應用於白光LED之升壓電路設計

Step-Up DC-DC Converter for White LED

蔡泰宏(Tai-Hung Tsai)

指導教授 ： 鍾文耀

中原大學/工學院/電子工程研究所/碩士(2008年)

https://doi.org/10.6840/cycu200900363

摘要

白光LED有體積小與省電的優點，是可攜式電子產品十分需要的，因為在有限的電池電量下，省電的LED能夠使產品有更長的運作時間。但LED的導通電壓約在3.2V至3.7V，為了使數顆LED發光效率相等，因此以串聯的形式來控制導通電流，以可攜式電子產品的電池而言，此串聯後的LED導通電壓大於電池電壓的數倍，所以需要一個升壓電路將電池電壓轉換為高電壓提供LED使用。
本論文以電流模式脈波寬度調變之升壓式轉換器電路為研究方向。經由系統的規格選擇可實現的系統架構，並以詳細而深入的理論分析探究其真相，隨之進行直流與交流分析，確保系統的穩定度與可靠度，最後將理論付諸實行，設計並整合成完整的系統電路。
本論文以TSMC 0.35um 2P4M Mixed-Signal Polycide 3.3/5V製程實現。當輸入電壓從3.3V變動至3.6V，負載串接一顆LED時，轉換效率約為80％，平均電感電流為28mA，負載電流達到預期20mA，漣波電流（峰對峰）小於33uA，系統消耗功率小於56.6mW。

關鍵字

脈波寬度調變 ； 連續導通模式 ； 尖峰電流模式 ； 升壓電路

並列摘要

Portable electronic products need white LED which advantage is small volume size and saving power. Because battery has limited power, products can have longer lifetime by using LED. LED’s forward voltage is almost from 3.2V to 3.7V, series connection of the LEDs provides identical LED currents resulting in uniform brightness. Sum of the LED’s forward voltage is several times the battery voltage, so driving the LEDs need a boost converter.
This paper presents a current-mode pulse width modulation boost converter circuit. Using system specifications to chose realizable system architecture, and detailed analysis the theorem, DC mode and AC mode to ensure the stability and reliability. Finial design the subcircuits and building a boost converter system.
This paper is designed with TSMC 0.35 2P4M Mixed-Signal Polycide 3.3/5V Process. When load is one white LED and input voltage very from 3.3V to 3.6V, the transform efficiency is about 80%, average inductor current is 28mA, load current is flowed expected 20mA and its ripple (peak to peak) is smallerthan 33uA, and system power dissipation is less than 56.6mW.

並列關鍵字

pulse width modulation ； step-up (boost) converter ； peak current-mode control ； continuous conduction mode

參考文獻

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