Lighting control apparatus of lighting device for vehicle
US7482765B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 11, 2006 |
| Grant date | Jan 27, 2009 |
| Priority date | — |
| Expiry date | Jan 30, 2027 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/30
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
When a forward direction voltage of any of several LEDs 14 to 20 is lowered, a drain voltage of an NMOS transistor 70 employed in any of series regulators 24 to 30 becomes higher than a defined voltage. A zener diode ZD1, which is connected to the LED where the abnormal condition occurs, becomes conductive. A voltage, which is increased from the defined voltage, is applied to a negative input terminal of a comparing amplifier 72, and an output voltage of the comparing amplifier 72 is lowered by this increased voltage portion so that a gate voltage of the NMOS transistor 70 is lowered. A current flowing through the NMOS transistor 70 is decreased. Even if an abnormal condition caused by a voltage drop occurs in any of the LEDs 14 to 20, then the LEDs 14 to 20 can be protected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.