High-Speed 512x512 18 μm-Pitch Array CMOS Backplane for GaN-based Microdisplay

GaN-on-Si based hybrid microdisplays have been the revolution as point-like light sources for scientific, communications, and imaging applications because of their high-resolution, high-brightness, and high-speed capabilities. Nevertheless, the microdisplay driving circuits usually focus only on two of these characteristics. In this work, we present a CMOS backplane that aims to exploit the capabilities of the GaN-based micro-arrays. The back panel can drive an array of GaN LED pixels of up to 512x512 of 1411 PPI (pixel per inch) with an in-pixel driver that offers a bias current up to 120 μA. The smart pixel control circuit has a 4-bit grayscale resolution. Frames can be updated at up to 10 kfps. Finally, the backplane can be operated in pulsed mode, toggling the entire array between the stored frame and off state at 1 MHz. The backplane design in 180 nm CMOS process and the in-pixel driver simulations results are presented.