【作者】 孙毛毛；

【导师】 冯全源；

【作者基本信息】 西南交通大学 ， 微电子学与固体电子学， 2007， 硕士

【摘要】 随着电子设备的飞跃发展，电子系统的心脏——电源也得到了迅速的发展，并对其要求越来越高。开关电源被誉为高效节能电源，它具有稳压范围宽、功率密度比大、重量轻等优点，同时它在开关管上较少的能量损耗使它与线性电源相比，具有较高的效率，最高效率可达90％以上，从而使它在移动便携式设备中得到了广泛的应用，因此开展开关电源项目研究具有重要意义。本论文的研究和设计获得了国家自然科学基金和四川省重点项目的联合资助。本文介绍了Buck开关电源的基本原理，对它的各种控制技术进行了详细的描述；通过比较各种控制方式的优缺点，指出了它们各自的应用场合。本文设计了一款应用于便携式移动设备中的降压型开关电源的关键控制电路：PWM求和比较器和同步整流器电流控制比较器，并对它们的工作原理、电路结构和小信号特性进行了重点的分析和描述。同时针对PWM电流模式的缺点，根据斜坡补偿原理，利用时钟信号设计了一个斜坡产生电路。PWM控制电路是开关电源的核心控制部分，它实现了控制算法，其性能直接影响了系统的性能；低功耗的同步整流器目前已广泛应用于小功率直流开关电源中，通过对它的控制可以解决PWM控制方式轻载情况下转换效率低的问题。本文设计的PWM控制电路采用了一种新的形式取代误差放大器，即求和比较器的形式，它的增益可高达120分贝；设计的同步整流器电流控制比较器可以根据负载情况调整阈值电压，同时它具有较高的增益：约96分贝。本文设计的电路采用BiCMOS 0.6um工艺，利用HSPICE软件对设计的电路进行了仿真，仿真结果符合设计需要。同时，通过对开关电源系统的仿真对设计电路的功能进行了验证。更多还原

【Abstract】 As the heart of the electronic system, the power supply develops fast with the fast development of the electric devices, and the requirement is more and more high. The switch mode power supply (SMSP) is called as the high efficiency power supply. It has many virtues such as wide stable output ranges, large power density ratio, lightness and good performance. Its fewer losses on the switch bring it high efficiency compared with the linear regulator. The highest efficiency of the switch mode power supply could be above 90% and it is widely used in the portable applications. Therefore, it is of great importance to research into the switch mode power supply. The paper is supported by Nation Science Foundation of China and Sichuan Province Academic Foundation.The basic principle and control techniques of DC-DC buck converters are described in detail. The advantages and disadvantages of the control methods are analyzed and compared, and where each method is more adapted to is pointed out.The key control circuits based on DC-DC buck converter in current control mode which is used in mobile applications and portable applications are designed: the PWM sum-comparator and the current control comparator of synchronous reifications. The operational principle, structure and small signal character are particularly analyzed. To solve the problems in PWM Current mode method, a slope circuit based on the principle of slope compensation is designed.The PWM control circuit is the core of converters which realized the control algorithm. Its performance is very important in converters. The low power losses synchronous reification (SR) is widely applied in low power DC converters. The SR control method can effectively solve the problem that the efficiency is too low in light loads.A new type of PWM comparators is designed: the sum-comparator. It replaces the error amplifier and improves the performance: the gain is approximately 120DB. And the current control comparator of synchronous reifications can adjust the threshold to the load. Its gain is approximately 96DB. The circuits are designed in BiCMOS 0.6um process. Simulate the circuits with HSPICE and the results indicate that the design have achieved the expected characteristics. The system simulations verify the function of the designed circuits.更多还原