【作者】 景欣；

【导师】 李新；

【作者基本信息】 沈阳工业大学 ， 微电子学与固体电子学， 2009， 硕士

【摘要】 开关稳压电源具有集成度高、外围电路简单、电源效率高等优点,在各种电子产品中得到广泛的应用。尤其是基于电池供电的便携式系统数量日益增长,开关稳压电源已经取代效率较低的线性稳压器,成为现代超大规模集成系统中不可或缺的部分。论文阐述了电源管理芯片的市场前景与发展,研究了降压型DC-DC变换器的实现技术。在深入分析降压型开关电源工作机理的基础上,采用BUCK型拓扑结构,设计了一种PWM电流控制模式降压型DC-DC变换器控制芯片电路,该电路在4.75V～30V的输入电压范围内可实现达0.8～16V的降压功能,工作温度范围为0℃～150℃,转换效率达到90%。对基准电压源、振荡器、误差放大器、限流比较器、采样电路、锁存器、驱动电路、短路保护和过温保护等9个子电路进行了电路设计与原理分析,并在此基础上,运用EDA软件对各功能模块的各项指标、参数进行了仿真、分析。最后,进行了整体电路的功能和典型性能参数的联合仿真,仿真结果表明,设计电路达到了预定的设计目标。该芯片具有短路保护,在输出电压低于3.75V时,自动调整振荡频率;具有软启动功能,可以避免启动时的电感电流过冲;具有斜坡补偿功能,保证了芯片在电流控制模式下反馈环路工作的稳定;具有过温保护功能可以防止高温造成电路永久的损坏。芯片采用2um、36V双极工艺和SOP-8E封装形式。对设计的芯片进行了点测以及成品应用测试,测试结果表明,标准负载电流下转换效率接近90%;输入电压在7～30V下负载电流变化了0.6A;温度在20～140℃负载变化了0.3V;具有良好的电压调整率和负载调整率。设计电路基本达到设计要求。更多还原

【Abstract】 Switching regulators have been widely applied in the electronic product field,due to their high integration level,simple peripheral circuits,highly power efficiency.Especially, with the development of the battery-operated portable systems,the switching regulators are becoming an essential building block in the contemporary VLSI systems,replacing the linear voltage regulator with low power efficiency.In the thesis,the market and the development of power manager chip are described, and the technique for buck DC-DC converters is analyzed.After the basic operation principle of buck switching power supply is in detail investigated,the chip circuits of PWM current mode buck DC-DC converters are designed based on buck topology structure.This regulator can generate output voltage as low as 0.8V to 16V with wide input voltage range of 4.75V to 30V.Operating temperature range is 0℃～150℃,and conversion efficiency reaches 90%.Nine sub-block circuits including voltage references,oscillators, error amplifiers,current limiting comparators,sampling circuits,latch,driving circuits, short-circuit protection and over-temperature protection are analyzed and designed.Then several electrical characteristics are simulated and analyzed by using cadence EDA tools. Finally,the whole chip performances are simulated.And the simulation results show the designed circuits can realize the designed targets.The chip has a short-circuit protection function.When the output voltage is lower than 3.75V,the oscillation frequency can be automatically adjusted.The soft-start function can avoid the inductor current overshoot when the chip starts.The slope compensation ensures that the feedback loops in the chip circuit can stability work in the current control mode.The over-temperature protection function can prevent permanent damage because of high temperatures.2um 36V bipolar process and SOP-8E encapsulation are applied.The point measurement and the tests for product application are carried out.The test results show the conversion efficiency approaches 90%under standard load current.When the input voltage is changed from 7V to 30V,the load current will changes 0.6A.When the temperature changes from 20℃to140℃,the load current will change 0.3V.The chip has good voltage adjusting ratio and load adjusting ratio.The designed chip performances basically meet the design requirements.更多还原