Operation of a filament bulb at a voltage higher than its nominal voltage, e.g. for automotive application, whereby a supply voltage is pulse width modulated at a frequency above the resonant frequency of the bulb filament

摘要

Method for operating an incandescent or filament bulb (L) at a voltage (UBatt) higher than its nominal operating voltage, whereby the voltage supply is pulse-width modulated so that the temperature of the filament is maintained at a constant temperature that is within its operating characteristic. Pulse separation is chosen so that the pulse frequency is above the filament's resonance frequency. An independent claim is made for a method for determining the resonance frequency of the filament of a filament bulb.