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標題: | 探討同步整流降壓型轉換器緩啟動時的預偏輸出 Soft start of a Synchronous Rectifier Buck Converter with Pre-biased Output |
作者: | Pei-Yuan Chen 陳培員 |
指導教授: | 陳德玉(Dan Chen) |
關鍵字: | 同步整流降壓型轉換器,緩啟動,預偏電壓,電壓突降,湧入電流, Synchronous rectifier Buck converter,Soft-start,Pre-bias voltage,voltage dipping,Inrush current, |
出版年 : | 2005 |
學位: | 碩士 |
摘要: | 摘要
本論文將研究同步整流降壓型轉換器(Synchronous Rectifier Buck Converter)在開機緩啟動時輸出電壓帶有預偏電壓(Pre-bias)時,輸出電壓會有突降的特性,並將舉出符合低電壓特性DDR memory (Double Data Rate Memory)電源模組的例子來探討。一般應用上,在開機時為了避免電壓、電流的超越量(overshoots)及湧入電流(Inrush Current) 與在開關閉合時所可能在電感上造成的飽和等等問題的產生,都會加入緩啟動(Soft-start)電路及預偏電壓電路。但是因為同步整流降壓型轉換器的同步整流特性使得在開機時輸出電壓會有突降的現象,此電壓突降的現象為在業界規範及應用上所不能夠允許的。所以本論文將提出解決的電壓突降電路的方法,而這個電路我們把它稱為電壓突降預防電路(DPC),此電路為電流鏡(current mirror)的架構,利用緩啟動的原理使其解決此電壓突降的現象。並經由Psipce電路模擬軟體及硬體實作的驗證之後,針對在開機時輸出電壓會有突降現象而言,證明此方法確實可行。由於本電路是採取分開(Discrete)的方式去驗證,但是對於現今講求SoC (System on Chip)的時代,相對而言電路零件體積過於巨大而分散,經過前面證明DPC電路的可行之後,未來的展望就是將DPC電路整合在一顆控制IC裡面。 Abstract A synchronous Buck dc/dc converter with current sourcing and sinking capabilities is required in low-voltage Double Data Rate Memory (DDR) applications. In many Buck converter applications, soft start of the main MOSFET switch with pre-biased output voltage condition is often necessary to avoid undesirable effects such as in-rush start current, possible inductor saturation, and output voltage overshoot. However, in a synchronous Buck converter configuration, such starting condition would lead to output voltage temporary dipping, which is disallowed in many applications. In this thesis, a control scheme to avoid such a problem is proposed and circuit-level SPICE simulations were conducted to verify the concept. And the proposed circuit concept was experimentally verified by using discrete components at the breadboard level. Although the implementation was done with discrete components, however, the scheme was conceived with the final intention of integrated circuit fabrication. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/24415 |
全文授權: | 未授權 |
顯示於系所單位: | 電機工程學系 |
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