This paper presents an OLED display driver IC with a high‐ gain fast‐slew(HGFS) and an on‐the‐fly self‐repair(OFSR) circuits for a spatial resolution of WQHD and a frame rate of 120Hz To reduce a settling time of a source driver as resolution andframe rate are increase, the proposed HGFS circuit increases a slewing current of unity‐gain amplifier of source driver when an input voltage is largely changed. In addition, to improve image quality by display line defect, the OFSR circuit is operated by replacing a failure channel to a spared dummy channel. The OLED display driver IC was fabricated using a 28nm high‐ voltage process with 8V/20V transistors which has source drivers of 2,880‐channels for WQHD display. The measurement results show the horizontal line time of 2.7ps with slew rate of 7.675V/ps, which support WQHD resolution and 120Hz frame rate. Also, the demonstrated image shows that a display vertical line defect is disappeared by using OFSR.