An illumination device described herein includes at least a phosphor converted LED, which is configured for emitting illumination for the illumination device, a first photodetector and a second photodetector. A spectrum of the illumination emitted from the phosphor converted LED comprises a first portion having a first peak emission wavelength and a second portion having a second peak emission wavelength, which differs from the first peak emission wavelength. The first photodetector has a detection range, which is configured for detecting only the first portion of the spectrum emitted by the phosphor converted LED. The second photodetector has a detection range, which is configured for detecting only the second portion of the spectrum emitted by the phosphor converted LED. Methods are provided herein for calibrating and controlling each portion of the phosphor converted LED spectrum, as if the phosphor converted LED were two separate LEDs.