Driving for multi-junction polychromic display devices

Abstract

A lighting system and method of driving an array within the lighting system are disclosed. The array includes vertically-stacked multi-color micro light-emitting diode (microLED) devices that emit light of different colors. Driving circuits and a ground switching circuit are controlled by processing circuitry to sequentially emit the colors of each microLED by independently driving pn junctions of the microLED. Each driving circuit includes multiplexers to receive a sink/source current and selectably provide the sink/source current to a channel based on control signals from the processing circuitry. Dimming of a particular color is effected using a pulse width modulated (PWM) signal to adjust a duty cycle over which the sink/source current is applied to the channel. The ground switching circuit selects another channel using multiplexers, and grounds the channel such that current is limited to flowing through one of the pn junctions at a time.