A tunable light-emitting diode (LED) lamp for producing an adjustable light output. In one embodiment, the LED lamp includes a drive circuit for driving LED dies in one of a plurality of light output configurations (e.g., a pre-sleep configuration, a phase-shift configuration, and a general lighting configuration). Further, the LED lamp may include an output-select controller and/or input sensor electrically coupled to the drive circuit to select the light output configuration. As such, the LED lamp is tunable to generate different levels of spectral output, appropriate for varying biological circumstance, while maintaining a commercially acceptable light quality and color rendering index.
