用於可選擇式多輸出直流-直流轉換器之改良雙相位交錯式電荷幫浦技術

Abstract

液晶顯示面版越來越普及，應用的範圍越來越廣。從掌上型電玩，手機等小型液晶顯示面版到液晶電視甚至戶外液晶顯示看板之大型液晶顯示面版。因此液晶面版的電源供應也越來越重要。電源供應區塊也希望能夠整合至驅動電路之內，因此朝著縮小晶片面積以及外部元件的縮小方向前進。 液晶顯示器的電源需要多組不同位准的電壓來對液晶進行充放電的動作。而在直流電壓轉換器當中，電感式直流電壓轉換器需要外部元件電感，而電荷幫浦需要外部元件電容。比較之下，電感較電容佔較大面積，而在應用上，液晶顯示面版需要一個負的電壓位准來對液晶電容做放電動作，電感式直流電壓轉換器無法產生負的電壓位准。因此在成本與面積的考量之下，我們利用電荷幫浦取代了常見的電感式直流電壓轉換器。而電荷幫浦在操作時會產生的漣波利用改良式的雙相位交錯式電荷幫浦架構來減少漣波。 本論文實現了一個使用改良的雙相位控制電荷幫浦對輸出做可切換式選擇的多輸出直流-直流電源轉換器。輸入為10V的高電壓，可以提供四組不同的電壓選擇，分別為10V、20V、-10V以及0V，最大電流負載為50mA。利用TSMC 0.25um BCD 2.5V/5V/12V/40V 1P5M 製程進行模擬以及製作驗證。

LCD panels are going more and more popular. The applications of the LCD panels are widely spread in our daily life. From the small LCD panels on palmtop entertainment machine and cell phone to the large LCD panels on LCD TV or outdoor display screen. Therefore, the power supply blocks for LCD panels are more and more important. The needs to integrate the power supply block into the LCD driver circuits are rise in great demands. In other words, it is necessary to reduce the size of the power supply block chip and reduce the number of the external components. The power sources for LCD panels need different voltage scale to charge and discharge the liquid crystal capacitors. Among the DC-DC power converters, inductive switching converters need external components as inductors and charge pumps need external components as capacitors. Compare these two external components inductors and capacitors, inductors occupy larger board area than that of capacitors. Besides, LCDs need a negative voltage to discharge the liquid crystal capacitors. It is difficult for Inductive switching converters to generate a negative voltage. Therefore, for cost and area considerations, we use charge pumps to replace inductive switching converters. In this thesis, the ripple of the charge pump is further reduced by an improved double phase cross-coupled charge pump structure. This thesis implements a switchable multi output DC-DC converter utilize improved dual phase cross-coupled charge pumps. The input voltage is a high voltage 10V. The circuit can supply 4 different output voltages, 10V, 20V, -10V and 0V. The maximum current load is 50mA. The chip is simulated and fabricated by TSMC 0.25um 2.5V/5V/12V/40V 1P5M BCD process CMOS technology.