17.1: SRAM‐based LED CMOS driver circuit for a 512x512 GaN microdisplay

Abstract

GaN microLED technology has the potential to offer displays with high brightness, bandwidth, and long lifetime with a very low energy consumption. Moreover, GaN‐on‐Si hybrid interconnection technology allows the development of displays with a very high pixel density integration. In this work we present an in‐pixel driving circuit designed in a 0.18µm CMOS technology to be integrated on a 512x512 microLED array by using the KlettWelding hybrid interconnection technique forming a microLED display of 1411 ppi with 10kfps working speed. The pixel driver is able to achieve switching times of 1MHz and can be operated at high bias currents of 120µA. The individual driver consists of 4 SRAMs that apply a weighted current and allows to avoid the current stability problems associated to CMOS backplanes in hybridly interconnected displays.