單電感正負電壓輸出轉換器之穩態分析

Abstract

手持式電子裝置中，需要同時供應多組不同電壓使其內部電路正常運作，因此需使用多組直流轉換器將電池轉成多組需求電壓。因每組轉換器皆需一個電感，數組電感在裝置中顯的體積龐大且笨重。近年來提出僅用一個電感即可提供多組電壓輸出之電路，本論文研究之電源轉換器即出自此新型架構，可輸出一正壓及一負壓，稱此為單一電感雙極性輸出電源轉換器（Single-inductor-dual-output Bipolar Converter 簡稱 SIDO-Bipolar Converter） 本論文將針對SIDO-Bipolar Converter之穩態做分析，推導其在連續導通模式(CCM)下及非連續導通模式(DCM)下之穩態方程式。穩態方程式由電路數個已知相關參數組成，可用來求得電壓增益、兩開關之導通時間週期等電路特性值。與單輸出電源轉換器比較，雙輸出之穩態方程式相當複雜。在已給定電路規格下(含輸入電壓、輸出電壓及負載、操作頻率、電感值)，本論文設計出一流程步驟圖，可得出在達成此規格時兩組開關導通時間週期。研究中亦發現電壓回授控制方法中使用不同組鋸齒波將造成SIDO-Bipolar Converter之穩態方程式有所不同，論文中將有完整的歸納整理。 最後使用模擬軟體及實作電路證實理論之正確性。本論文研究之成果對於設計SIDO-Bipolar電源轉換器有相當的幫助。

Multiple voltages are often required for powering many hand-held electronic devices. In such applications, multiple DC-DC converters are often used to convert from a battery to proper multiple output voltages. Each converter usually requires one inductor for the power conversion. Therefore, multiple inductors are used for such application that is relatively bulky and heavy. In recent years, however, a new class of converters has been reported which is capable of providing multiple outputs using only single inductor. In this thesis, a converter from this family , the single-inductor dual output ( SIDO) will be investigated. This converter is capable of providing two outputs, one positive and the other negative voltages. It's therefore called SIDO bipolar converter in this thesis. An comprehensive DC analysis is performed in this thesis. From the analysis, DC equations are developed for relating various converter parameters such as voltage gains, transistor duty cycles , switching frequency, inductance, and load currents. Both the continuous mode and the discontinuous mode of converter operation are considered. These equations are much more complicated than its single-output counterpart. Algorithms are also developed for finding out the necessary duty cycles for the two transistor switches for a given converter input-output specification. It turns out that the feedback pulse-width modulation scheme also affects the DC characteristics. Simulaton and experimental results are also given to verify the theoretical equations. The results obtained in this thesis are useful for designing the SIDO bopolar converters.