A 7700-PPI 640 × 480 Micro-LED Display Backplane Driver Chip With 1.15-Transistor Pixel Circuits by Using 0.18-μm CMOS Technology

This study proposes a micro-LED display driver with 1.15-transistor pixel circuits and current-driving mode pulse width modulation (PWM). A three-stage pass transistor pixel circuit was used to transmit a driving current to micro-LEDs to shorten their off-time and achieve an average of 1.15 transistors per pixel circuit. A 7,700-PPI $640 \times 480$ micro-LED display driver operating in 8-bit current-driving mode PWM was designed and fabricated using standard 0.18- $\mu $ m CMOS technology. A down counter with parallel load function was used in each channel of the column driver to generate PWM control signals. The results of the study indicate that the display driver chip has a die dimension of $3.64 \times 4.82$ mm² and a display area of $2.11\times 1.58$ mm². In addition, the maximum DNL and INL values are 0.73 and 0.97 least significant bits, respectively. Overall, the display driver consumed 92.9 mW of power at a frame rate of 240 Hz.