Head lamp control method and apparatus, with PWM output regulation
US4841198A · kind A · utility
40Cited by
8References
9Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Oct 19, 1987 |
| Grant date | Jun 20, 1989 |
| Priority date | — |
| Expiry date | Oct 19, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/00
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A pulse width modulation control unit for energizing a vehicle head lamp. During daylight operation of a motor vehicle the control unit energizes the head lamp by pulse width modulating the battery output and coupling the modulating output across the head lamp. As battery voltage changes the pulse width modulation is adjusted to maintain power output of the head lamp. An over current condition in a switching transistor is monitored and used to de-activate the pulse width modulation of the head lamp energization.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.