42V-PWM - Lighting the Way in the New Millennium

As the vehicle electrical system migrates to the recommended 42-volt system in the future, 42V incandescent lamps will not be practical due to their short filament life. Alternatives to incandescent lamps are discussed. However, due to the inherent simplicity and cost advantage over alternatives, incandescent lamps remain the light source of choice for the auto manufacturer. A scheme to power the current 12V incandescent lamp directly from the 42V line will be presented as a viable low cost solution for the 42V system. This scheme utilized pulse width modulation (PWM) which eliminates the use of expensive DC to DC converters. Implementation schemes, preliminary results, advantages and issues are presented.