低電壓返馳式轉換器與鋰電池充電器之設計

The Design of Low-Voltage Flyback Converter and Li-Ion Battery Charger

游傑安(Jay-Ann Yo)

指導教授 ： 陳建中 ； 黃育賢

國立臺北科技大學/電資學院/電腦與通訊研究所/碩士(2011年)

摘要

本論文的第一部份為低雜訊低電壓之返馳式轉換器，採用TSMC 0.35μm DPQM CMOS製程實現。此部份使用同步返馳式轉換器，比起一般降升壓轉換器，返馳式轉換器輸出為正電壓，對於後端系統設計較方便。另外，比起一般傳統的返馳式轉換器，同步返馳式轉換器將二次側的二極體改用功率電晶體，利用其導通後的低電阻特性，有效地降低順向壓降和功率損耗，適合輸出為低電壓的設計。本晶片控制迴路利用三角積分調變器電路，將誤差放大器的輸出數位化，產生一位元的量化輸出，此輸出可改變返馳式轉換器的責任週期，使轉換器可執行升降壓功能，另外，三角積分調變器電路具有超取樣及雜訊移頻之功能，可將頻帶內的雜訊濾除，對於後端是射頻、通訊或音頻之設計較有利。
本論文第二部份為低電壓鋰電池充電器，其採用TSMC 0.35μm DPQM CMOS製程實現。為了克服攜帶式產品能源的問題，利用獵能器把所獵取之能量儲存至超級電容上面，而超級電容會充至1.8V，此晶片再使用升壓型轉換器對鋰電池做充電，將鋰電池充電至4.2V。晶片輸入電壓為1.8V且使用恆流恆壓模式進行充電，此顆晶片擁有放電電流感測電路，在恆流模式時，以100mA做為充電電流，而在鋰電池充飽至4.2V時，轉為恆壓模式。

關鍵字

三角積分調變器 ； 返馳式轉換器 ； 鋰電池充電器

並列摘要

The first part which is low-voltage low-noise flyback converter using delta-sigma modulator is presented in this thesis. The synchronous flyback converter is adopted in this system. Comparing with traditional flyback converter, the second-side switch of synchronous flyback converter is more ideal because RON of power transistors is lower than diode. The delta-sigma modulator which makes error signal digitalize and produces one-bit quantity output signal to adjust duty cycle is controller in this system. Besides, this modulator which utilizes noise-shaping and oversampling characteristics to reduce in-band noise is suitable for RF, audio or communication applications. The proposed circuit is implemented with TSMC 0.35um CMOS DPQM process.
The second part offerings the low-voltage li-ion battery charger in the latter half of the thesis. For solving energy problem in portable product, utilizing energy harvesting system to catch selected energy into super capacitance which be charged to 1.8V. And then, the proposed chip charges li-ion battery from the energy source super capacitance. When li-ion battery voltage is lower than 4.2V, the charging system which charges battery by constant 100mA or constant voltage is in constant current mode. However, while battery voltage is higher than 4.2V, the charging system supplies constant 4.2V to li-ion battery in constant voltage mode.

並列關鍵字

Delta-sigma modulator ； flyback converter ； li-ion battery charger

參考文獻

[17] 楊盛惟，應用於數位音頻系統之微功率開關電容三階三角積分調變器設計，國立臺北科技大學電腦與通訊研究所，碩士論文， 2007。

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