US Patent 10201049 Local display backlighting systems and methods

Aspects of the subject technology relate to control circuitry for light-emitting diodes. The control circuitry includes a two-dimensional light-emitting diode (LED) array. The control circuitry may include a single LED array operable by a common driver or multiple LED arrays each operable by a dedicated LED matrix driver. Each matrix driver may receive a synchronization signal from a common controller and may include a programmable phase lock loop (PLL) to synchronize each matrix driver to the synchronization signal. The LED array may include multiple strings of LEDs mounted in series along the string. Each LED in each string may include a bypass switch operable to modify the current through that LED by pulse-width modulation.