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

Abstract

Abstract— 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.

Low‐temperature poly‐Si TFT‐LCD with an integrated analog circuit

“…To date, several attempts have been reported to integrate a D/A converter and amplifier using LTPS TFT technology. 6,7 However, a driving voltage of more than 10 V was needed for the analog circuit. According to our calculations, such a higher driving voltage would cause problems with the power dissipation of the analog circuit.…”