【作者】 李芳；

【导师】 郭树旭； 常玉春；

【作者基本信息】 吉林大学 ， 电路与系统， 2006， 硕士

【摘要】 近年来便携式设备的使用越来越广泛,同时对电源的要求也是越来越高。开关电源以其重量轻、体积小、效率高、稳压范围宽等优点,在计算机、手机及PDA等许多电子设备中得到了广泛的使用。本论文的主要工作是:根据开关电源在不同控制方式下的工作特点,对比了电流控制和电压控制两种模式,分析了各自的优缺点,提出一种升压式电流控制PFM(脉冲频率调制)的DC-DC转换器的设计。首先对芯片的工作原理和系统构成进行了研究和分析,包括开关电源变换器的整个主回路以及控制回路。在系统设计完成后,根据设计要求再确定单元模块。利用Hspice电路仿真软件对单元模块电路进行验证仿真,在单元模块达到设计要求后再进行联合方真。系统的仿真结果表明在控制信号无效的状态下,芯片消耗的静态电流仅为10nA,极低的关断电流有利于节省电能,延长便携式设备电池的使用时间。更多还原

【Abstract】 The switching power supply with small volume and weight as well as high efficiency and low power waste have been widely used in domain of electronic computer、communicate facility、electronic apparatus、domestic electric appliances. the present paper based on the use battery power supply portable electronic products application background, has studied the boost stage switching power supply chip with pulse frequency modulation mode control. The traditional PWM switch voltage-stabilized supply uses the voltage control pattern, takes the feedback signal realizes closed-loop control of the output voltage sampling to stable output voltage only. circuit inductance has not participated in the control, it is the independent variable. the switch converter is the second order system with two state variable, namely output filter capacity voltage and output filter inductance current. The second-order system is one has the condition stable system, only then carries on the careful design and the computation to the control circuit, satisfies the controlled condition, the closed-loop system can be stable. Therefore, this article uses the current control mode and adds the current feedback loop for inductance current no longer is an independent variable, the switch converter to become a first-order unconditional stable system.This chip integrates NMOS power tube, has the low resistance. the bigger of the switch, the smaller the on-state resistance is. Considering the area that the actual chip takes up, it is impossible to enlarge the aspect ratio of the switch infinitely. Therefore according to the situation that the chip takes the circumstance of the load normally, it was carried on compromised. And the increasing of the size of switch must cause the big parasitic capacitance. This will effect the speed of MOSFET switch, so the paper designs the drivers for both switches respectively. Using the PMOS isolator to be possible to separate the power source and the inductance connection, the current will decrease to更多还原