An apparatus and method for controlling an illumination device in an aircraft is provided. The apparatus has a light source suitable for emitting light with a wavelength in the visible range. The apparatus also has a pulse-width modulator for delivering at least one output signal that is connected to the light source and suitable for effecting brightness control of the light source. The output signal is composed from a first number of first subsignals each having a first pulse width and a second number of second subsignals each having a second pulse width shorter than the first pulse width. The brightness of the light source is adjustable by varying the first number and the second number for a brightness change and the output signal is repeated after delivery of the first number and second number of subsignals.