具雙端輸入雙端輸出誤差放大器以及負載調節增強機制的降壓式電源轉換器

Abstract

在消費性電子產品中，尤以手持式產品的應用上，需求越來越廣泛。擁有高效能與小型化的電源轉換器日趨重要。為了有效使用有限的電池能量，電源管理系統為晶片系統中非常重要的一環。。 切換式電源轉換器因其高效率而被廣泛地運用於電源管理模組中。然而，切換式電源轉換器通常需要外部電感以及電容。更甚者，由於系統穩定性的因素，還需要外部補償電容以及電阻作為系統補償之用。相對線性穩壓器(Linear Regulator)來說，在系統整合上，切換式電源轉換器會佔據大部分的面積。因此，如何縮小電源模組的面積，同時又能兼顧高效能的電源轉換器，將是一個重要的課題。 本論文所提出的內容，是利用一個雙端輸入雙端輸出的誤差放大器以及P 補償的方式來移除外部補償電容的使用。然而，因為採用不同的補償方式，在負載調節(Load Regulation)的表現勢必要有所補償。因此，負載調節增強機制(Load Regulation Enhancement Mechanism)在此論文提出，用來改善負載調節表現，來實現一個不需任何補償元件，負載調節表現良好的電源管理晶片。實驗結果顯示，負載調節為0.25mA/mV。而在系統暫態響應部分，負載電流由100mA至500mA時，系統約在13μS可回復輸出電壓值。 本論文所提出的方法運用於電流模式直流/直流降壓轉換器上，並用台灣積體電路公司二五微米製程來實現。實驗結果顯示本論文的方法不需任何補償元件，也可以使系統穩定，並且也有良好的負載調節以及暫態恢復時間表現。

In recent years, portable devices involve several integrated chips with different functionality into the same printed-circuit-board (PCB) for achieving various functions. It needs a highly integrated power management module to reduce the volume and weight in order to keep up with the trend of compact size. Unfortunately, the off-chip inductor and capacitors for the high-efficiency switch-mode DC-DC converters occupy the large PCB area. That results in the extra manufacture cost and the problem for system-on-a-chip (SoC) integration. In addition, the parasitic inductive or capacitive coupling path generated from the bonding wire forms a harmful interference, which can be eliminate by integrating the off-chip components as many as possible. In other words, a highly integrated power management module is necessary for achieving high performance and small footprint area in today’s power management design. This paper proposes a differential-in differential-out (DIDO) error amplifier with the P compensator to remove the use of the compensation capacitor. However, owing to the change of the compensation method, the load regulation performance should be compensated. Thus, the load regulation enhancement mechanism (LRE) is proposed in this paper to enhancement the load regulation performance. By using the above technique, a compact size and high performance DC-DC buck converter can be guaranteed. The experimental results show that load regulation can be improved from 0.5mA/mV to 0.25mA/mV. Compared to other implementation, it does not need any compensation components to stabilize the system. The transient recovery time is about 13μS as the load current changes from 100mA to 500mA.