應用於主動矩陣有機發光二極體電源供應之單電感雙極性輸出轉換器

Abstract

在傳統AMOLED的電源管理積體電路中，它由兩個升壓轉換器和一個反向降壓-升壓轉換器組成。近年來，大多數研究集中於利用傳統的單電感雙輸出轉換器架構，試圖將三組大電感減少為兩組，並強調控制暫態響應以減少電感和電容的值。本論文提出了可應用於AMOLED電源供應之KY單電感雙極性輸出轉換器。傳統的升壓轉換器功率開關需要承受較大的跨壓且需要大的輸出電容來抑制輸出電壓漣波。為了改善以上所述缺點，本文提出使用了全NMOS的功率開關之積體化KY轉換器，並且使用了其功率級電路上的飛電容提供驅動電路電源，透過電荷流量分析可以得知，在特定比率之轉壓比之下，能夠獲得比傳統升壓轉換器更好的效率。 此外，本論文中使用切換式電容轉換器作為提供負輸出電壓之轉換器，透過切換是電容轉換器中的飛電容之隔離，使得兩輸出電壓之交叉調整率有顯著之改善。而使用交錯架構之切換式電容轉換器改善了切換式電容轉換器輸出電流不連續的問題，使得正輸出電壓不因後端切換器之負載而影響。 另外，本文透過電導調變控制的方式控制切換式電容轉換器之輸出電壓，使其能夠操作在快速切換極限模式並保證輸出電壓為所設計之電壓值。透過偵測切換器之負輸出電壓，調整功率開關之導通電阻大小，進而控制輸出電壓。 本論文之所提出之KY單電感雙極性輸出轉換器使用T18HVG2製程技術實現，量測結果雖不盡人意，但已對晶片內部所遇到的問題得到結論。從模擬結果上來看，負載電流從30 mA到350 mA的效率皆大於85%，在負載電流為160 mA時達到峰值效率為90.9%，正輸出電壓之交叉調節率為0.184 mV/mA ，負輸出電壓之交叉調節率為0.04 mV/mA。

In traditional AMOLED power management integrated circuits, the system typically consists of two boost converters and one buck-boost converter. In recent years, most research has focused on utilizing traditional single-inductor bipolar-output (SIBO) converter architectures, aiming to reduce the number of large inductors from three sets to two sets and decrease inductor and capacitor values. This thesis proposes a KY-SIBO converter applied in AMOLED power supply. Traditional boost converter power switches endure significant voltage stress and require large output capacitors to suppress output voltage ripple. To address these issues, this thesis proposes an integrated KY converter employing all-NMOS power switches and utilizing flying capacitors in its power stage to provide power to the driving circuit. Through charge flow analysis of the KY boost converter, the efficiency when utilizing the KY boost converter is better than that of the traditional boost converter at specific conversion ratios. Additionally, this thesis employs a switching capacitor converter as the negative output voltage provider, achieving significant improvements in the cross-regulation rate through flying capacitor isolation between two output voltages compared to traditional single-inductor bipolar-output converters. The interleaved switching capacitor converter addresses the issue of discontinuous input currents in the switching capacitor converter, ensuring that the positive output voltage of the single-inductor bipolar-output converter remains unaffected by the load of the SC converter. Furthermore, this thesis proposes a controller that uses conductance modulation of the switching capacitor converter's negative output voltage to ensure the converter operates in Fast Switching Limit (FSL) mode and stabilizes the negative output voltage with a reference voltage. By detecting the negative output voltage of the proposed converter, the controller adjusts the Rds,on of power switches to ensure the desired output voltage. The KY-SIBO converter proposed in this thesis is fabricated in the T18HVG2 process. Although the measurement results are not ideal, conclusions have been drawn regarding the issues encountered within the chip. The efficiency for loading currents ranging from 30 mA to 350 mA is greater than 85%, with a peak efficiency of 90.9%. The cross-regulation in the positive output voltage is 0.184 mV/mA, while the cross-regulation in the negative output voltage is 0.04 mV/mA.