Apparatus and associated methods relate to modular series-connectable LED light strings having an input connector and an output connector for electrically communicating power and a control signal, an input control signal being actively level-shifted to a level suitable to a first lighting element of the LED light string. In an illustrative embodiment, the LED light string may have a plurality of series connected lighting elements that generate a series of intermediate supply voltage levels. In some embodiments, the active level shifter may bias the input control signal between an DC voltage level applied to a positive supply pin of the first lighting element and the intermediate supply voltage level generated at the connection of a negative supply pin of the first lighting element and the positive supply pin of the second lighting element. In some embodiments, active level-shifting may advantageously restore the proper bias for a series connected light string.
