Illumination device and control method

A description is given of an illumination device which emits mixed-color light containing light of at least two different color channels (R, R 1, G, G 1, B, B 1 ). The illumination device contains at least one primary light source ( 1 ) of a first color, the light of which forms a first color channel (R, R 1, G, G 1, B, B 1 ), and at least one primary light source ( 1 ) of a second color, the light of which forms a second color channel (R, R 1, G, G 1, B, B 1 ), at least one sensor device ( 3 ), which is positioned such that it can receive mixed-color light and is suitable for detecting brightness of light of a wavelength range comprising the color channels (R, R 1, G, G 1, B, B 1 ) and which determines the brightnesses of the different color channels (R, R 1, G, G 1, B, B 1 ) separately and repeatedly during operation. Furthermore, the illumination device contains an evaluation and control device ( 4 ), which evaluates the brightness values of the color channels (R, R 1, G, G 1, B, B 1 ) and determines pulse-width-modulated electrical signals with a basic period ( 11 ) modified in such a way for the driving of the individual color channels (R, R 1, G, G 1, B, B 1 ) in such a way that the color location of the mixed-color light lies within a predetermined region of the CIE standard chromaticity diagram. A method is also described for controlling such an illumination device.