一种迟滞BUCK型DC-DC转换器的设计

发布时间：2018-11-25 17:36

【摘要】：近年来,随着便携式电子产品的迅速增长,与之配套的电源管理系统也具有越来越广泛的市场。而DC-DC转换器具有许多优点诸如效率高、重量和体积都很小,因此广泛应用于各种电子系统,它是许多电路能否正常工作的关键点之一。由于起步较晚,国内的设计水平目前远远落后于国外的先进水平,基于这样的背景下,我们开始研究设计性能更为优良的DC-DC转换器。本文首先根据设计需要给出了DC-DC转换器的设计指标,结合实际状况,选择了Buck结构作为系统的拓扑结构。文章分析了几种反馈控制模式的结构特点,指出采用迟滞比较器的系统稳定性好,使用了迟滞比较器,并就环路控制上存在的问题作了详细的分析。整个转换器电路由迟滞比较器(HC)、带隙基准电压源(BGR)、线性稳压器(LDO)、过流保护电路(OC)以及过温保护电路(OTP)等电路组成。为了能够高精度、快速的实现环路控制,本文设计了具有高精度、低电流损耗的高低侧控制电路。使用Hspice软件对系统及其各个模块进行仿真,仿真结果表明:在最低输入电压为5V时,转换器的输出电压范围可以在0.5V-2.5V之间调节,最大负载电流可以达到1.5A。输出纹波电压小于42 mV,在100mA电流阶跃下负载调整率为0.5%,线性调整率为25 mV/V,符合初始设计指标,具有高效率,快速输出负载瞬态响应等优点。最后总结了在电路设计中遇到和克服的难点,提出了对未来工作的展望。
[Abstract]:In recent years, with the rapid growth of portable electronic products, the associated power management system has a more and more extensive market. DC-DC converter has many advantages, such as high efficiency, small weight and volume, so it is widely used in various electronic systems, it is one of the key points for many circuits to work properly. Due to the late start, the domestic design level is far behind the advanced level of foreign countries. Based on this background, we began to study the design of DC-DC converter with better performance. In this paper, the design index of DC-DC converter is given according to the design requirements. Combined with the actual situation, the Buck structure is selected as the topology of the system. This paper analyzes the structural characteristics of several feedback control modes, points out that the hysteresis comparator has good system stability and uses hysteresis comparator, and makes a detailed analysis on the problems existing in loop control. The whole converter consists of hysteresis comparator (HC), bandgap reference source (BGR), linear voltage regulator (LDO), over-current protection circuit (OC) and over-temperature protection circuit (OTP). In order to realize the loop control with high precision and high speed, the high and low side control circuit with high precision and low current loss is designed in this paper. Hspice software is used to simulate the system and its modules. The simulation results show that when the minimum input voltage is 5 V, the output voltage range of the converter can be adjusted between 0.5V-2.5V and the maximum load current can reach 1.5 A. When the output ripple voltage is less than 42 mV, the load adjustment rate is 0.5 under the step of 100mA current, and the linear adjustment rate of 25 mV/V, accords with the initial design index. It has the advantages of high efficiency, fast output load transient response and so on. Finally, the difficulties encountered and overcome in circuit design are summarized, and the prospect of future work is put forward.
【学位授予单位】：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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