【作者】 陈春鹏；

【导师】 朱樟明；

【作者基本信息】 西安电子科技大学 ， 微电子学与固体电子学， 2009， 硕士

【摘要】 电源是电子设备的重要组成部分,其性能的优劣直接影响着电子设备的稳定性和可靠性。随着电子技术的发展,电子设备的种类越来越多,其对电源的要求也更加灵活多样。Buck DC/DC变换器由于电路结构简单、调整方便、可靠性高等优点,在降压式场合一直得到广泛的应用。本文设计的是一款电流型PWM控制方式Buck DC/DC变换器芯片。该芯片工作频率固定为380kHz,内部集成功率开关管,输入电压范围4.75V～23V,输出电压在0.92V～23V连续可调,并具有欠压、过流、过热等保护功能,配以简单的外围电路就可以构成完整、可靠的Buck DC/DC变换器。文中分析和阐述了Buck DC/DC的电路拓扑结构及控制电路的工作原理。对该变换器芯片各功能模块,如基准电压电路、过热保护电路、误差放大电路、电压比较电路、锯齿波振荡发生电路、自举驱动电路、欠压保护电路、电流检测电路等进行了设计并给出了仿真验证结果。最后通过对变换器芯片应用电路的Hspice仿真,验证了设计方案和理论分析的可行性和正确性,所设计的Buck DC/DC变换器达到了预期的要求。更多还原

【Abstract】 Power supply is one of the important parts of electronic equipments. Its performances affect directly the stability and reliability of electronic equipment. With the development of electronic technology, the types of electronic equipment are becoming more and more, so the requirements for power supply are more flexible and diverse. With the advantages of simple structure, convenient regulation and high reliability, Buck DC/DC converter is widely used in voltage step-down situation.A current-mode PWM control Buck DC/DC converter chip was designed in this paper. The chip with a built in internal power transistor, has a fixed 380kHz of operating frequency, input voltage range of 4.75V~23V, adjustable output voltage of 0.92V~23V, and with several protection circuits, such as the circuits of under-voltage, over-current, over-temperature. The chip can constitute a complete and reliable Buck DC/DC converter with a minimum number of external components.The thesis analyzed the operational principles of Buck DC/DC topology circuit and control circuit. It is integrated with many function modules, such as bandgap reference voltage circuit, over-temperature protection circuit, error amplifier, voltage comparator, saw-tooth oscillator, bootstrap drive circuit, under voltage lockout circuit, current sensing circuit, etc. All these circuit structures and operation principles are designed and simulated. Finally the feasibility and validity of design method and theory analysis are proved by the simulation results of application circuit of the chip with Hspice of the EDA tool. The chip can realize the prospective target.更多还原