低溫複晶矽玻璃基板上之液晶顯示器驅動電路設計

Abstract

本論文利用低溫複晶矽的製程，將液晶顯示器驅動電路設計並實現在玻璃基板上。液晶顯示器的驅動電路主要分為閘級驅動電路及源級驅動電路；其中閘級驅動電路包含移位暫存器、電位轉換器和輸出緩衝器；而源級驅動電路則是由移位暫存器、閂鎖器、電位轉換器、數位對類比轉換器及輸出電壓緩衝器組成。 本論著重於將源級驅動電路實現在玻璃基板上。由於液晶顯示器具有高負載的特性，所以在輸出電壓緩衝器的部分，本論文設計了兩種具有驅動高負載功能的電路，分別為具有高旋轉率和低功率消耗的B類電壓輸出緩衝器。此外，也針對了低溫複晶矽的臨界電壓漂移問題，設計了一個具有臨界電壓補償的輸出緩衝器；在數位對類比轉換器的方面，因為液晶之穿透率和偏壓電位成一非線性關係，所以本論文也設計了一個具有珈瑪修正功能的數位對類比轉換器來補償這效應；在電位轉換器的部分，本論文則是以基底加偏壓的方式，並利用台積電0.35-μm CMOS的高壓製程，模擬且分析在不同偏壓下其操作速度和功率消耗的關係。而以上的電路皆以統寶的6-μm或3-μm低溫複晶矽製程實現。 最後，為了滿足高解析度的液晶顯示器，源級驅動電路在資料的接收端上，常會使用RSDS的規格來做傳輸介面，以增加其資料的傳輸速度並克服電磁干擾的效應，所以本論文也嘗試利用統寶的6-μm低溫複晶矽製程，設計一RSDS接收端的基本驅動電路。

In this thesis, on-glass driving circuits for LCD are designed and implemented in low temperature poly silicon (LTPS) technology. The driving circuits for LCD are divided into two parts, gate driver and source driver. Gate driver includes shift registers, level shifters, and output buffers. Source driver is composed of shift registers, latches, level shifters, a digital to analog converter, and output buffers. The implement of the on-glass source driver is the focus in this thesis. First, two circuits, which are slew rate enhancement output buffer and low power class-B output buffer, are designed to drive the heavy loading of LCD. Second, a threshold voltage compensation circuit is proposed to solve the drift of the threshold voltage in LTPS process. Third, due to the nonlinear relationship between transparency and voltage across liquid crystal, a digital to analog converter with gamma correction is adopted to compensate this effect. Finally, level shifters using body-bias technique are also proposed. According to TSMC 0.35-μm CMOS HV process, the operational speed and power consumption of level shifters in different body-bias voltages are simulated and analyzed. All of above circuits have been implemented in TOPPOLY 6-μm or 3-□m LTPS process. Moreover, in order to satisfy the high resolution LCD, source driver usually employs the specification for reduced swing differential signaling (RSDS) as the transition interface in the data receiver. Besides, the application of the specification for RSDS will increase the data transition speed and reduce the electric magnetic interference (EMI) effect. So, a fundamental RSDS receiver in TOPPOLY 6-μm LTPS process is also included in this thesis.