使用切換式帶差參考電路主動控制之雙相位電荷幫浦之實現

Abstract

隨著可攜式電子產品的普及，電源供應區塊的重要性日益提高。無論是單一晶片或者是整合在其他晶片內的電源供應電路，電路尺寸都是相當重要的設計考量。對可攜式電子產品而言，縮小晶片面積以及減少電路板面積即代表更低的成本和更輕更小的尺寸。 在直流電壓轉換器中，電荷幫浦對外部元件的需求低於電感式直流電壓轉換器。電荷幫浦運用兩個電容即可達到升壓或降壓的目的，無需電感元件。電感的尺寸相對地較大，高度也難以縮小，常會限制到電路板的空間設計。通常，一個定電壓輸出的電荷幫浦需要帶差參考電路來提供參考電壓。在尺寸的考慮之下，我們整合了帶差參考電路與控制電路，直接利用切換式帶差參考電路來主動控制輸出電壓。此外，電荷幫浦在升壓過程會造成輸出電流的不連續現象，因此我們為這種控制方式設計了一個全新的雙相輸出電荷幫浦來降低輸出漣波。 本論文實現了一個利用切換式帶差參考電路來控制輸出電壓的雙相輸出電荷幫浦。其最大負載電流為50mA，輸入電壓範圍為2.9V~5.3V，輸出電壓為5V，並使用TSMC 0.35um 3.3V/5V 2P4M CMOS製程進行設計與製作。

The demand for the portable electronic devices makes the power supply circuit more and more important. Besides, the size of the power supply circuit is the major design consideration, no matter what the circuit is fabricated as a single chip or integrated into a System-on-Chip (SoC) chip. For the portable electronic devices, the reduction of the area on silicon and print circuit broad means lower fabrication cost and tinier size. In other words, a compact power supplying system is necessary for the power management of the SoC systems. In DC/DC power converters, the charge pump needs less external components than the inductive switching converter. The charge pump can also boost or buck voltage by just two capacitors without the need of an inductor. The size of the inductor is larger and its height is hard to be shrunk. It means that the size and height of the external components will limit the layout on the print circuit broad. Thus, the power supplying system implemented by charge pump circuits is a good solution compared to the inductor-based switching circuits. Usually, the regulated charge pump circuit needs a bandgap reference circuit to provide a temperature-independent reference voltage. Under the consideration for the silicon area, we integrate the bandgap reference circuit into the regulation circuit. We use the switched-capacitor based bandgap reference circuit to regulate the output voltage. Furthermore, we propose a novel dual phase power stage to reduce the output ripple for this unique control scheme. This thesis implements a dual phase charge pump regulated by a switched-capacitor based bandgap reference. This charge pump provides 50mA maximum load current. The input voltage range is from 2.9V to 5.3V and the output voltage is 5V. This chip is simulated and fabricated by TSMC 0.35um 3.3V/5V 2P4M CMOS technology.