宽输入恒压恒流降压型转换器的设计与研究

发布时间：2018-05-11 17:36

本文选题：恒流控制 + 电缆压降补偿　；参考：《西安电子科技大学》2014年硕士论文

【摘要】：随着越来越多的便携式电子设备融入我们的日常生活,人们对电子设备的性能要求也在不断的提高,这也有力的推动了我们对电源管理类芯片的研究与创新。宽输入范围、高效率、带载能力强、抗干扰能力强等已成为衡量电源管理类芯片性能优劣的主要指标。因此,研究如何在不影响其他性能的前提下提高这些指标已成为当今开关电源设计的主要研究方向。本论文对降压型DC-DC转换器的工作原理做了深入的研究,在此基础上设计了一款宽输入恒压恒流降压型DC-DC转换器。该芯片采用了峰值电流模PWM控制方式,降低了环路补偿的难度,有效的提高了系统对负载变化的瞬态响应能力。在轻载时采用BURST调制方式,提高了轻载时芯片的效率,使该芯片在全负载范围内都能保证很高的效率。论文提出了一种新颖的恒流控制方式,通过外挂电阻的阻值设置恒流模式的电流值,有效的提高了输出电流的精确性和可控性,节省了芯片面积,并且改善了传统电流采样方式损耗大的缺点。根据恒压模式下,芯片的输出电流与误差放大器的输出电压成一定的比例关系,设计了一种高效的输出电缆压降补偿电路,对输出导线上的压降所导致的输出电压的降低进行了抑制,提高了输出电压的精确性。此外,芯片还集成了逐周期的过流保护、软启动、过温、短路、过压欠压等多种保护功能以确保芯片的正常工作。论文首先介绍了开关电源的发展趋势以及选题的目的和意义,接着介绍了开关电源的拓扑结构及其工作原理,然后对开关电源的零极点对电压环路和电流环路的稳定性影响进行了探究并讨论了关于外围器件选择的一些问题。紧接着介绍了几个重要的子模块和版图设计中一些基本规则和注意事项。基于某公司0.35 um BCD工艺模型,采用Candencc Spectre仿真软件对芯片的各个子模块进行了设计和仿真,并对芯片功能进行了仿真测试,完成了芯片的整体版图设计。该转换器的输入电压范围为10V~40V,最大输出电压为12V,最大输出电流为3A。正常工作情况下,转换器的工作频率为225KHz,效率可达94%,满足设计指标要求。此款芯片适用于车载充电器/适配器、便携式充电设备、通用CC/CV充电应用等。
[Abstract]:As more and more portable electronic devices are integrated into our daily life, the performance requirements of electronic devices are also continuously improved, which has promoted our research and innovation on power management chips. Wide input range, high efficiency, strong load capacity, strong anti-jamming ability have become the main indicators to evaluate the performance of power management chips. Therefore, how to improve these indexes without affecting other performance has become the main research direction of switching power supply design. In this paper, the working principle of the reduced voltage DC-DC converter is deeply studied, and a wide input constant voltage and constant voltage step-down DC-DC converter is designed. The chip adopts peak current mode PWM control mode, which reduces the difficulty of loop compensation and effectively improves the transient response ability of the system to load change. The efficiency of the chip is improved by adopting BURST modulation mode in the light load, and the efficiency of the chip can be guaranteed in the whole load range. In this paper, a novel constant current control method is proposed, which can effectively improve the accuracy and controllability of the output current and save the chip area by setting the current value of the constant current mode by the resistance value of the external resistance. It also improves the shortcoming of the traditional current sampling method. According to the proportional relationship between the output current of the chip and the output voltage of the error amplifier in constant voltage mode, an efficient output cable voltage drop compensation circuit is designed. The reduction of the output voltage caused by the voltage drop on the output wire is restrained and the accuracy of the output voltage is improved. In addition, the chip also integrates a variety of protection functions such as periodic over-current protection, soft-start, over-temperature, short-circuit, over-voltage and under-voltage to ensure the normal operation of the chip. This paper first introduces the development trend of switching power supply and the purpose and significance of the topic, then introduces the topology of switching power supply and its working principle. Then the influence of zero pole of switching power supply on the stability of voltage loop and current loop is discussed and some problems about the selection of peripheral devices are discussed. Then several important sub-modules and some basic rules and considerations in layout design are introduced. Based on the 0.35um BCD process model of a certain company, each sub-module of the chip is designed and simulated by using the Candencc Spectre simulation software, and the function of the chip is simulated and tested, and the overall layout design of the chip is completed. The input voltage ranges from 10 V to 40 V, the maximum output voltage is 12 V, and the maximum output current is 3 A. Under normal working condition, the frequency of the converter is 225 kHz, and the efficiency can reach 94kHz, which meets the design requirements. This chip is suitable for car-mounted charger / adapter, portable charging equipment, universal CC/CV charging application, etc.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM46

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