Abstract:
Flexible active-matrix organic light-emitting diode (AMOLED) displays offer advantages such as lightness, foldability, and rollability, which significantly enhance user experience. They have become the preferred choice for high-end portable electronic devices and show promising application potential in areas such as automotive displays. As a key component of flexible display modules, flexible touch screens introduce significant challenges for touch controller design due to increased parasitic capacitance to ground and elevated display common-mode noise resulting from their ultra-thin structure. To address these issues, this paper investigates a projected capacitive touch controller suitable for flexible AMOLED displays and proposes a solution capable of operating under high capacitive load, high noise, and high sensitivity conditions. The designed touch controller integrates 112 mutual-capacitance sensing channels, fabricated in a 180 nm CMOS process with a driving voltage of only 3.3 V. It employs a parallel driving scheme instead of the conventional sequential driving approach, substantially improving the response speed. Experimental results demonstrate that the chip achieves a signal-to-noise ratio (SNR) greater than 40 dB and a report rate of 180 Hz, exhibiting excellent noise immunity and touch sensitivity.