Cross-self-bias rail-to-rail column buffer for 640-channel 6-bit TFT-LCD

A 640-channel 6-bit LCD column driver with a cross-self-bias pushpull buffer is presented. To design a column driver for thin-film transistor liquid-crystal displays (TFT-LCDs), both low power consumption and chip area are key problems that must be solved. Therefore, the proposed cross-self-bias buffer amplifier effectively reduces the circuit area and power consumption overheads of conventional class-AB biasing techniques. The 640-channel 6-bit column driver is implemented using 0.18-μm high-voltage CMOS technology. The proposed column driver is then used in an SXGA LCD panel to perform the experimental characterization. The measured performance of column driver exhibits maximum settling times of 1.4 μs and 1.2 μs for rising and falling edges, respectively, under one-dot inversion. The quiescent current consumption of the proposed rail-to-rail buffer is about 4 μA.