具有過電流保護之低電壓鋰電池充電器與直流-直流降壓轉換器設計

The Design of Low-Voltage Li-Ion Battery Charger and DC-DC Buck Converter with Over Current Protection

楊國廷(Kuo-Ting Yang)

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(2012年)

摘要

本論文第一部分為使用平均電流控制技術之低電壓鋰電池充電器，採用多模充電對鋰電池充電，其操作電壓為1.5V。充電模式分別為涓流模式、定電流模式以及定電壓模式。使用平均電流控制技術不僅防止次諧波震盪發生，還能減少電路的複雜度。當工作週期超過50%依然可以正常工作，不會產生不穩定的現象。當鋰電池發生短路時，驅動電路將啟動短路保護停止對鋰電池充電。本電路使用台灣積體電路公司零點三五微米兩層多晶矽四層金屬互補式金屬氧化物半導體製程來實現，晶片面積為 2.46 x 2.68mm2 (包含PADs)。
論文第二部分為具有過電流保護之高效率磁滯電流控制直流-直流降壓轉換器，架構分為功率電晶體、主動式電流感測、取樣保持電路、磁滯電流比較電路、補償網路、非重疊與驅動電路、與過電流保護。電源管理IC的輸出電流如果過大，將使功率電晶體溫度上昇，進而造成功率電晶體燒毀。本論文在降壓轉換器加上過電流保護，過電流保護設定在650mA，達到保護作用使電源管理IC壽命延長。模擬結果顯示為輸入電壓範圍2.5V到4.2V時，輸出電壓為1.8V；在輸入電壓2.5V且負載電流150mA有最高效率93.2%。本電路使用台灣積體電路公司零點三五微米兩層多晶矽四層金屬互補式金屬氧化物半導體製程來實現，晶片面積為 1.5 x 1.5mm2 (包含PADs)。

關鍵字

鋰電池充電器 ； 平均電流控制 ； 磁滯電流控制 ； 過電流保護

並列摘要

The first part of this thesis presents a low-voltage Li-Ion battery charger which uses multimode with 1.5V supply voltage by using average-current-controlled technique. The proposed charger is operated for trickle current mode, constant current mode, and constant voltage mode, respectively. Using average-current-controlled technique not only prevents sub-harmonic oscillation but also reduces the circuit design complexity. When duty cycle is over 50%, the system still works properly, and does not produce an unstable phenomenon. If the Li-Ion battery occurs short, the driving circuit will enable the short circuit protection to stop charging battery. The low-voltage high-efficiency Li-Ion battery charger using average-current-controlled technique is implemented with TSMC 0.35μm 2P4M CMOS process, and the chip area is 2.46 x 2.68 mm2 (with PADs).
The second part of this thesis presents a high-efficiency hysteresis-current- controlled DC-DC buck converter with over current protection. The buck converter consists of two power transistors, active-current-sensing circuit, sample and hold circuit, hysteresis-current comparator circuit, compensator network, non-overlapping and driving circuit, and over current protection circuit. Generally speaking, the output current of the power management IC exceeds the current limit value will rise the temperature of power transistor, and then causes the power transistor breakdown. In this thesis, the buck converter is limited the ouput current below 650mA by using over current protection for achieving the protective effect and extending the power management IC life cycle. The simulation results show the output voltage is 1.8V when the supply voltage range is 2.5~4.2V. The maximum efficiency is 93.2% when load current is 150mA and supply voltage is 2.5V. The high-efficiency hysteresis-current- controlled DC-DC buck converter with over current protection is implemented with TSMC 0.35μm 2P4M CMOS process, and the chip area is 1.5 x 1.5 mm2.

並列關鍵字

Li-Ion charger ； average-current-controlled ； hysteresis-current-controlled ； over current protection

參考文獻

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