實現一個寬負載高效能直流對直流降壓型轉換器

On the Implementation of an Ultra-Wide-Load High-Efficient DC-DC Buck Converter

邱展毅(Chan-I Chiu)

指導教授 ： 魏慶隆

國立中央大學/資訊電機學院/電機工程學系/碩士(2011年)

摘要

可攜式電子產品輕薄短小功能完整是產品趨勢也是主要的需求，因此低功率高效能成為可攜式電子產品的首要考量，這些利用電池為電力來源的電子電路需要一個能夠提供穩定電壓的電源轉換電路，此電源轉換電路必須是低功率消耗與高轉換效能，以增加電池的壽命與延長電池的工作時間，為了提升轉換效能，本論文提出了一個電流模式控制降壓型穩壓器。

本論文所提出的電流模式控制降壓型穩壓器，其原理主要利用偵測電感上電流變化以加速負載改變時之暫態反應時間，根據電路回授機制將輸出電壓控制在所預期的數值，而不會受到負載電流的影響，再將穩壓器加入兩個P型功率電晶體，根據不同的輸出負載電流的應用，去做切換電晶體的動作，進而提升整體的轉換效能。相較於一般的電流模式控制穩壓器，此穩壓器會有較高的轉換效能，因此適用於可攜式電子產品中。

此電流模式控制降壓型穩壓器的電路設計是以台灣積體電路製造股份有限公司0.35μm 3.3V互補式金氧半製程來實現，工作電壓的範圍為2.5V~4.5V，輸出電壓為1.8V，操作頻率為2MHz，負載電流範圍為0.03A~1.2A，最大轉換效能為96.36%，在輸出負載電流為30mA時，轉換效能仍然有90%。

關鍵字

脈衝寬度調變 ； 轉換效能 ； 負載電流 ； 電流模式控制 ； 直流對直流降壓型轉換器

並列摘要

Electronic technology changes rapidly, the salient fatures of shorter, thiner, and full functionality, are the major demands of protable electronics. Low power consumption or power efficiency enhancement is the main design consideration of these portable electronics. The sub-circuits of these portable electronics use batteries as their power sources, and need a stable supply voltage generated by power converters. These power converters must have low power consumption and high efficiency to extend the service time of portable electronics. Thus, a high efficiency current mode buck converter is presented in this thesis.

This thesis proposes a current mode buck converter that senses the inductor current variation to accelerate response time, and applies the mechanism of feedback-loop theory to control the output voltage at the desired value; In order to achive ultra-wide-load and high conversion efficiency, the converter with two P-type power transistors is proposed.

This proposed current mode buck converter is implemented with TSMC 0.35μm 3.3V CMOS process. In the proposed buck converter, the operation voltage is from 2.5V to 4.5V, the output voltage is 1.8V, the operation frequency is 2MHz, the output current is from 0.03A to 1.2A, and the highest efficiency is 96.36%, when the output load current is 30mA, the efficiency is still 90%.

並列關鍵字

Pulse Width Modulation(PWM) ； Efficiency ； Load Currents ； Current-Mode Control ； DC-DC Buck Converter

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