可外同步大电流Buck变换器控制环路的研究和设计

发布时间：2018-04-12 16:38

本文选题：电流模控制 + 斜坡补偿　；参考：《电子科技大学》2016年硕士论文

【摘要】：功能日益强大的电子系统大多采用负载点电源供电,对该类电源的要求是高可靠性、高效率和高功率密度,甚至一些电池供电的设备要求负载点电源能够在很低输入电压的情况下正常工作。这些高要求无疑给电压转换器的设计带来新的挑战。电流模的开关电源芯片因其补偿环路简单、动态性能好等优点,被广泛用来做负载点电源。然而,电流模式控制容易受一些因素的影响,比如不合适的斜坡补偿会导致次谐波振荡或者环路响应变差等。本文旨在设计一款高性能降压型电流模单片开关电源芯片,输入电压4V-7V,输出电压0.8V-6.3V,最大负载电流6A。其主要特点是开关频率可以根据实际应用进行调节或者外同步,而频率的改变会对斜坡补偿和环路稳定性等控制环路方面产生影响,本文重点围绕这个问题展开分析和研究。在对传统的线性分段斜坡补偿和二次斜坡补偿电路分析的基础上,提出一种新颖的自适应二次斜坡补偿电路,其补偿斜率不仅可以随着输入输出电压而变化还能根据开关频率和电感值的大小而自适应的改变,使得电流控制环在不同的应用条件下都有很好的瞬态响应;另外,为了满足在全负载范围的条件下,开关变换器都有高的效率,采用了一种最小占空比电路以使变换器在由重载到轻载转变时,调制模式自动从PWM切换到PSM模式,实现双模式调节;最后,对补偿部分的跨导放大器进行了改进设计,使得整体系统的瞬态响应得到很大的改善。最后,本论文中的设计是基于0.35μm的BCD工艺进行的,所有的仿真结果都已满足指标。目前整体版图已经拼好,且通过DRC规则和LVS验证。
[Abstract]:The electronic system becomes more and more powerful function mostly uses the point of load power supply, the power supply requirements are high reliability, high efficiency and high power density, and even some battery powered equipment requirements point of load power supply can work normally in a very low input voltage conditions. These high requirements to voltage converter design will undoubtedly bring new challenges the current mode switching power supply chip. Because of its advantages of simple loop compensation, good dynamic performance, is widely used for point of load power. However, current mode control is easily affected by some factors, such as inappropriate slope compensation will cause harmonic oscillation or loop response variation. The purpose of this paper is to design a monolithic current mode high performance buck type switching power supply chip, the input voltage 4V-7V, output voltage 0.8V-6.3V, maximum load current of 6A. and its main feature is the switching frequency can be according to the actual stress With the adjusted or external synchronization, and frequency change will affect the stability of slope compensation and loop control loop, this paper focus on the analysis and Research on this issue. In the traditional linear piecewise slope compensation and analysis of the two slope compensation circuit based on a novel adaptive slope two the compensation circuit, the compensation slope can not only with the input voltage and the output voltage can vary according to the size and the change of adaptive switching frequency and inductance value, the current control loop in different application conditions have good transient response; in addition, in order to meet the full range of load conditions, switching converter has high the efficiency of using a minimum duty ratio circuit to make the converter by heavy load to light load change, automatic modulation mode switching from PWM to PSM mode, realize the dual mode adjustment; the After the compensation part of the transconductance amplifier was designed to improve the transient response of the whole system, which greatly improved. Finally, the design in this paper is the BCD technology based on M 0.35, all the simulation results meet the target. At present, the overall layout has good fight, and through the DRC and LVS rules verify.

【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM46

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