Method for wide-range CCT tuning that follows the black body line using two independently controlled current channels and three CCTs

A method of providing tunable lighting in a luminaire, the method comprising:

• driving two channels that carry a first input current and a second input current;
• increasing, in a converter of the luminaire, the two channels to three channels that carry one set of three currents selected from a first set of three currents and a second set of three currents, selection among the first set of three currents and the second set of three currents dependent on a ratio of the first input current and the second input current;
• and
• using the one set of three currents to produce light in the luminaire based thereon.

A tunable lighting fixture comprising:

• a tunable light engine, the tunable light engine comprising:
• a dual channel light-emitting diode (LED) driver having two channels that are configured to carry a first input current and a second input current;
• a current converter configured to increase the two channels from the dual channel LED driver to three channels that carry one set of three currents selected from a first set of three currents and a second set of three currents, selection among the first and second sets of three currents being dependent on a ratio of the first input current and the second input current;
• and
• LED arrays configured to receive the one set of three currents and produce light based thereon, the LED arrays being white LEDs having correlated color temperature (CCTs) of at least one CCT of about 2700K, about 4000K, and about 6500K.