具有快速瞬态响应的电压模式Buck变换器设计

发布时间：2018-01-30 21:32

本文关键词： 参考电压选择电路阈值电压控制电路过冲电压瞬态恢复时间软启动电路　出处：《合肥工业大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着手机、笔记本电脑、数码相机等便携式电子产品的更新换代与发展,对它们的“心脏”电源管理芯片的要求也越来越高。传统的线性稳压器由于压差大时所表现出的功耗问题已无法满足高效系统的需求。开关变换器由于效率高,并且输出电压可升降的优点,正逐步应用于低功率领域并取代线性稳压器的市场地位。为了改善负载快速变换对电源系统所带来的影响,本文设计了一款具有快速瞬态响应的电压模式Buck变换器。针对电压控制Buck变换器提出了一种参考电压可选择的设计方案,通过参考电压选择电路和阈值电压控制电路来选择不同的参考电压,实现了Buck变换器的快速瞬态响应。设计采用0.18μm CMOS工艺,仿真结果表明,该变换器能在负载瞬态变化的情况下实现输出过冲电压小于100mV,并且瞬态恢复时间小于13μs,与传统的电压控制模式相比,具有更好的瞬态响应性能。为了消除电源上电启动阶段时由于误差放大器工作于非平衡状态所带来的浪涌电流与过冲电压,本文还设计一种新颖的软启动电路。软启动电路采用了斜坡发生器产生的间歇式脉冲VPL作为电容充电的控制信号。一方面,VPL在低电平时为软启动电容充电,在高电平时则保持软启动电压值不变,使软启动电压线性阶梯上升。另一方面,该软启动电路还通过两个电流源I1及I2相减,获得一个较小的软启动充电电流I1-I2。通过两者的共同作用,有效延长了软启动的时间。仿真结果表明,该软启动电路的启动时间为324μs。
[Abstract]:With the mobile phone, notebook computer, generation and development of digital cameras and other portable electronic product updates on their "heart" power management chip requirements are also increasing. The traditional linear regulator due to the pressure difference to show when the power system has been unable to meet the high demand. Because of the high efficiency switching converter. The advantages and the output voltage is adjustable, which is gradually applied in low power field and replace the linear regulator's market position. In order to improve the load effect brought by the rapid transformation of the power supply system, this paper designed a voltage mode Buck converter with fast transient response. The voltage controlled Buck converter is put forward a design scheme the reference voltage can be selected, through the choice of reference voltage circuit and threshold voltage control circuit to choose different reference voltages, realizes fast transient Buck converter State response design using 0.18 m CMOS technology, the simulation results show that the converter can achieve the output voltage overshoot is less than 100mV in the transient load changes, and transient recovery time is less than 13 s, compared with the traditional voltage mode control, the transient response has better performance. In order to eliminate the power on start stage due to surge current error amplifier in non-equilibrium state and caused by the voltage overshoot, this paper designs a novel soft start circuit. The control signal soft start circuit adopts an intermittent pulse VPL ramp generator produced as capacitor charging. On the one hand, VPL usually charging soft start capacitor in low electricity, in the high level while maintaining the soft start voltage is constant, the soft start voltage linear stepped up. On the other hand, the soft start circuit through the two current source I1 and I2 subtraction, to obtain a smaller The soft start charging current I1-I2. effectively prolongs the time of soft start through the combination of both. The simulation results show that the start-up time of the soft start circuit is 324 s..

【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM46

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