A Novel Micro‐LED Pixel Circuit Designed for Hybrid Pulse Modulation Driving Method

ABSTRACT In this paper, we presented a hybrid pulse modulation (HPP) pixel circuit for micro light emitting diode (micro‐LED) display, which was designed for low‐cost and large‐sized splicing display modules. Conventional HPP pixel circuits required two data signals per frame to control the amplitude and width of the output current pulse, respectively, which limited the size of the display modules and increased the costs. To address this problem, the pulse amplitude modulation (PAM) part of the proposed pixel circuit was specially designed to work in tandem with the pulse width modulation (PWM) part. Both of them were controlled by the same data signal. Therefore, the pixel circuit only required one data signal per frame to implement the HPP driving method, making it suitable for large‐sized display modules. Additionally, the compensation function for the threshold voltage shift and supply voltage drop was also supported by the circuit, ensuring improved image uniformity. Using theoretical analysis and circuit simulation, we demonstrated that, compared with the conventional PWM circuit, the proposed HPP pixel circuit could improve the image quality at low grayscale. Furthermore, a micro‐LED sample was tested to verify the conclusion.