CCT “Tunable White” drivers and fixtures have two LED arrays and two drivers: one Warm color temperature, usually 1800-2700K and one Cool (4000-6000K).  The tuning part is accomplished by mixing the amount of current going to each array separately.  A brighter warm array and more dim cool array means the light will appear warmer overall without adjusting the overall brightness.  Dimming both or raising both arrays together will dim or raise the total light output.

For David’s Perfect porch light, we can use a fixture like the U1-WS73A outdoor wall sconce and a 2-channel driver module at the PDM.  Instead of changing color temperature, the LED for ambient light and the down light are separate LEDs.  So you can adjust the total light output or change the level of the ambient light dynamically when someone approaches the porch (using a motion sensor for example).  Or change the output level depending on the time of day depending on the amount of sunlight hitting the patio surface and the walls.

This requires only one wire and two sconces can be connected in parallel if you want fixtures on each side of the door.  Use a Constant Current driver module as the fixtures are not bulbs with internal drivers or regulators.