 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B47/1965
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A visible light communication modulation circuit includes a modulation resistance circuit configured to change a current flowing through an LED light source by changing a resistance thereof, a measurement circuit configured to simultaneously measure a voltage applied to the LED light source and the current flowing through the LED light source at least twice until the current is stabilized, an calculation circuit configured to obtain an equivalent series resistance of the LED light source based on at least two sets of voltage values and current values and determine a target resistance of the modulation resistance circuit based on the equivalent series resistance and a predetermined modulation degree, and a conversion circuit configured to change the resistance of the modulation resistance circuit based on the target resistance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.