A circadian lighting apparatus includes a housing, two light sources, and a control logic. The first light source has a higher color temperature (e.g. 5000K) and the second light source has a lower color temperature (e.g., 1900K). The control logic can clamp operation color temperature to a mixed high color temperature (e.g., 4000K) and a mixed low color temperature (e.g., 2700K), and operate the apparatus according to a circadian schedule such that the mixed high color temperature is used for a daytime circadian state and the mixed low color temperature is used for a nighttime circadian state, and the color temperature of the apparatus is bound by the mixed high color temperature and the mixed low color temperature. This apparatus enables a personalize-able circadian light where each user can set his/her own circadian color temperature range.
