Ryuichi Hashido

Low-temperature poly-Si TFT data drivers for an SVGA a-Si TFT-LCD panel

— Low-temperature poly-Si TFT data drivers for an SVGA a-Si TFT-LCD panel have been developed. The data drivers include shift registers, sample-and-hold circuits, and operational amplifiers, and drive LCD panels using a line-at-a-time addressing method. To reduce the power consumption of the shift register, a dot-clock control circuit has been developed. Using this circuit, the power consumption of the shift register has been reduced to 36% of that of conventional circuits. To cancel the offset voltage generated by the operational amplifier, an offset cancellation circuit for low-temperature poly-Si TFTs has been developed. This circuit is also able to avoid any unstable operation of the operational amplifier. Using this circuit, the offset voltage has been reduced to one-third of the value without using the offset cancellation circuit. These data drivers have been connected to an LCD panel and have realized an SVGA display on a 12.1-in. a-Si TFT-LCD panel.