High-speed rail-to-rail output buffer amplifier with dynamic-bias circuit

The design of a high-speed output buffer amplifier for driving the large column line loads of large-size TFT-LCDs is presented. The major circuit of the output buffer is a rail-to-rail current mirror amplifier which can control the class-AB output stage and auxiliary output stage at the same time. The proposed dynamic bias method not only increases the driving capability of the class-AB output stage but also maintains a small quiescent current path.