A lighting apparatus that may comprise a voltage converter operable to supply a current to at least two LED channels coupled between a high voltage rail and a low voltage rail coupled to the voltage converter output is disclosed. The LED channels may be operated to selectively allow a current to flow through them. The lighting apparatus may also have a control module operable to control the total current from the voltage converter and the current through each of the LED channels. The control module may also be operable to set the respective control signals to maintain a constant total current from the voltage converter while permitting aspects of the light output including, the intensity, color, and color temperature to be set and varied. Additionally, the control module may be operable to synchronize the various control signals, obtain a representative sample of the current through the voltage converter, and operate in different modes.