【作者】 刘文亮；

【导师】 孙伟峰； 易杨波；

【作者基本信息】 东南大学 ， 软件工程（专业学位）， 2016， 硕士

【摘要】 反激式开关电源变换器具有体积小、电路简单、可靠性好等优点,被广泛应用于小功率电子产品中。当前随着美国DoEVI六级能效和欧盟EN55022规范等标准的推出,对变换器的效率和电磁干扰(EMI)等指标的要求越来越高。功率MOSFET驱动电路与电源变换效率及EMI直接相关,且效率和EMI间存在一定的矛盾和折中关系。本论文将重点研究和设计功率MOSFET的驱动电路,以优化电源变换器的效率及EMI。本文首先分析了反激式开关电源中功率MOSFET驱动电路的发展现状及主要设计方法,并结合功率MOSFET的开关过程和传统驱动电路所体现出来的问题,提出了-种可以提高反激式开关电源变换效率且明显改善系统EMI特性的动态驱动技术。接着研究了模拟和数字的两种动态驱动方案,两种方案均可在开关过程的不同阶段依据变换器的负载条件动态地驱动功率MOSFET,以兼顾电源的效率和EMI要求。同时依照所提出方案分别设计了对应的具体实现电路,并对电路进行了仿真分析验证。此外,论文还对动态驱动电路的版图进行了设计以及后仿真。最后对一款本设计电路所在的反激变换器样机进行了效率测试和EMI测试,并将结果分别与指标要求和传统驱动的变换器样机的测试结果进行了对比,验证了所提出电路的设计效果。仿真验证表明：变换器输出重负载和轻负载时,功率MOSFET的导通上升时间分别小于200ns和小于150ns,且关断下降时间始终小于100ns,在保证快速开关的前提下适应性地改变开关的时间。样机测试结果表明：应用动态驱动技术的基础上,5V2A样机的平均效率大于78.7%,满足六级能效的要求,且相对于传统驱动技术明显改善系统的EMI,EMI裕度在30MHz～1000MHz测试频率下均大于6dB。更多还原

【Abstract】 Flyback power converter has the advantages of small size, simple circuit and good reliability, therefore it’s widely used in lower power electronic products. With the proposal of US DoEVI energy efficiency and EU EN55022 specification and other design standards, demands on the efficiency and electromagnetic interference of power converter are getting higher and higher. Meanwhile, Power MOSFET driver circuit is directly related to the power conversion efficiency and EMI,and there is contradiction and compromisebetween efficiency and EMI. This thesis will focus on research and design of power MOSFET driver circuit, in order to optimize the efficiency and EMI of the power converter.This thesis firstly analyzed the development and main design methods of driver circuit of power MOSFET for flyback power converter. Based onthe switching process of power MOSFET and reflected problem of the conventional drive circuit, proposed a dynamic driver circuit which can significantly improve the efficiency and EMI characteristicof flyback switching power converter. Then this paper studied the analog and digital design schemes of dynamic driver circuit, both can dynamically drive power MOSFET, to adaptively fit the demands on efficiency and EMI. At the same time, this thesisdesignedcorresponding concrete realization circuit for the design.The function of the circuit was verified by simulation analysis.In addition, the paper also studied the layout design of dynamic driver circuit and post-simulation. Finally, the efficiency and EMI of a flyback power converterwith dynamic drive circuitwere tested, thenthe results were compared with energy efficiency requirements and the test results of a flyback power converterwith the conventional drive circuit, which verified the effectiveness of the proposed circuit.The simulation results show:when the converter works in heavy load and light load, the rising time of power MOSFET is less than 200ns and 150ns, and the falling time of power MOSFET is always less than 100ns, adaptively adjusting switch time on the premise of ensuring quick switch of power MOSFET.The test results showed that:dynamic drive technologycan guaranteethe average efficiency of flyback switching power converters (5V/2A)to be more than 78.7%, satisfyingthe sixth energy efficiency requirements, and greatly improve the EMI of power system compared with the conventional drive technology, EMI margin always greater than 6dB under different frequency.更多还原